WO2018167801A1

WO2018167801A1 - Novel tricyclic compounds, process for preparation and use thereof

Info

Publication number: WO2018167801A1
Application number: PCT/IN2018/050137
Authority: WO
Inventors: Chepuri Venkata RAMANA; Dinesh Jagannath PAYMODE
Original assignee: Council of Scientific and Industrial Research CSIR
Current assignee: Council of Scientific and Industrial Research CSIR
Priority date: 2017-03-14
Filing date: 2018-03-14
Publication date: 2018-09-20
Anticipated expiration: 2019-09-14

Abstract

The present invention disclosed a novel tricyclic compound of formula (I), process for the preparation and use thereof in the treatment of cancer. The present invention further relates to novel compound of formula (II) which is used as intermediate for the preparation of compounds of formula (I) and process for preparation thereof.

Description

NOVEL TRICYCLIC COMPOUNDS, PROCESS FOR PREPARATION AND USE

THEREOF

FIELD OF THE INVENTION;

The present invention relates to novel compound of formula (I) and (II). More particularly, the present invention relates to novel tricyclic compound of formula (I), process for preparation and use thereof for treating or preventing cancer. The present invention further relates to novel compound of formula (I I ) which is used as intermediate for the preparation of compounds of formula (I) and process for preparation thereof.

Colchicine (1) is an alkaloid having a tricyclic ring structure. Colchicine (1), isolated as the major alkaloid in Colchicum autumnale, is one of the oldest known natural product which leads in the search for new antitumor agents. It was used as effective medicine in keen gout attacks and in familial Mediterranean fever. Colchicine is very well known for its selective binding to tubulin which disturbs the microtubule-dependent functions in the cell and thereby inhibits cellular mitosis. It binds to the cytoskeletal protein tubulin, disrupting the microtubule-dependent functions in the cell resulting in suppressing the cell division process. Along with the colchicines, another naturally occurring allocolchicines 2 is isolated and resembles to the colchicine. The in vivo stability of 2 is increased due to aromatic ring that replaced initial tropone moiety. Many unnatural allocolchicines are synthesized in search of lead candidate. Similarly, active compounds with an aryl ring C, ZD6126 (3), are functional analogue of colchicines and marketed as a drug. In literature reports, one total synthesis and one formal synthesis of 2 with a lengthy reaction sequence has been reported.

AUocolchicine has been a prominent target in natural produc synthesis, and several distinct synthetic approaches are reported. These synthetic methodologies include the transformation of natural colchicines, Diels- Alder reactions, biaryl oxidative couplings, direct arylations and Nicolas reactions, Elegant routes to several variants of allocolchicines are also reported,

Article titled "Intramolecular Nicholas Reactions in the Synthesis of Dibenzocycloheptanes. Synthesis of Allocolchicine NSC 51046 and Analogues and the Formal Synthesis of (-)- Allocolchicine" by S Djurdjevic et al. published in J. Org. Chem. , 2010, 75 (23), pp 8241- 8251 reports the preparation of dibenzocycloheptyne-Co2(CO)₆ complexes by intramolecular Nicholas reactions of biaryl-2-propargyl alcohol-Co2(CO)₆ derivatives. EP2952501 discloses a compound of formula (I), which may permit for a method or use in treating or preventing a cancer, such as pancreatic cancer or leukemia. In one embodiment, there is also pro vide a method of preparing a compound of formula (la), the method including conducting a cyclization reaction of a compound of formula (III) to obtain a compound of formula (IV), wherein conducting the cyclization reaction comprises conducting a Michael reaction in the presence of a Lewis acid.

Wherein;

R¹ and R² are independently of each other H, OH, OR', C(0)OR', OP(0)(OH)₂ or a halogen atom, or R^¾ and R together with adjacent phenyl carbon atoms form a ring structure selected from the group consisting of cycloalkyl, cycloalkenyl, heterocycloalkyl or heterocycloalkenyl having one or more of N, O and S, aryl and heteroaryl having one or more of N, O and S, wherein the ring structure is optionally substituted; R³ to R⁵ are independently of each other H or R';R^b is R", NHR", O, OH or N₃ in the formula (I) and R6 is O or OH in the formula <II);R^'' is H, OH or OR';R^s is optionally substituted aryl, optionally substituted alkyl, optionally substituted alkenyl or optionally substituted alkynyl; and R" is optionally substituted aryl, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl or optionally substituted acyl, or a salt, enantiomer or derivative thereof.

Article titled "Synthesis of indole-derived allocolchicine congeners exhibiting pronounced anti-proliferative and apoptosis-inducing properties" by Nikolay S. Sitnikov et al. in Med. Chem. Commun., 2015,6, 2158-2162 reports that based on the natural antimitotic agent allocolchicine as a lead structure, a series of novel indole-based allocolchicine congeners was synthesized and assessed in vitro for their cytostatic properties. Several compounds exhibited potent anti-proliferative and apoptosis-inducing activity towards lymphoma cells along with low unspecific cytotoxicity. The observed activity is supposed to result from the inhibition of microtubule assembly, as indicated by the tubulin polymerisation assay.

Article titled "Synthesis of aliocolchicines using sequential ring-closing enyne metathesis- diels-aider reactions" by FD Boyer et al. published in Org. Lett., 2007, 9 (4), pp 715-718 reports new allocoichinoids having functionality in the C ring at position CIO or Cl l have been synthesized using the enyne ring-closing metathesis (RCM) reaction for construction of the seven-membered ring and a Diels-Alder-aromatization sequence for the elaboration of the aromatic ring C. Article titled "Synthesis and Biological Evaluation of Thiocolchicine Analogs 5,6-Dihydro- G(S)-(acyloxy)- and 5,6-Dih ydro-6{8 )-([& royloxy)meth y 11- 1 ,2,3-tr imet hoxy-9-(m et hylt hio)-8Hcyclohepta[a]naphthalen-8-ones as Novel Cytotoxic and Antimitotic Agents" by L Sun et al. published in J. Med. Chem., 1993, 36 (5), pp 544-551 reports a series of novel thiocolchicine analogs, 5,6-dihydro-6(S)-(acyloxy)- and 5,6-dihydro-6(S)- [(aroyloxy )methy 1 ] - l,2,3-trimethoxy-9-(methylthio)-8H-cyclohepta[a]naph(halen-8-ones, possessing a six membered ring B, have been synthesized and evaluated for their cytotoxicity against various tumor cell lines, including solid tumor cell lines, and for their interaction with tubulin. The most cytotoxic compounds were 14, 15, 17, and 18, with good activity against several solid tumor cell lines.

Article titled, "Alkyne [2 + 2 + 2]-Cyclotrimerization Approach for Synthesis of 6,7- Cyclopropylallocolchicinoids" by AA More et al. published in J. Org. Chem., 2016, 81 (8), pp 3400-3406 reports a cobalt-catalyzed [2 + 2 + 2] alkyne cyclotrimerization as the final step, the short and efficient synthesis of cyclopropylallocolchicinoid and its analogues having functional group variations at C9 and/or CIO and CI 1 of ring C has been accomplished.

Diversity oriented synthesis of biologically active molecules from simple building blocks is long term goal in the field of organic synthesis. This synthetic challenge can be achieve in less number of steps by using simple but rare and novel transformations. The direc and organocatalytic approach for a-chlorination of aldehyde and cobalt catalyzed cyclotrimerization of dialkynes are well outfitted to address the above issues,

OBJECTIVE OF THE INVENTION;

The main objective of the present invention is to provide novel tricyclic compound of formula (I) and process for preparation thereof.

Another objective of the present invention is to provide novel compound of formula (II), which is used as intermediate for the preparation of compounds of formula (I) and process for preparation thereof.

Yet another objective of the present invention is to provide a pharmaceutical composition comprising a tricyclic compound of formula (I), or a stereoisomer, or ester or pharmaceutically acceptable salt thereof, and a pharmaceutical ly acceptable carrier, diluent or excipient.

Still another objective of the present invention is to provide a method for treating or preventing cancer in a subject in need thereof; comprising administering to the said subject a therapeutically effective amount of the tricyclic compound of formula (I) or a pharmaceutically acceptable salt thereof.

SUMMARY OF THE INVENTION:

Accordingly, the present invention provides novel tricyclic compound of formula (I);

Formula (I)

Wherein, Ri and R₂ may be same or different and each is independently selected from the group consisting of H, C0₂Me, CH₂CH₂CH_3, CH₂OAc, CH₂(CH₂)₂CH₃ or Ph; or a pharmaceutically acceptable salt, solvate or hydrate thereof. In an embodiment, the tricyclic compound of formula (I) is selected from Methyl (l laR)-5- acetarrddo-2-butyl-9,10,l l-trimethoxy-6,7-dihydro-5H-dibenzo[a,c][7]an-nulene-3- carboxylate (21 ), Methyl ( 1 laR)-5-acetamido-3-buty 1-9, 10,1 l-trimethoxy-6,7-dihydro-5H- dibenzo[a,c][7]-aunulene-2-carboxylate (22), Dimethyl (1 laR)-5-acetamido-9,10,l 1- trimethoxy-6,7-dihydro-5H-dibenzo[a,c][7Jajnnulene-2,3-dicarboxylate (23), (5-Acetamido- 9,10,1 l-tiimethoxy-6,7-dihydro-5H-dibenzo[a,c][7]annulene-2, 3 -diyl)bis(me-thylene) diacetate (24), N-((l laR)-9,10,l l-Trimethoxy-2,3-dipropyl-6,7-dihydro-5H- dibenzo[a,c][7]annulen-5-yl)-acetamide (25) or Methyl (l laR)-5-acetamido-9,10,l l- methoxy-3-phenyl-6,7-dihydro-5H-dibenzo[a,c][7]-annulene-2-carboxylate (26).

In an embodiment, the present invention provides a process for the preparation of tricyclic compound of formula (I) from dialkyne compound of formula (II) comprising the steps of: a) reacting dialkyne (15) with p-methoxy benzyl amine in presence of suitable base in acetonitrile for the period ranging from 70-80 hrs to afford alkyne (17);

b) protecting acetate group of the alkyne (17) compound of step (a) by stirring the reaction mixture comprising alkyne (17) of step (a) in dichloromethane (CH₂C1₂), NEt₃, dimethylaminopyridine (DMAP) and acetic anhydride (Ac₂0) for the period in the range of 3-5 h to afford N-(5-(2-Ethynyl-3,4,5-trimethoxyphenyl)pent-l-yn-3-yl)-N-(4- methoxybenzyl)acetamide (18);

c) reacting the acetamide (18) of step (b) with alkyne in presence of cyclopentadienylcobalt dicarbonyl [CpCO(CO)₂] under light for the period in the range of 10- 12 h to afford mixture of regioisomers followed by subjecting said mixture deprotection of p- methoxybenzyl group of amine by using trifluoroacetic acid/CH₂Cl₂ to afford compound of formula (I) .

In one embodiment of the present invention, the process is carried out at temperature in the range of 25 to 30°C.

In preferred embodiment, the suitable base in step (a) is caesium carbonate or calcium carbonate.

The alkyne in step (c) is selected from methyl propiolate, acetylene, Methyl 2-heptynoate, dimethyl acetylenedicarboxylate, ester of butyne diol, 4-Octyne or Methyl 3- ph en y Ipropi ol ate . In another embodiment, the present invention provides novel compound of formula (II) which are used as intermediate for the reparation of compounds of formula (I);

Wherein, R¹ is selected from CI, NHPMB or N(Ac)PMB.

In preferred embodiment, the compound of formula (II) is l-(3-Chloropent-4-yn-l-yl)-2- ethynyl-3,4,5-trimethoxybenzene (15), 5-(2-Ethynyl-3,4,5-trimethoxyphenyl)-N-(4- methoxybenzyl)pent-l-yn-3-amine (17) or N-(5-(2-Ethynyl-3,4,5-trimethoxyphenyl)pent-l- yn-3-yl)-N-(4-methoxybenzyl)acetamide (18).

In yet another embodiment, the present invention provides a process for the preparation of novel compound of formula (II) from 3, 4, 5, trimethoxybenzaldehyde comprising the steps of:

a) subjecting 3, 4, 5, trimethoxybenzaldehyde (6) for grignard reaction with 4- bromobut-l-ene to afford alcohol (7);

b) deoxygenating alcohol (7) of step (a) with suitable deoxygenating agent in presence of boron trifluoride diethyl etherate to afford aikene (8);

c) subjecting aikene compound of step (b) for oxidative cleavage to afford aldehyde

(9) followed by reduction and acetate protection of resulting alcohol to afford ester

(10) ;

d) treating ester (10) of step (c) with Iodine/silver trifluoroacetate in chloroform to afford iodo compound (11);

e) subjecting iodo compound (11) of step (d) to sonogashira cross-coupling with trimethylsilylacetylene in the presence of bis(triphenylphosphine)palladium(II) dichloride and copper iodide in dimethylformam de/diethy] amine at temperature ranging from 70 to 90 °C to afford protected compound (12) followed by one pot silyi and acetate deprotection using potassium carbonate as a base in methanol to afford alcohol (13); f) oxidizing alcohol (13) of step (e) with suitable oxidizing agent to afford aldehyde (14);

g) subjecting aldehyde (14) for asymmetric a-chlorination using suitable chlorinating and oxidizing agent in presence of L-proline and followed by treatment with Ohira- Bestmann reagent (16) with potassium carbonate in methanol to afford the desired compound of formula (II) wherein R¹ is CI;

h) reacting compound of formula (II) of step (g) with >-methoxybenzyl amine in presence of suitable base in acetonitrile for the period ranging from 70-80 hrs to afford the desired compound of formula (II) wherein R¹ is -NHPMB; and i) protecting acetate group of compound of step (h) by stirring the reaction mixture comprising compound of step (h) in dichloromethane (CH₂C1₂), NEt₃, dimethylaminopyridine (D AP) and acetic anhydride (Ac₂0) for the period in the range of 3-5 h to afford desired compound of formula (II) wherein R¹ is - N(Ac)PMB;

The suitable deoxygenating agent in step (b) is triethylsilane (Et₃SiH). The suitable oxidizing agent in step (f) is Dess-Martin periodinane. The suitable chlorinating agent in step (g) is n- chl oro s ucc inamide (NC S ) . In one embodiment, the present invention provides a pharmaceutical composition comprising a tricyclic compound of formula (I), or a stereoisomer, or ester or pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, diluent or excipient.

In another embodiment, the present invention provides a method for treating or preventing cancer in a subject in need thereof; comprising administering to the said subject a therapeutically effective amount of the tricyclic compound of formula (I) or a pharmaceutically acceptable salt thereof.

In one of the embodiment of the present invention the cancer is lung cancer, breast cancer, colorectal cancer, prostate cancer, a leukemia, a lymphoma, non-Hodgkin's lymphoma, skin cancer, a brain cancer, a cancer of the central nervous system, ovarian cancer, uterine cancer, stomach cancer, pancreatic cancer, esophageal cancer, kidney cancer, liver cancer, or a head and neck cancer. BRIEF DESCRIPTION OF THE DRAWINGS:

Fig. 1 depicts the graph which shows the cytotoxic effect of Compound 2 on A431 , LN229, HEK293T and SiHa.

Fig. 2 depicts the graph which shows the cytotoxic effect of Compound 19 on A431, LN229, HEK293T and SiHa,

Fig. 3 depicts the graph which shows the cytotoxic effect of Compound 20 on A431 , LN229, HEK293T and SiHa.

Fig. 4 depicts the graph which shows the cytotoxic effect of Compound 22 on A431, LN229, HEK293T and SiHa,

Fig. 5 depicts the graph which shows the cytotoxic effect of Compound 23 on A431 , LN229, HEK293T (with IC 50: 189.596) and SiHa ,

Fig. 6 depicts the graph which shows the cytotoxic effect of Compound 25 on A431, LN229, HEK293T and SiHa.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described in detail in connection with certain preferred and optional embodiments, so that various aspects thereof may be more fully understood and apprec ated.

The phrase "pharmaceutically acceptable salt," as used herein, is a salt formed from an acid and a base, for example an acidic or a basic salt of a molecule. An "effective amount" when used in connection with a compound of the invention is an amount of the compound of the invention, individually or in combination, that is effective for treating or preventing a condition individually or in combination with another compound of the invention. In view of the above, the present invention provides novel tricyclic compounds of formula (I) and process for the preparation thereof. The present invention further provides novel compounds of formula (II) which are used as intermediate for the preparation of compounds of formula (I) and process for preparation thereof.

In an embodiment, the present invention provides a novel tricyclic compound of formula (I);

Formula (I)

Wherein, R. and R₂ may be same or different and each is independently selected from H, C0₂Me, CH2CH2CH3, CH₂OAc, CH₂(CH₂)2CH₃, Ph.

n preferred embodiment, the tricyclic compound of formula (I) is selected from

In another embodiment, the present invention provides a process for the preparation of compounds of formula (I) from compound of formula (II) comprising the steps of:

a) reacting dialkyne (15) with p-methoxy benzyl amine in presence of suitable base in acetonitrile for the period ranging from 70-80 hrs to afford alkyne (17).

b) protecting acetate group of compound of step (a) by stirring the reaction mixture comprising alkyne (17) in dichloromethane (CH₂C1₂), NEt₃, dimethylaminopyridine (DMAP) and acetic anhydride (Ac₂0) for the period in the range of 3-5 h to afford N-(5- (2-Ethynyl-3,4,5-trimethoxyphenyl)pent-l-yn-3-yl)-N-(4-methoxybenzyl)acetamide (18);

c) reacting 18 of step (b) with alkyne in presence of cyclopentadienylcobalt dicarbonyl [CpCO(CO)₂] under light for the period in the range of 10-12 h to afford mixture of regioisomers followed by subjecting said mixture deprotection of p-methoxybenzyl group of amine by using trifluoroacetic acid/CH₂Cl₂ to afford compound of formula (I). In preferred embodiment, the suitable base in step (a) is caesium carbonate, calcium carbonate.

The aikyne in step (c) is selected from methyl propiolate, acetylene, Methyl 2-hept noate, dimethyl acetyienedicarboxylate, ester of butyne dial, 4-Octyne or Methyl 3- pheny lpropiolate .

The process for the preparation of compounds of formula (I) is carried out in presence of light (200 w) bulb.

The process for the preparation of compounds of formula (I) from l-(3-Chloropent-4-yn-l- yl)-2-ethynyl-3,4,5-trimethoxybenzene (15) proceeds by substituting chlorine with p- methoxybenzyl amine by using CS₂CO₃ as base and subsequent acetate protection afford the key intermediate diaikyne 18 followed by treatment of 18 with methyl propiolate in presence of CpCO(CO)₂ under light (200 W) for 12 h afford mixture of regioisomers which consequently subjected for p-methoxybenzyl amine deprotection by using trifluoroacetic acid/CH₂Cl₂ (2: 1 ) to afford regeoisomers 2 and 19 in 1:2 proportion.

The process for the preparation of compounds of formula (I) is as shown in scheme 1 below:

2, R, = COgMe, R₂ = H

Wherein, R_¾ and R₂ may be same or different and each is independently selected from H, C0₂Me, CH₂CH2CH3, CH₂OAc, CH₂(CH₂)2CH₃, Ph.

Scheme I: Preparation of compounds of formula (I)

In one embodiment, the present invention provides a novel compound of formula (II) which is used for the preparation of compounds of formula (I);

Formula (II)

Wherein, R-. is selected from CI, NHPMB or N(Ac)PMB.

In preferred embodiment, the compound of formula (II) is l-(3-Chloropent-4-yn-l-yl)-2- ethynyl-3,4,5-trirnethoxybenzene (15), 5-(2-Ethyny 1-3,4, 5-trimethoxyphenyl)-N-(4- methoxybenzyI)pent- l-yn-3-amine ( 17) or N-(5-(2-Etiiynyl-3,4,5-trimethoxyphenyl)pent-l- yn-3-yl)-N-(4-methoxybenzyl)acetamide (18).

In another embodiment, the present invention provides a process for the preparation of novel compounds of formula (II) from 3, 4, 5, trimethoxybenzaldehyde comprising the steps of: a) subjecting 3, 4, 5, trimethoxybenzaldehyde (6) for grignard reaction with A- bromobut-l-ene to afford alcohol (7);

(10) ;

e) subjecting iodo compound (11) of step (d) to sonogashira cross-coupling with trimethylsilylacetylene in the presence of bis(triphenylphosphine)palladium(II) dichloride and copper iodide in dimethylformamide/diethyl amine at temperature ranging from 70 to 90 °C to afford protected compound (12) followed by one pot silyl and acetate deprotection using potassium carbonate as a base in methanol to afford alcohol (13);

f) oxidizing alcohol (13) of step (e) with suitable oxidizing agent to afford aldehyde (14);

g) subjecting aldehyde (14) for asymmetric a-chlorination using suitable chlorinating and oxidizing agent in presence of L-proline and followed by treatment with Ohira- Bestmann reagent (16) with potassium carbonate in methanol to afford the desired compound of formula (II) wherein R¹ is CI; h) reacting compound of formula (II) of step (g) with p-methoxybenzyl amine in presence of suitable base in acetonitrile for the period ranging from 70-80 hrs to afford to afford the desired compound of formula (II) wherein R¹ is -NHPMB; i) protecting acetate group of compound of step (h) by Stirling the reaction mixture comprising compound of step (h) in dichloromethane (CH₂C1₂), NEt₃, dimethyl aminopyridine (DMAP) and acetic anhydride (Ac₂0) for the period in the range of 3-5 h to afford desired compound of formula (II) wherein R¹ is -

N(A< :)PM B The suitable deoxygenating agent in step (b) is triethylsilane (Et₃SiH). The suitable oxidizing agent in step (f) is Dess-Martin periodinane. The suitable chlorinating agent in step (g) is n- chlorosuccinamide (NCS).

The process for the preparation of compounds of formula (II) is stalled with the addition of 4- Bromo- l-butenyl magnesium bromide on commercial available 3, 4, 5, trimethoxybenzaldehyde 6 to get alcohol 7 with 92% yield (Scheme 2), Subsequently, alcohol 7 is treated for deoxygenation with BF₃.Et₂0 and Et₃SiH to afford 8. The compound 8 is subjected for functional manipulation at olefin center like oxidative cleavage to aldehyde followed by reduction and acetate protection of resulting alcohol to afford ester 10 in 70% yield over four steps. The resulting ester 10 is then treated with I₂/CF₃COOAg in CHC1₃, afford iodo compound 1 1 with 85% yield. Now the stage is set for the installation of first alkyne required for cyclotrimerisation. A Sonogashira cross-coupling of alkyne 11 with trimethylsilylacetylene in the presence of PdCl₂(PPh₃)₂ (2 mol %), copper iodide (20 mol%) in DMF/diethyl amine (1 :2) at 80 °C followed by one pot silyl and acetate deprotection using K₂CO₃ as a base in methanol afford alcohol 13 with excellent yields. Incorporation of second alkyne is realized from sequence of 3 steps. Alcohol 13 is oxidized with Dess-Martin periodinane to aldehyde 14. One of the methods for a-chlorination examined, the use of L- proline and n-chlorosuccinamide (NCS) found as the best combination for asymmetric a- chlorination of aldehydes, following the treatment with Ohira-Bestmann reagent 16 with K₂CO₃ in methanol produced compound 15 in 45% yield over 3 steps.

The process for the preparation of compounds of formula (II) is as shown in scheme 2 below:

Scheme 2i Synthesis of Dialkyne 15.

In one embodiment of the present invention, the present invention provides a pharmaceutical composition comprising a compound of formula (I), or a stereoisomer, or ester or pharmaceut cally acceptable salt thereof, and a pharmaceutically acceptable carrier, diluent or excipient.

The pharmaceutical compositions of the invention can be prepared by combining a compound of the invention with an appropriate pharmaceutically acceptable carrier, diluent or excipient known in the art. The excipients or carriers are selected from the group such as diluents, disintegrants, crosslinked polymers, binders, lubricants, coatings layer.

In another embodiment, the present invention relates to administering 'an effective amount' of the 'composition of invention' to the subject suffering from cancer. Accordingly, compound of the invention and pharmaceutical compositions containing them may be administered using any amount, any form of pharmaceutical composition via any route of administration effective for treating the disease. Typical routes of administering such pharmaceutical compositions include, without limitation, oral, topical, transdermal, inhalation, parenteral, sublingual, buccal, rectal, vaginal, and intranasal.

The pharmaceutical compositions can be administered to a subject or patient may take the form of one or more dosage units. The dosage forms can also be prepared as sustained, controlled, modified and immediate dosage forms.

The pharmaceutical compositions of the invention can be prepared by combining a compound of the invention with an appropriate pharmaceutically acceptable carrier, diluent or excipient, and may be formulated into preparations in solid, semi-solid, liquid, such as tablets, capsules, powders, granules, ointments, solutions, injections, gels and microspheres.

The pharmaceutical compositions of the invention are formulated so as to allow the active ingredients contained therein to be bioavailable upon administration of the composition to a patient. Compositions that will be administered to a subject or patient may take the form of one or more dosage units. The dosage forms can also be prepared as sustained, controlled, modified and immediate dosage forms.

In one embodiment, the present invention provides a method for the treating or preventing cancer in a subject in need thereof; comprising administering to the said subject a therapeutically effective amount of the compound of formula (I) or a pharmaceutically acceptable salt thereof.

In another embodiment the present invention provides a method for treating or preventing cancer comprising administering to a subject in need thereof an effective amount of said composition.

In a preferred embodiment the present invention provides a method, wherein the cancer is lung cancer, breast cancer, colorectal cancer, prostate cancer, a leukemia, a lymphoma, non- Hodgkin's lymphoma, skin cancer, a brain cancer, a cancer of the central nervous system, ovarian cancer, uterine cancer, stomach cancer, pancreatic cancer, esophageal cancer, kidney cancer, liver cancer, or a head and neck cancer.

In a preferred embodiment, the compositions of compounds of formula (I) are used as antimitotic agent, anti- microtubule agents.

In a more preferred embodiment, the compositions of compounds of formula (I) shows the cytotoxic effect against cell lines selected from A431 (epidermoid carcinoma), LN229 (brain cancer), HEK293T (control/normal) and SiHa (cervical cancer).

Fig. 1 depicts the graph which shows the cytotoxic effect of molecule (compound 2) on A431 (with IC 50: 128.8452 ^ig/ml), LN229 (with IC 50: 220.0269 .ug/ml), HE 293T (with IC 50: 171.9255 p.g/ml) and SiHa (with IC 50: 488.8137 .ug/ml). Fig. 2 shows the cytotoxic effect of molecule (compound 19) on A431 (with IC 50: 136.62 ^ig/ml), LN229 (with IC 50: 244.81 ^ig/ml), HEK293T (with IC 50: 182.734 μ^πύ) and SiHa (with IC 50: 194.511 ).

Fig. 3 depicts the graph which shows the cytotoxic effect of molecule (compound 20) on A431 (with IC 50: 128.3682 p.g/ml), LN229 (with IC 50: 149.7078 g/ml), HEK293T (with IC 50: 167.3332 μ^πύ) and SiHa (with IC 50: 194.8697 μg/ml).

Fig. 4 depicts the graph which shows the cytotoxic effect of molecule (compound 22) on A431 (with IC 50: 150.4805 μ^πιΐ), LN229 (with IC 50: 195.8868 μξ/ταϊ), HEK293T (with IC 50: 219.9398 μg/ml) and SiHa (with IC 50: 216.9956 μ^ηιΐ).

Fig. 5 shows the cytotoxic effect of molecule (compound 23) on A431 (with IC 50: 161.304), L 229 (with IC 50: 202.105 g/ml), HEK293T (with IC 50: 189.596 μg/ml) and SiHa (with IC 50: 155.583 μg/ml).

Fig. 6 shows the cytotoxic effect of molecule (compound 25) on A431 (with IC 50: 145.36), LN229 (with IC 50: 166.835 μg/rnl), HEK293T (with IC 50: 151.768 μg/mi) and SiHa (with IC 50: 151.52 μ^πύ).

Examples: Following examples are given by way of illustration therefore should not be construed to limit the scope of the invention. Examples:

Example 1: Synthesis of l-(3,4,5-Trimethoxyphenyl)pent-4-en-l-ol (7):

A suspension of Mg (3.2 g, 132.52 mmol) and catalytic iodine (100 mg) in dry THF (350 mL) was treated with 4-bromobut-l-ene (13.5 mL, 132.52 mmol) at 0 °C and the contents were stirred at 25 °C for I h. To this, a solution of the 3,4,5-trimethoxybenzaldehyde 6 (20.0 g, 101.94 mmol) in THF (50 mL) was added slowly at 0 °C and the mixture was stirred for another 2 h at 25 °C. The reaction mixture was quenched with saturated NH₄C1 (200 mL) and extracted with EtOAc (3x300 mL). The combined organic extract was dried ( a₂S0₄), concentrated and the resulting crude residue was purified by silica gel column chromatography (20--→35% EtOAc in pet. ether) afforded 7 (23.7 g, 92%) as a colorless oil. Rf 0.4 (40% EtOAc in pet. ether); Ή NMR (200 MHz, CDC1₃): δ 1.71-1.91 (m, 2H), 2.05- 2.19 (m, 2H), 3.80 (s, 3H), 3.83 (s, 6H), 4.60 (dd, ,/ = 5.8, 7.6 Hz, 1H), 4.95-5.08 (m, 2H), 5.82 (ddt, J = 6.4, 10.2, 17.1 Hz, 1H), 6.53 (s, 2H); ¹³C NMR (50 MHz, CDC1₃): δ 30.1 (t). 38.0 (t), 55.9 (q, 2C), 60.7 (q), 74.1 (d), 102.5 (d, 2C), 114.9 (t), 136.9 (s), 138.1 (d), 140.5 (s), 153.1 (s, 2C) ppm; FIRMS (ESI+) calculated for Ci₄H₂o0₄Na 275.1254; Found 275.1251.

Example 2: Synthesis ofl-(3,4,5-Trimethoxyphenyl)pent-4-en-l-ol (8): To a cooled solution of the alcohol 7 (23.0 g, 91.16 mmol) in anhydrous CH₂C1₂ (400 mL), triethylsilane (18.9 mL, 118.51 mmol) and boron trifluoride diethyl etherate (16.9 mL, 136.74 mmol) was added slowly one by one and stirring was continued at 25 °C for 6 h. The reaction mixture was quenched with saturated NaHC0₃ solution (200 mL) and the aqueous layer was extracted with CH₂CI₂ (2 x 300 mL). The combined organic layer was dried (Na₂S0₄) and concentrated under reduced pressure. Purification of the residue by silica gel column chromatography (10→15% EtOAc in pet. ether) gave 8 (20.3 g, 94 %) as colorless oil. R_f 0.4 ( 15% EtOAc in pet. ether); 1H NMR (200 MHz, CDC1₃): δ 1.70 (quint, J = 7.5 Hz, 2H), 2.09 (q, J = 7.3 Hz, 2H), 2.56 (t, J = 7.3 Hz, 2H), 3.81 (s, 3H), 3.84 (s, 6H), 4.94-5.08 (m, 2H), 5.83 (ddt, J = 6.7, 10.2, 17.1 Hz, 1 H), 6.38 (s, 2H); ^{i 3}C NMR (50 MHz, CDCI₃): δ 30.6 (t), 30.3 (t), 35.7 (t), 55.9 (q, 2C), 60.8 (q), 105.1 (d, 2C), 114.8 (t), 135.8 (s), 138.2 (s), 138.5 (d), 153.0 (s, 2C), ppm; HRMS (ESI+) calculated for Ci₄H₂i0₃ 237.1485, found 237.1483.

Example 3; Synthesis of 4-(3,4,5-Trimethoxyphenyl)butyl acetate (10): To a solution of 8 (20.0 g, 84.63 mmol) in 1,4-dioxane/water (9: 1, 400 mL), Mn0₄ (14.7 g, 93.10 mmol) was added and the contents were stirred at 25 °C for 4h. The reaction mixture was filtered through celite pad and crude was extracted with EtOAc (3 x 300 mL). The combined organic layer was dried (Na₂SC¼), and concentrated under vacuum. The crude was used for next step as such without purification. To a solution of above product in CH₂Cl₂/water (9: 1, 400 mL), Nai0₄ (18.1 g, 84.63 mmol) was added at 25 °C. The reaction mixture was stirred for 2 h. The reaction mixture was partitioned between water and CH₂CI₂ and the aqueous layer was extracted with CH₂C1₂ (2 x 300 mL). The combined organic layer was dried (Na₂S0₄) and concentrated under reduced pressure. The crude was used for next step as such without purification. A solution of above product in methanol (300 mL) was treated with NaBH₄ (3.2 g, 84.63 mmol) at 0 °C. The reaction was stirred for 2 h at 25 °C and quenched with saturated ammonium chloride (200 mL) and extracted with EtOAc (3 x 300 mL). The combined organic extract was dried (Na₂S0₄), concentrated and the resulting crude was used for next step as such without purification. To a cooled solution of above crude in CH₂CI₂ (300 mL), NEt₃ (1 1.8 mL, 84.63 mmol), catalytic DMAP and Ac₂0 (8.0 mL, 84.63 mmol) was added and the contents were stirred at 25 °C for 4h. The reaction mixture was partitioned between water and CH₂C1₂ and the aqueous layer was extracted with CH₂C1₂ (2 x 300 mL). The combined organic layer was dried (Na₂S0 ), and concentrated under vacuum. The resulting crude residue was purified by silica gel column chromatography (10→15% EtOAc in pet. ether) afforded 10 (16.7 g, 70%) as a colorless oil. R_f 0.4 (15% EtOAc in pet. ether); ⁵ H NMR (200 MHz, CDC1₃): δ 1.63-1.70 (m, 4H), 2.04 (s, 3H), 2.54-2.61 (m, 2H), 3.81 (s, 3H), 3.84 (s, 6H), 4.08 (t, J = 6.4 Hz, 2H), 6.38 (s, 2H); ¹³C NMR (50 M Hz, CDC1₃): S 21.0 (q), 27.8 (t), 28.2 (t), 35.9 (t), 56.0 (q, 2C), 60.8 (q), 64.3 (t), 105.1 (d, 2C), 136.0 (s), 137.8 (s), 153.1 (s, 2C), 171.2 (s) ppm; FIRMS (ESI+) calculated for C₁₅H₂₃O₅ 283.1540; Found 283.1535.

Example 4: Synthesis of 4-(2-Iodo-3,4,5-trimethoxyphenyl)butyl acetate (II):

A solution of acetate 10 (7.5 g, 26.56 mmol) in CHCI₃ (150 mL) cooled to 0 °C and treated with CF₃COOAg (7.6 g, 34.53 mmol). The reaction mixture was stirred for 10 min. and then h (8.1 g, 31.88 mmol) was added portion wise to it. The reaction was continued for 5 h at 25 °C and then partitioned between water and CHCI₃ and the aqueous layer was extracted with CH₂G₂ (2 x 100 mL). The combined organic layer was dried ( Na2.SC ) : ) and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (5-→15% EtOAc in pet. ether) to gave iodo compound 11 (9.4 g, 85 %) as colorless syrup. R_f 0.6 (20% EtOAc in pet. ether); ^"!H NMR (200 MHz, CDCI₃): δ 1.62-1.72 (m, 4H), 2.04 (s, 3H), 2.53 (t, J = 7.3 Hz, 2H), 3.84 (s, 6H), 3.85 (s, 3H), 4.11 (t, 7 = 6.1 Hz, 2H), 6.61 (s, IH); ¹³C NMR (50 MHz, CDC1₃): δ 20.9 (q), 26.6 (t), 28.1 (t), 40.5 (t), 56.0 (q), 60.6 (q), 60.8 (q), 64.2 (t), 108.5 (d), 140.2 (s), 140.3 (s, 2C), 152.9 (s), 153.4 (s), 171.1 (s) ppm; HRMS (ESI+) calculated for Ci₅H₂iI0₅ a 431.0326; Found 431.0317.

Example 5: Synthesis of4-(3,4,5-Trimethoxy-2-((trimethylsilyl)ethynyl)phenyl)butyl acetate (12);

The mixture of iodo compound 11 (3.0 g, 7.35 mmol), triniethylsilylacetylene (3.1 mL, 22.05 mmol), PPh₃ (385 mg, 1.4 mmol), Pd(PPh₃)₂Cl₂ (258 mg, 0.37 mmol) and Cul (280 mg, 1.47 mmol) was dissolved in dry DMF (7 mL) and Et₂NH (15 ml) in air tight sealed tube. The reaction mixture was heated at 80 °C for 16 h. Then it was cooled to 25 °C and paititioned between water and EtOAc and the aqueous layer was extracted with EtOAc (3 x 100 mL).

The combined organic layer was dried (Na₂S0₄) and concentrated under reduced pressure. The resulting crude residue was purified by silica gel column chromatography (5→15%

EtOAc in pet. ether) afforded 12 (2.4 g, 86%) as a colorless oil. R_f 0.5 (15% EtOAc in pet. ether); 1H NMR (200 MHz, CDC1 ): δ 0.24 (s, 9H), 1.64-1.71 (m, 4H), 2.03 (s, 3H), 2.68-

2.73 (m, 2H), 3.81 (s, 3H), 3.84 (s, 3H), 3.94 (s, 3H), 4.08 (t, J = 6.0 Hz, 2H), 6.46 (s, 1 H); ^l3C NMR (50 MHz, CDCI₃): δ 0.0 (q, 3C), 21.0 (q), 26.9 (t), 28.4 (t), 34.5 (t), 55.9 (q), 61.0 (q, 2C). 64.4 (t), 99.6 (s), 100.9 (s), 107.8 (d), 109.9 (s), 140.0 (s), 141.5 (s), 153.7 (s), 155.2

(s), 171.2 (s) ppm; HRMS (ESI+) calculated for C₂oH₃j0₅Si 379.1935; Found 379.1931. Example 6; Synthesis of 4-(2-Ethynyl-3,4,5-trimethoxyphenyl)butan-l-ol (13):

To a solution of alkyne 12 (6.0 g, 15.85 mmol) in methanol (200 mL), K₂C0₃ (6.6 g, 47.55 mmol) was added and stirred for 4 h at 25 °C. The reaction mixture was diluted with water and EtOAc and extracted crude by using EtOAc (3 x 100 ml). Then washed with brine, dried (Na₂S0₄) and concentrated under reduced pressure. The purification of residue by silica gel chromatography (30→45% EtOAc in pet. ether) gave alcohol 13 (3.73 g, 89%) as colorless syrup. RfO.3 (40% EtOAc in pel. ether); 1H NMR (200 MHz, CDC1₃): δ 1.62- 1.68 (m, 4H), 2.75 (t, J = 7.3 Hz, 2H ), 3.37 (s, 1H), 3.68 (t, J = 6.0 Hz, 2H), 3.83 (s, 3H), 3.85 (s, 3H), 3.94 (s, 3H), 6.49 (s, 1H); ¹³C NMR (125 MHz, CDCL): δ 26.7 (t), 32.3 (t), 34.2 (t), 55.9 (q), 61.0 (q), 61.2 (q), 62.6 (t), 78.3 (s), 83.3 (d), 107.8 (d), 108.6 (s), 139.9 (s), 141 .9 (s), 153.9 (s), 155.4 (s) ppm; HRMS (ESI+) calculated for C15H21O4 265.1434; Found 265.1435.

Example 7: Synthesis of l-(3~Chioropent-4~yn-l-yi)-2~ethyiiyi-3,4,5-trimethoxybenzene (15):

A solution of alcohol 13 (500 mg, 1.89 mmol) in CH₂C1₂ (20 mL) was treated with Dess- Martin periodinane (962 mg, 2.27 mmol) for 4 h at 25 °C. The reaction mixture was quenched with saturated Na₂S₂0₃ (50 111L) and then with NaHC0₃. The crude was extracted with CH₂CI? (2x50 mL) from aqueous layer. The combined organic extrac was dried (Na₂S0₄), concentrated and the resulting crude residue was used immediately for next step as such without purification. A solution of above product in acetonitrile (20 mL) was reacted with L-proline (65 mg, 0.57 mmol) and n-chlorosuccinimide (252 mg, 1.89 mmol) at 0 °C. The reaction was stirred for 1 h at 25 °C and partitioned between water and EtOAc. The aqueous layer was extracted with EtOAc (2 x 50 mL); the combined organic layer was dried ( a₂S0₄) and concentrated under reduced pressure. The crude was used for next step as such without purification. To a cooled solution of above crude in methanol (50 mL), Ohira- Bestmann reagent (399 mg, 2.08 mmol) and K₂C0₃ (313 mg, 2.27mmol) was added and the contents were stirred at 25 °C for 3 h. The reaction mixture was partitioned between water and EtOAc and the aqueous layer was extracted with EtOAc (2 x 300 mL). The combined organic layer was dried (Na₂S0₄), and concentrated under vacuum. The resulting crude residue was purified by silica gel column chromatography (10→15% EtOAc in pet. ether) afforded 15 (263 mg, 45%) as a colorless oil. R_f 0.6 (15% EtOAc in pet. ether); 1H NMR (200 MHz, CDCI₃): δ 2.27 (q, J = 7.5 Hz, 2H), 2.63 (d, J = 2.4 Hz, 1H), 3.37 (dt, J = 1.1, 8.1 Hz, 2H), 3.40 (s, 1H), 3.83 (s, 3H), 3.85 (s, 3H), 3.95 (s, 3H), 4.47 (dt, J = 2.3, 6.7 Hz, 1 H), 6.52 (s, 1 H); ¹³C NM R (125 MHz, CDCI3): δ 31 .3 (t), 39.0 (t), 47.3 (d), 56.0 (q), 61.0 (q), 61 .3 (q), 74.6 (d), 77.8 (s), 81.7 (s) 84.0 (d), 108.3 (d), 108.9 (s), 139.4 (s), 140.4 (s), 154.0 (s), 155.7 (s) ppm; HUMS (ESI+) calculated for Cj₆H₁₈C10₃ 293.0939; Found 293.0939.

Example 8: Sy thesis of 5-(2-Ethynyl-3,4,5-trimethoxyphenyl)-N-(4- methoxybenzyl)pent-l-yn-3-amine (17):

To a solution of dialkyne 15 (250 nig, 0.85 mmol), j-methoxybenzyl amine (0.17 mL, 1.28 mmol) and Cs₂C0₃ (834 rug, 2.53 mmol) in acetonitrile (15 mL) was added at 25 °C and stirred for 72 h. The reaction mixture was concentrated and the resulting crude material is dissolved in EtOAc (60 mL), washed with water (50 mL), dried (Na₂S0₄) and concentrated in vacuum. The purification of residue by silica gel column chromatography (25→40% EtOAc in pet. ether) gave a!kyne 17 (205 mg, 61%) as yellow oil. R_f 0.3 (40 % EtOAc in pet.); 1H NMR (500 MHz, CDC1₃): δ 1 .90 2.02 (m, 2H), 2.36 (d, J = 2.1 Hz, 1H), 2.86-2.95 (m, 2H), 3.35 (s. I I I ). 3.38 (dt, ../ = 1.8, 6.7 Hz, IH), 3.74 (d, / = 12.5 Hz, 1 H), 3.79 (s, 3H), 3.82 (s, 3H), 3.83 (s, 3H), 3.94 (s, 3H), 3.96 (d, ,/ = 12.8 Hz, IH), 6.50 (s, H i ). 6.85 (d, ,/ = 8.5 Hz, 2H), 7.27 (d, J = 8.5 Hz, 2H); ^j3C NMR (125 MHz, CDC1₃): δ 31.2 (t), 36.3 (t), 48.8 (d), 50.6 (t), 55.3 (q), 56.0 (q), 61 .0 (q), 61.2 (q), 71.9 (d), 78.1 (s), 83.6 (d), 85.2 (s), 108.1 (d), 108.8 (s), 113.8 (d, 2C), 129.5 (d, 2C), 132.0 (s), 140.1 (s), 141.1 (s), 153.9 (s), 155.5 (s), 158.7 (s) ppm; HRMS (ESI+) calculated for C _:J ! > Χ).. 394.2013; Found 394.2012.

Example 9: Synthesis of N-(5-(2-Ethvnvl-3,4,5-trintiethoxvphenyl)pent-l-yn-3-yl)-N-(4- methoxybeBzy amide llS):

To a cooled solution of alkyne 17 (200 mg, 0.51mmoi) in CH₂C1₂ (10 mL), NEt₃ (0.06 mL, 0.61 mmol), catalytic DMAP and Ac₂0 (0.11 mL, 0.76 mmol) was added and the contents were stirred at 25 °C for 4h. The reaction mixture was partitioned between water and CH₂Q₂ and the aqueous layer was extracted with CH₂C1₂ (2 x 300 mL). The combined organic layer was dried (Na₂S0₄), and concentrated under vacuum. The resulting crude residue was purified by silica gel column chromatography (35→50% EtOAc in pet. ether) afforded 18 (206 mg, 93%) as a colorless oil. R/ 0.3 (50% EtOAc in pet. ether); ^lli NMR (500 MHz, CDC1₃): δ 1.90-1.96 (m, 2H), 1.98 (s, 3H), 2.29 (d, J = 2.4 Hz, I H), 2.71-2.77 (m, I H), 2.84-2.90 (m, IH), 3.37 (s, IH), 3.78 (s, 3H), 3.82 (s, 3H), 3.83 (s, 3H), 3.94 (s, 3H), 4.53 (d, J = 17.1 Hz, I H), 4.68 (d, / = 17.1 Hz, IH), 5.58 (dt, 7 = 2.1 , 8.8 Hz, IH), 6.47 (s, I H), 6.86 (d, J = 8.5 Hz, 2H), 7.19 (d, J = 8.9 Hz, 2H); ¹³C NMR (125 MHz, CDC1₃): δ 22.5 (q), 31.3 (t), 34.7 (t), 46.7 (d), 48.5 (t), 55.3 (q), 56.0 (q), 61.0 (q), 61.3 (q), 73.5 (d), 78.1 (s), 81 .7 (d), 83.7 (s), 107.9 (d), 108.7 (s), 114.1 (d, 2C), 127.5 (d, 2C), 129.9 (s), 140.1 (s), 140.4 (s), 154.0 (s), 155.5 (s), 158.8 (s), 171.3 (s) ppm; FIRMS (ESI+) calculated for C24H28NO4

436.2118; Found 436.2115.

Example 10: General Procedure for Alk ne [2 + 2 + 2]-Cydotrimerization.

The diyne 18 (1 equiv) and alkyne (2.5 equiv) were placed in a screw-capped pressure tube and dissolved in anhydrous toluene (2 mL), which was then evacuated and back-filled with argon. To the reaction vessel, CpCo(CO)? (20 mol %) was added. The solution was then stirred under light (200 W) until consumption of the starting material. The reaction mixture was cooled to 25 °C and the crude filtered through Celite pad and concentrated, and the crude product was subjected to N-PMB group deprotection. A solution of the above crude product in CH₂Cl₂/trifluoroacetic acid (1:2, 6 mL) was stirred at 25 °C until the complete disappearance of the starting compound, as indicated by TLC. After completion, the solvent was evaporated under reduced pressure and the residue was subjected to silica gel column chromatography (230-400 mesh) to afford the corresponding cyelotrimerization product.

Example 11: Synthesis of compound (2):

The alkyne 18 (30 mg, 0.069 mmol) and methyl propiolate (0.02 mL, 0.207 mmol) was placed in a screw cap pressure tube and dissolved in anhydrous toluene (2 mL), which was then evacuated and back filled with argon. To the reaction vessel CpCo(CO)₂ (0.69 mL, 0.2 M, 20 mol%) was added. The solution was then stirred under light (200 W) for 12 h. The reaction mixture was cooled to 25 °C. The crude filtered through Celite pad, solvent was evaporated and the crude was subjected to further reaction. The above crude was treated with Ci^C /trifluoroacetic acid (1:2, 6 mL) and the reaction mixture was stirred for 12 h at 25 °C. The solvent was evaporated on rotavapor and residue was subjected to column chromatography by using silica gel (230-400 mesh) and pet. ether/EtOAc (50→75%) gave two regioisomers (2:1) proportion. The required compound 2 (7 mg, 24%) was obtained as white solid. R_f 0.2 (70% EtOAc in pet. ether); 1H NMR (500 MHz, CDCI3): δ 1.84-1.85 (m, 1H), 2.10 (s, 3H), 2.24-2.27 (m, 1H), 2.43-2.47 (m, 2H), 3.54 (s, 3H), 3.91 (s, 3H), 3.93 (s, 3H), 3.94 (s, 3H), 4.87 (br s, IH), 6.10 (br s, 1H), 6.59 (s, IH), 7.57 (d, J = 7.9 Hz, IH), 7.97-7.99 (m, 2H); ⁱ³C NMR (125 MHz, CDC1₃): δ 23.2 (q), 30.2 (t), 39.3 (t), 49.1 (d), 52.0 (d), 55.9 (q), 61.1 (q, 2C), 107.6 (d), 123.5 (d), 123.8 (s), 127.5 (d), 128.5 (s), 130.2 (d), 134.5 (s), 139.2 (s), 139.4 (s), 141.2 (s), 151.1 (s), 153.2 (s), 167.1 (s), 169.5 (s) ppm; HRMS (ESI+) calculated for C₂₂H₂₆N0₆ 400.1755 ; Found 400.1751. Example 12: Synthesis of (HaR)-Methyl 5-acetamido-9,10,l l-trimethoxy-6,7-dihydro- 5H-dibenzo[a,c][7]annulene-2-carboxylate (19):

The another regioisomer 19 (15 mg, 52%) was obtained as white solid. R_f 0.3 (80% EtOAc in pet. ether); Ή NMR (400 MHz, CDC1₃): δ 1.80-1.86 (m, 1 H), 2.07 (s, 3H), 2.23-2.30 (ni, I H), 2,45-2.50 ( m. 21 1 ). 3.57 (s, 3H), 3.91 (s, 3H), 3.92 (s, 3H), 3.94 (s, 3H), 4.83-4.89 (m, 1 H), 5.86 (d, J = 7.4 Hz, IH), 6.58 (s, 1H), 7.36 (d, ,/ = 7.8 Hz, 1H), 8.00 (d, / = 7.8 Hz, 1H), 8.16 (d, J = 1.5 Hz, 1H); ⁱ³C NMR (100 MHz, CDC1₃): δ 23.3 (q), 30.3 (t), 39.5 (t), 49.5 (d), 52.1 (d), 56.1 (q), 61.2 (q), 61.3 (q), 107.6 (d), 122.4 (d), 124.0 (s), 128.4 (d), 128.6 (s), 131.5 (d), 134.5 (s), 134.7 (s), 141.4 (s), 144.2 (s), 151.3 (s), 153.1 (s), 167.2 (s), 169.2 (s) ppm; HRMS (ESI+) calculated for C -i i._:;,Ni>_(> 400.1755; Found 400.1750.

Example 13: Synthesis of N-((llaR)-9,10,ll-Trimethoxy-6,7-dihydro-5H- dibenzora,c][7]annulen-5~yl)acetamide (20):

The reaction was carried out similar to general procedure for trimerization with alkyne 18 (40 mg, 0.092 mmol) and acetylene. The analogue 20 (24 mg, 77%) was obtained as white solid. Rf 0.3 (70% EtOAc in pet. ether); ^lU N (400 MHz, CDC1₃): δ 1.76-1.83 (m, 1H), 2.05 (s, 3H), 2.29-2.35 (m, IH), 2.40-2.47 (m, 2H), 3.51 (s, 3H), 3.89 (s, 3H), 3.92 (s, 3H), 4.80- 4.86 (m, I H), 5.86 (d, J = 6.9 Hz, I H), 6.56 (s, I H), 7.27-7.28 (m, IH), 7.30-7.33 (m, 2H), 7.46-7.50 (m, IH); ^¾3C NMR (125 MHz, CDC1₃): δ 23.3 (q), 30.5 (t), 39.7 (t), 49.3 (d), 56.1 (q), 61 .1 (q), 61 .3 (q), 107.5 (d), 122.0 (d), 124.9 (s), 126.5 (d), 127.2 (d), 130.2 (d), 134.4 (s), 134.7 (s), 138.8 (s), 141.3 (s), 151.2 (s), 152.7 (s), 169.4 (s) ppm. HRMS (m/z) \ M + H] calculated for C₂₀H₂₄O₄N 342.1700, found 342.1693.

Example 14: Synthesis of Methyl (llaR)-5-acetamido-2-butyl-9,ll),ll-tri^methoxy-6,7- dihydro~5H-dibenzo[a,c][7]aH-iiuieHe-3-carboxylate (21):

The reaction was carried out similar to general procedure for trimerization with alkyne 18 (60 mg, 0.138 mmol) and Methyl 2-heptynoate. The analogue 21 (21 mg, 33%) was obtained as pale yellow oil. R_f 0.3 (70% EtOAc in pet. ether); 1H NMR (400 MHz, CDC1₃): δ 0.89-0.94 (m, 3H), 1.38 (q, / = 7.4 Hz, 2H), 1.56-1.60 (m, 2H), 1.77-1.84 (m, IH), 2.11 (s, 3H), 2.25- 2.30 (m, IH), 2.41 -2.48 (m, 2H), 2.88-2.94 (m, IH), 2.97-3.02 (m, IH), 3.52 (s, 3H), 3.89 (s, 3H), 3.91 (s, 3H), 3.93 (s, 3H), 4.79-4.86 (m, IH), 6.06 (d, 7 = 8.3 Hz, I H), 6.56 (s, IH), 7.40 (s, IH), 7.72 (s, IH); ⁱ³C NMR (100 MHz, CDC1₃): δ 14.0 (q), 22.7 (t), 23.2 (q), 30.5 (t), 33.9 (t), 34.0 (t), 39.4 (t), 49.1 (d), 51.9 (q), 56.1 (q), 61.2 (q), 61.3 (q), 107.8 (d), 123.9 (s), 124.5 (d), 128.0 (s), 133.1 (d), 134.7 (s), 136.1 (s), 138.3 (s), 141.4 (s), 143.0 (s), 151.3 (s), 152.2 (s), 168.5 (s) ppm. HRMS (m/z) [M + H]⁺ calculated for C₂6H₃₄0₆N 456.2381 , found 456.2372.

Example 15: Methyl (llaR)-5-acetamido-3-butyl-9,10,ll-trimethoxy-6,7-dihydro-5H- dibenzo[a,c][7]-annulene-2-carboxylate (22):

The reaction was carried out similar to general procedure for trimerization with alkyne 18 (60 mg, 0.138 mmol) and Methyl 2-heptynoate. The analogue 22 (21 mg, 49%) was obtained as pale yellow oil. 0.4 (70% EtOAc in pet. ether); ^!H NMR (400 MHz, CDC1₃): δ 0.95 (t, J = 7.3 Hz, 3H), 1.42 (q, J = 7.3 Hz, 2H), 1 .60-1 .63 (m, 2H), 1 .76-1 .83 (m, 1H), 2.06 (s, 3H), 2.24-2.30 (m, 1H), 2.43-2.46 (m, 2H), 2.93-3.02 (m, 2H), 3.54 (s, 3H), 3.86 (s, 3H), 3.89 (s, 3H), 3.92 (s, 3H), 4.84 (quint, J = 7.3 Ηζ, ΙΗ), 5.81 (d, J = 8.1 Hz, 1H), 6.54 (s. 1H). 7.09 (s, 1 H), 7.99 (s, 1H); °C NMR (125 MHz, CDCI₃): δ 14.1 (q), 22.9 (t), 23.4 (q), 30.4 (t), 34.0 (I), 34.4 (t), 39.6 (t), 49.2 (d), 51.8 (q), 56.1 (q), 61.2 (q). 61.3 (q), 107.6 (d), 124,0 (s), 124.7 (d), 127.6 (s), 131.9 (s), 132.5 (d), 134.6 (s), 141.3 (s), 142.8 (s), 143.7 (s), 151.3 (s), 152.9 (s), 168.1 (s), 169.2 (s) ppm. HRMS (m/z) [M + H]⁺ calculated for C₂6H3₄0₆N 456.2381, found 456.2371.

Example 16: Synthesis of Dimethyl (llaR)-5-acetamido-9,10,l l-trimethoxy-6,7-dihydro- 5H-dibenzo[a,c][7]annulene-2,3-dicarboxylate (23):

The reaction was carried out similar to general procedure for trimerization with alkyne 18 (40 mg, 0.092 mmol) and dimethyl acetylenedicarboxvlate. The analogue 23 (34 mg, 81%) was obtained as white solid. R_f 0.3 (80% EtOAc in pet. ether); ⁵ H NMR (400 MHz, CDC1₃): δ 1.84-1.91 (m, 1H), 2.09 (s, 3H), 2.25-2.30 (m, 1H), 2.43-2.53 (m, 2H), 3.59 (s, 3H), 3.93 (s, 6H), 3.95 (s, 6H), 4,86-4.92 (m, 1H), 6.01 (d, J = 7.8 Hz, 1H), 6.60 (s, 1H). 7.65 (s, 1H). 7.90 (s, 1H); ¹³C NMR (100 MHz, CDC1₃): δ 23.2 (q), 30.2 (t), 39.4 (t), 49.4 (d), 52.6 (q), 52.7 (q). 56.1 (q). 61.3 (q). 61.4 (q). 107.8 (d), 123.2 (s), 123.3 (d), 130.2 (s), 130.4 (s), 131.1 (d), 134.6 (s), 137.7 (s), 141.5 (s), 142.4 (s), 151 .3 (s), 153.7 (s), 168.0 (s, 2C), 168.6 (s) ppm. HRMS (m/z) [M + Hf calculated for C_:. J ! _.·,;( )_SN^' 458.1809. found 458.1802.

Example 17: Synthesis of (5-Acetamido-9,10,ll-trimethoxy-6,7-dihydro-5H- dibenzo[a,c] [7]annulene-2,3-diyl)bis(me-thylene) diacetate (24) : The reaction was carried out similar to general procedure for trimerization with alkyne 18 (40 mg, 0.092 mmol) and ester of butyne diol. The analogue 24 (31 mg, 69%) was obtained as white solid. 0.2 (80% EtOAc in pet. ether); 1H NMR (400 MHz, CDCI₃): δ 1.78-1.85 (m. i l l ). 2.08 (s, 6H), 2.10 (s, 3H), 2.29-2.32 (m, 1 1 1 ). 2.41-2.48 (m, 2H), 3.54 (s, 3H), 3.89 (s, 3H), 3.91 (s, 3H), 4.78-4.84 (m, IH), 5.21 (s, 4H), 5.95 (d, / = 7.8 Hz, 1H), 6.56 (s, 1H), 7.25 (s, IH), 7.53 (s, 1H); ^j3C NMR (125 MHz, CDC1₃): δ 21.0 (q), 21.1 (q), 23.2 (q), 30.4 (t), 39.5 (t), 49.3 (d), 56.1 (q), 61.2 (q, 2C), 63.7 (t), 64.2 (t), 107.6 (d), 123.9 (s), 124.4 (d), 131.8 (d), 133.0 (s, 2C), 134.7 (s), 135.1 (s), 139.3 (s), 141.3 (s), 151.2 (s), 153.1 (s), 170.0 (s), 170.8 (s), 170.9 (s) ppm; Ή NM R (400 MHz, Acetone-d₆): δ 1 .95-1 .96 (m, 4H), 2.06- 2.07 (m, 6H), 2.15-2.22 (m, H I ). 2.30-2.38 (m, 1H), 2.53-2.57 (m, IH), 3.59 (s, 3H), 3.85 (s, 3H), 3.89 (s, 3H), 4.75-4.80 (m, 1 H), 5.19-5.26 (rn, 4H), 6.79 (s, IH), 7.48 (s, 2H), 7.73 (d, / = 8.1 Hz, IH); ^{i 3}C NMR (100 MHz, Acetone-d₆): δ 20.9 (q, 2C), 22.9 (q), 31.2 (t), 39.9 (t), 49.4 (d), 56.4 (q), 61.1 (q), 61.4 (q), 64.2 ((), 64.6 (t), 109.0 (d), 125.1 (s), 125.5 (d), 132.1 (d), 133.7 (s), 134.3 (s), 135.8 (s), 136.1 (s), 142.3 (s), 151.9 (s), 154.3 (s), 171.0 (s), 171.0 (s), 171.1 (s) ppm; HRMS (ESI+) calculated for C₂6H₃iNO_sNa 508.1942: Found 508.1941.

Example 18: Synthesis of N-((l laR)-9,10,ll-Trimethoxy-2,3-dipropyl-6,7-dihydro-5H- dibenzo[a,c] f ^'7]annu len-5- l)-acetamide (25) :

The reaction was carried out similar to general procedure for trimerization with alk ne 18 (40 mg, 0.092 mmol) and 4-Octyne. The analogue 25 (28 mg, 72%) was obtained as white solid. R_f 0.3 (60% EtOAc in pet. ether); ^jH NMR (400 MHz, CDCi₃): δ 0.94-1.02 (m, 6H), 1.61 - 1.65 (m, 5H), 2.05 (s, 3H), 2.39-2.44 (m, 2H), 2.49-2.55 (m, IH), 2.59-2.65 (m, 4H), 3.50 (s, 3H), 3.88 is, 3H), 3.91 (s, 3H), 4.77-4.84 (m, IH), 5.78 (d, 7 = 8.6 Hz, I H), 6.54 (s, IH), 6.95 (s, I H), 7.27 (s, IH): °C NMR (125 MHz, CDC1₃): δ 14.1 (q), 14.4 (q), 23.5 (q), 24.3 (I), 24.4 (t), 30.7 (t). 34.4 (t), 35.2 (t), 40.0 (t), 48.9 (d), 56.1 (q), 61.0 (q), 61.3 (q), 107.6 (d), 122.5 i d ). 125.2 (s), 131.0 (d), 131.6 (s), 134.8 (s), 136.0 (s), 136.3 (s), 138.4 (s), 139.2 (s), 151.3 (s), 152.4 (s), 169.0 (s) ppm; HRMS (ESI+) calculated for C₂6H₃6NO₄ 426.2639; Found 426.2633.

Example 19: Methyl (llaR)-5-acetamido-9,10,ll-trimethoxy-3-phenyl-6,7-dihydro-5H- dibenzo a,e] [7]-annulene-2-carboxylate (26) :

The reaction was carried out similar to general procedure for trimerization with alkyne 18 (60 mg, 0.138 mmol) and Methyl 3-phenylpropiolate. The analogue 26 (39 mg, 62%) was obtained as pale yellow oil. R 0.3 (60% EtOAc in pet. ether); ¹H NM R (400 MHz, CDCI₃): δ L78- 1.84 (m, IH), 2.02 (s, 3H), 2.32-2.36 (m, IH), 2.42-2.50 (m, 2H), 3.63 (s, 3H), 3.64 (s, 3H), 3.90 (s, 3H), 3.93 (s, 3H), 4.87-4.93 (m, I H), 5.81 (d, J = 8.1 Hz, I H), 6.57 (s, I H), 7.22 (s, 1H),7.34-7.41 (m, 5H), 7.97 (s, IH); ¹³C NMR (125 MHz, CDC1₃): δ 23.3 (q), 30.4 (t), 39.7 (t), 49.3 (d), 51.9 (q), 56.1 (q), 61.2 (q), 61.3 (q), 107.7 (d), 123.7 (s), 124.8 (d), 127.2 (d), 128.0 (d, 2C), 128.5 (d, 2C), 128.9 (s), 131.9 (d), 133.6 (s), 134.6 (s), 141.3 (s), 141.4 (s), 141.5 (s), 142,4 (s), 151.3 (s), 153.1 (s), 168.8 (s), 169.4 (s) ppm. HRMS (m/z) [ M + H]⁺ calculated for Γ.>Π Μ ^' 476.2068, found 476.2061.

Example 20: Biological Activity:

The new compounds were tested agains four differen cell lines. The details are as follows. MTT assay for cell viability and proliferation

Harvesti g and seedi g cells-

1. Harvest cells, count the cells and adjust the concentration of the cell suspension, (cell concentration: ceils/ml).

2. Seed ΙΟΟμΙ of 7000eells/well.

3. Incubate the cells for 18 hours.

4. Addition of different concentrations of ding and detection of cytotoxic activity after 24hrs and 48hrs using the MTT salt.

Finally, crystals were dissolved using DMSO and absorbance was taken at 570nm in a multimode plate reader.

Concentrations of drug(s) taken for activity testing:

· 2^g/ml,

® 50ug/ml and

® lOOug/ml

Cell lines tested and range of ICso ijig ml) values:

* A431 = 120 --- 170

· LN229 = 140 - 250

* HEK293T = 150 - 220

* SiHa = 150 - 490

MTT cytotoxicity assay was performed for estimation of dosages, and determination of bioactivity of compounds. MTT assay, which is based on formation of formazan crystals upon addition of MTT salt, indirectly represents cell viability as reduction of MTT can only occur in metaboiicaily active cells. The formazan crystals were dissolved in isopropanol which gives purple color and the intensity of color directly represent cell vibility w.r.t control cells. In treatment group, cells were incubated with NCL molecules and cytotoxic potential of all three molecules were measured after 48 hours and dose response curves were made as shown below by reading the absorbance of purple color at 570nm in a microplate reader. Following graph shows cytotoxic effect of three molecules (such as NCL 362, 363 and 364) on 4 cell lines obtained from National Centre for Cell Science, National Cell Repository, Pune, India and maintained in our in-house R&D unit for a brief period of time during the assay. Cell lines are A431 (epidermoid carcinoma), LN229 (brain cancer), HEK293T (control/normal) and SiHa (cervical cancer).

Advantages of the invention:

1. The process steps are reduced compared to prior art

2. Novel intermediates are formed which are used for the preparation of library of compounds

3. Simple, cost-effective and easy to operate process

4. Improved yield, Cheap starting material

5. Catalytic amount of catalyst used for reaction

Claims

WE CLAIM;

1. A tricyclic compound of formula I);

Formula (I)

wherein;

Ri and R₂ may be same or different and each is independently selected from the group consisting of C0₂Me, Π Ί Η7Η_Λ CH₂OAc, CH₂(CH₂)2CH₃ or Ph;

or a pharmaceutically acceptable salt, solvate or hydrate thereof.

2. The compound as claimed in claim 1, wherein said tricyclic compound of formula (I) is selected from Methyl (l laR)-5-acetamido-2-butyl-9,10,l l-trimetlioxy-6,7- dihydro-5H-dibenzo[a,c][7]an-nulene-3-carboxylate (21), Methyl (l laR)-5- acetamido-3-butyl-9,10,l l -trimethoxy-6,7-dihydro-5H-dibenzo[a,cJ[7]-annulene-2- carboxylate (22), Dimethyl (l laR)-5-acetanddo-9,10,l l-trimethoxy-6,7-dihydro-5H- dibenzo[a,c][7]annulene-2,3-dicarboxylate (23), (5-Acetamido-9,1.0,l l-trimethoxy- 6,7-dihydro-5H-dibenzo[a,c][7]annulene-2,3-diyl)bis(me-thylene) diacetate (24), N-

yl)-acetamide (25) or Methyl (l laR)-5-acetamido-9,10,l l-trimethoxy-3-phenyl-6,7- dihydro-5H-dibenzo[a,c][7]-annulene-2-carboxylate (26),

3. A process for the preparation of tric clic compound of formula (I);

Formula (I)

wherein, R_\ and R₂ may be same or different and each is independently selected from the group consisting of H, C0₂Me, CH₂CH₂CH₃, CH₂OAc, H CH^CH or Ph, comprising the steps of:

a) reacting dialkyne (15) with p-methoxybenzyl amine in presence of suitable base in acetonitrile for the period ranging from 70 to 80 hrs to afford an alkyne (17); b) protecting acetate group of the alkyne (17) compound of step (a) by stirring the reaction mixture comprising alkyne (17) in dichloromethane, Triethylamine (NEt₃), dimethyl-aminopyridine and acetic anhydride for the period in the range of 3 to 5 hrs to afford an acetamide (18);

c) reacting the acetamide (18) of step (b) with alkyne in presence of cyclopentadi- enylcobalt dicarbonyi under light for the period in the range of 10 to 12 hrs to afford mixture of regioisomers followed by subjecting said mixture to deprotection by using / memo xy benzyl amine and trifluoroacetic acid/Dichloromethane (CH₂CI₂) to afford desired compound of formula (I).

4. The process as claimed in claim 3, wherein said process steps (a) and (b) are carried out at temperature in the range of 25 to 30°C.

5. The process as claimed in claim 3, wherein said base in step (a) is selected from caesium carbonate or calcium carbonate.

6. The process as claimed in claim 3, wherein said alkyne in step (c) is selected from methyl propiolate, acetylene, Methyl 2-heptynoate, dimethyl acetylenedicarboxylate, ester of butyne diol, 4-Octyne or Methyl 3-phenylpropiolate.

7. A compound of formula (II

Formula (II)

wherein, R¹ is selected from the group consisting of CI, -NHPMB or -N(Ac)PMB.

8. The compound as claimed in claim 7, wherein said compound of formula (II) is l-(3-

Chloropent-4-yn-l-yl)-2-ethynyl-3,4,5-trimethoxybenzene (15), 5-(2-Ethynyl-3,4,5- (rimethoxyphenyl)-N-(4-methoxybenzyl)pent-l-yn-3-amine (17) or N-(5-(2-Ethynyl- 3,4,5-trimethoxyphenyl)pent-l-yn-3-yl)-N-(4-methoxybenzyl)acetaiTiide (18).

9. A process for the preparation of compounds of formula (II) as claimed in claim 7, wherein said process comprises the steps of:

b) deoxygenating alcohol (7) of step (a) with suitable deoxygenating agent in presence of boron trifluoride diethyl etherate to afford alkene (8); c) subjecting alkene compound of step (b) for oxidative cleavage to afford aldehyde

(10) ;

d) treating ester (10) of step (c) with Iodine/silver trifluoroacetate in chloroform to afford iodo compound ( 11 );

e) subjecting iodo compound (11) of step (d) to sonogashira cross-coupling with trimethylsilylaeetylene in the presence of bis(triphenylphosphine)palladium(II) dichloride and copper iodide in dimethylformamide/diethyl amine at temperature ranging from 70 to 90 °C to afford protected compound (12) followed by one pot silyl and acetate deprotection using potassium carbonate as a base in methanol to afford alcohol (13);

h) reacting compound of formula (II) of step (g) with -methoxybenzyl amine in presence of suitable base in acetonitrile for the period ranging from 70-80 hrs to afford the desired compound of formula (II) wherein R¹ is -NHPMB; and i) protecting acetate group of compound of step (h) by stirring the reaction mixture comprising compound of step (h) in dichloromethane (CH₂C1₂), Triethylamine (NEt₃), dimethylaminopyridine (D AP) and acetic anhydride (Ac₂0) for the period in the range of 3-5 h to afford desired compound of formula (II) wherein R¹ is -N(Ac)PMB.

10. The process as claimed in claim 9, wherein, said deoxygenating agent in step (b) is triethylsilane (Et₃SiH); and said oxidizing agent in step (f) is Dess-Martin periodinane; and said chlorinating agent in step (g) is «-chlorosuccinamide ( CS).

11. A pharmaceutical composition comprising a compound of formula (I) as claimed in claim 1 , or a stereoisomer, or ester or pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable earner, diluent or excipient.

12. A meihod for treating or preventing cancer in a subject in need thereof; comprising administering to the said subject a therapeutically effective amount of the compound of formula (I) as claimed in claim 1 or a pharmaceutically acceptable salt thereof. The method as claimed in claim 12, wherein the cancer is lung cancer, breast cancer, colorectal cancer, prostate cancer, a leukemia, a lymphoma, non-Hodgkin's lymphoma, skin cancer, a brain cancer, a cancer of the central nervous system, ovarian cancer, uterine cancer, stomach cancer, pancreatic cancer, esophageal cancer, kidney cancer, liver cancer, or a head and neck cancer.