RU2276150C2 - Method for preparing selenopyrilium salts - Google Patents

Abstract

FIELD: chemical technology.

SUBSTANCE: invention relates to the improved method for preparing selenopyrilium salts by interaction of 1,5-diketones with hydrogen selenide that is prepared in dissolving zinc selenide in mixture of acetic acid, hydrogen bromide and diethyl ether. The reaction medium is prepared by addition of acetic acid bromoanhydride to mixture of diethyl ether and hydrogen bromide an aqueous solution. The following indices of compounds are given below as, name, empirical formula, melting point and the yield of the end product, %, respectively: 2,4,6-triphenylselenopyrilium bromozincate, C₂₃H₁₇SeZnBr₃, 256-258°C, 75; 2,6-diphenyl-4-(p-methoxyphenyl)-selenopyrilium bromozincate, C₂₄H₁₉SeOZnBr₃, 247-252°C, 71; 2,6-diphenyl-4-methylselenopyrilium bromozincate, C₁₈H₁₅SeZnBr₃, 205-207°C, 68. All prepared salts have been converted to the corresponding perchlorates. Method provides excluding the use of gaseous hydrogen selenide.

EFFECT: improved preparing method.

2 cl, 3 ex

Description

I. Scope

Salts of selenopyrilia and their derivatives can be used as materials for optoelectronics, intermediates of organic synthesis, drugs, etc. [SU 1447824, B.I. - 1988. - No. 48; SU 1703649 B.I. - 1992. - No. 1; Babenko V.A., Uncle G.G., Kudinova M.A. et al. // Quantum Electronics. - 1980.- t.7. - S. 1796-1802; Nelen M.I., Simard T.P., Davies Sh.R .... // J.Med.Chem. - 1999 .-- vol. 42. - P.3953-3964].

II. State of the art

A number of methods for the synthesis of salts of selenopyrilium are known: using gaseous selenium hydrogen (MPC 0.1 mg / m ³ [Harmful substances in industry T.3. Inorganic and organorganic compounds (edited by N. Lazarev) // Len., Chemistry ". - 1977. - 607 S.]) at different stages of the reaction [Kudinova MA, Krivun SV, Tolmachev A.I. // HCG. - 1973. - No. 6. - S.857-858; SU 1051089 B.I. - 1983. - No. 40; Kharchenko V.G., Drevko B.I. // ZhORKh - 1982. - vol. 18, no. 12. - S.2595-2597; Kharchenko V.G., Drevko B.I. // HGS-1984. - No. 9. - S.1283-1284; Kharchenko V.G., Drevko B.I. // HGS-1984. - No. 12. - S.1634-1637] multistage synthesis based on selenopyrones [Nelen MI, Simard TP, Davies Sh.R .... // J.Med.Chem. - 1999 .-- vol. 42. - P.3953-3964], which themselves are obtained in several stages using lithium superhydride [Detty MR, Murray BJ, Seidberg MD //J.Org. Chem. - 1982. - vol. 47. - P.1968-1969].

The most acceptable method is the synthesis of salts of selenopyrilium, which is based on the interaction under conditions of acid catalysis of arylaliphatic or “seven-cyclic” 1,5-diketones with hydrogen sulfide obtained directly in the reaction medium from zinc selenide [SU 1816762 B.I. - 1993. - No. 19; Drevko B.I., Fomenko L.A., Smushkin M.I., Zhukov O.I., Kharchenko V.G. // HGS-1994. - No. 4. - S.569].

The disadvantage of this method was the difficulty of obtaining 10-13 N solutions of HCl in alcohols. These solutions were prepared for many hours by saturating absolute alcohols with gaseous hydrogen chloride with constant monitoring of the process of saturation of the medium by titration.

III. SUMMARY OF THE INVENTION

The aim of this invention is to create a new method for the synthesis of salts of selenopyrilium, which would not be associated with the use of gaseous selenium hydrogen and did not require the laborious preliminary saturation of absolute alcohol with gaseous reagents. This can be achieved if a concentrated aqueous solution of hydrogen bromide produced by the industry (8-8.4 N) is mixed with diethyl ether and acetic bromide, taken in quantities necessary for complete removal of water. The reaction of acetic acid bromide with water proceeds rapidly, with the release of heat, so cooling is required. As you know, zinc halides are poor, and hydrogen halides are not soluble enough in acetic acid [Kogan VB, Fridman VM, Kararov VV Solubility Guide. - M.: Publishing House of the Academy of Sciences of the USSR. - 1961.Vol. 1. - book 1], therefore, ether was added to the reaction mixture, which eliminated these disadvantages.

Thus, the system was obtained: CH ₃ COOH / HBr / Et ₂ O.

In this reaction medium, the dissolution of zinc selenide with the release of hydrogen selenide was easily passed, and the rate of formation of hydrogen selenide did not exceed the rate of its binding to organo-selenium compounds. As a result of the reaction, disproportionation products of intermediate formed selenopyranes, a mixture of selenopyrilium salts and selenocyclohexanes, were obtained.

The reaction progress and the individuality of the obtained compounds were monitored by TLC on Silufol UV-254 plates in systems: hexane - ether - chloroform (3: 1: 1) and hesane - ether (6: 1, 10: 1, 25: 1), the developer - pairs of iodine.

The reaction medium was not isolated from exposure to atmospheric oxygen, which led to the process of salt formation by oxidation of the intermediate selenopyranes (in addition to the disproportionation reaction) [Drevko BI, Suchkov MA, Vetkin DO, Evdoshenko RV, Kharchenko V.G. // Sat scientific Proceedings, Saratov, publishing house of SSU, 2000, pp. 59-60], therefore, the yields of salts of heteroaromatic cations were higher than the corresponding disproportionation of 66.6%. Therefore, the reaction partially proceeded according to the scheme:

All salts obtained were transferred to the corresponding perchlorates (or tetrafluoroborates) by the method described in [SU 1816762, B. I. - 1993. - No. 19].

To fully illustrate the invention, specific synthesis techniques are provided.

Example 1

Preparation of 2,4,6-Triphenylselenopyrilium (IV) Bromine

To a mixture of 5 ml of concentrated hydrobromic acid and 20 ml of diethyl ether with vigorous cooling, acetic bromohydride is added dropwise in the amounts necessary to bind all the water entering the reaction system (usually ~ 17 ml). 1.64 g (0.005 mol) of 1,3,5-triphenylpentanedione-1,5 (I) and 0.87 g (0.006 mol) of zinc selenide are added to the resulting solution with stirring. The reaction mixture was stirred until complete disappearance of the starting diketone by TLC (~ 0.5 hour), then the precipitated selenopyrilium salt was filtered off, washed with dry ether (3 × 3 ml), dried, and 1.14 g (33.6%) of IV were obtained. 9 ml of diethyl ether and 17 ml of diisopropyl ether are added to the mother liquor and additional insignificant amounts of salt are isolated after 24 hours, which are treated in the same way and 0.36 g (3.9%) are obtained. 65 ml of water is added to the mother liquor, a precipitate forms, which is separated and 1.05 g (31%) of IV is obtained, which is largely contaminated with various impurities (if necessary, 20-25% of the corresponding selenacyclohexane can be isolated from the ether solution) . _Mp = 256-258 ° C. Yield 2.55 g (75%). ₁ H NMR spectrum (CF ₃ COOD / (CD ₃ ) ₂ SO - 1: 1) δ ppm: 8.62 (s, 2H, cat.); 7.28-7.73 (m, 15H, Ph). The estimated gross formula of C ₂₃ H ₁₇ SeZnBr _{3 is} not preserved upon recrystallization and gradually transforms into the C ₂₃ H ₁₇ SeBr · 0.5ZnBr ₂ form; therefore, the salt was identified through the corresponding perchlorates.

0.68 g (0.001 mol) of Bromozincate IV is dissolved in 10 ml of 57% perchloric acid when heated in a boiling water bath. The homogeneous solution is cooled to room temperature, the precipitated crystals are filtered off, washed with dry ether (after adding ether to the mother liquor, a small amount of X crystals precipitate which are filtered off), and dried. Obtain 0.4 g (85%) of 2,4,6-triphenylselenopyrilium perchlorate (X), mp 169-197 ° C. Lit. mp 169-197 ° C [Kudinova M.A., Krivun S.V., Tolmachev A.I. // HCG. - 1973. - No. 6. - S.857-858]. A sample of mixing with a reliable sample [SU 1816762 B.I. - 1993. - No. 19] depression of the melting temperature is not given.

When using the salt of selenopyrilium X obtained by precipitation with water, the yield is 72%.

Example 2

Preparation of 2,6-diphenyl-4- (p-methoxyphenyl) selenopyrilium bromine zincate (V)

Perform analogously to example 1 on the basis of 1.79 g (0.005 mol) of 1,5-diphenyl-4- (p-methoxyphenyl) pentanedione-1,5 (II). Obtain 2.51 (71%) of salt V. T _PL = 247-252 ° C. PMR spectrum (CF ₃ COOD / (CD ₃ ) ₂ SO - 1: 1) δ ppm: 8.51 (s, 2H, cat); 3.94 (s, 3H, CH ₃ ); 6.82-8.09 (m, 14H, arom.).

The estimated gross formula of C ₂₄ H ₁₉ SeOZnBr _{3 is} not preserved upon recrystallization and gradually transforms into the form C ₂₄ H ₁₉ SeOBr · 0.5ZnBr ₂ , therefore, the salt was identified through the corresponding perchlorates.

0.71 g (0.001 mol) of Bromzincate V is dissolved in 10 ml of 57% perchloric acid when heated in a boiling water bath. The homogeneous solution is cooled to room temperature, the precipitated crystals are filtered off, washed with dry ether (after adding ether to the mother liquor, a small amount of XI crystals precipitates), and dried. Obtain 0.46 g (91.5%) of 2,6-diphenyl-4- (p-methoxyphenyl) selenopyrilium perchlorate (XI), mp 214-215. Lit. so pl. 213-214 ° C [Kudinova M.A., Krivun S.V., Tolmachev A.I. // HCG. - 1973. - No. 6. - S.857-858]. A sample of mixing with a reliable sample [SU 1816762 B.I. - 1993. - No. 19] depression of the melting temperature is not given.

When using the salt of selenopyrilium obtained by precipitation with water, the yield is 74%.

Example 3

Obtaining 2,6-diphenyl-4-methylselenopyrilium (VI) bromozincate

Perform analogously to example 1 on the basis of 1.33 g of 1,5-diphenyl-3-trimethylpentanedione-1,5 (III). Mp 205-207 ° C. Obtain 2.09 g (68%) of salt VI. _Mp = 205-207 ° C. PMR spectrum (CF ₃ COOD / (CD ₃ ) ₂ SO - 1: 1) δ ppm: 8.65 (s, 2H, cation); 2.65 (s, 3H, CH ₃ ); 7.65-8.05 (m, 10H, arom.).

The estimated gross formula of C ₁₈ H ₁₅ SeZnBr _{3 is} not retained during recrystallization and gradually changes to the form C ₁₈ H ₁₅ SeBr · 0.5ZnBr ₂ , therefore, the salt was identified through the corresponding perchlorates.

0.62 g (0.001 mol) of Bromzincate VI is dissolved in 10 ml of 57% perchloric acid when heated in a boiling water bath. The homogeneous solution is cooled to room temperature, the precipitated crystals are filtered off, washed with dry ether (after adding ether to the mother liquor, a small amount of XI crystals precipitates), and dried. Obtain 0.37 g (91%) of 2,6-diphenyl-4-methylselenopyrilium perchlorate (XII), mp 194.5-196. Lit. mp 195-196 ° C [Kudinova M.A., Krivun S.V., Tolmachev A.I. // HCG. - 1973. - No. 6. - S.857-858]. A sample of mixing with a reliable sample [SU 1703649 B.I. - 1992. - No. 1] depression of the melting temperature is not given.

When using the salt of selenopyrilium obtained by precipitation with water, the yield is 71%.

Claims (1)

A method of obtaining salts of selenopyrilium of formula I

where R = phenyl, R '= phenyl, optionally substituted C ₁ -C ₄ alkoxy, C ₁ -C ₆ alkyl, A ^- = Br ^- .ZnBr ₂ , ClO ₄ ^- , by reacting the corresponding 1,5-diketone with hydrogen selenide obtained by dissolving zinc selenide in the reaction medium, characterized in that the reaction medium is created by mixing an aqueous solution of hydrobromic acid with diethyl ether and acetic bromide, taken in an amount necessary to completely remove water.