RU2344130C2 - 2-phenyl-1,2,3-triazole production method - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: new production method of 2-phenyl-1,2,3-triazole using glyoxal phenylosazone ring formation with new triflate copper catalyst Cu(OSO₂CF₃)₂, both without solvent in melt at 130°C and in high-boiling solvent mediums (toluene, o-xylene, butanol) at boiling temperatures. End product is extracted with high yield column chromatography.

EFFECT: development of new production method of 2-phenyl-1,2,3-triazole.

3 cl, 5 ex

Description

The invention relates to the field of high-energy compounds, in particular to a method for producing 2-phenyl-1,2,3-triazole, which is a promising precursor for the synthesis of energetically active materials, namely 4-nitro-1,2,3-triazole.

Known methods for producing 2-phenyl-1,2,3-triazole by dry distillation of phenylozazone glyoxal [HVPechmann. Annalen der Chemie. 1891. B.262. S.265-277] (yield 20%); when heated to 75-100 ° C phenylozazone glyoxal with an aqueous solution of copper sulfate (CuSO ₄ ) for 6.5 h, followed by isolation of the product by steam distillation and appropriate treatment [JLRiebsomer. J. Org. Chem. 1948. V.13. No. 6. P.815-821; El-Khadem H., El-Shafei ZMJ Chem. Soc. 1958. No. 9. P.3117-3119] (yield 59, 50%, respectively); when heated to 180-210 ° C phenylozazone glyoxal with a catalytic amount of copper monochloride (CuCl) [Yu.A. Naumov. In the book. Methods for producing chemical reagents and preparations. M .: Chemistry. 1969. Issue 18. S.196-198] (yield 66.6%). The disadvantages of the above methods for producing 2-phenyl-1,2,3-triazole are low yield, high reaction temperatures, and the use of water vapor (in the case of low reaction temperatures).

Closest to the claimed invention (prototype) is a method for the synthesis of 2-phenyl-1,2,3-triazole by cyclization of the phenylazone glyoxal under the influence of a CuCl catalyst in the presence of anhydrous CaCl ₂ in the melt at 170-190 ° C, the whole process includes 9 stages: 1) - synthesis, i.e. cyclization of glyoxal phenylozazone followed by distillation of the product from the reaction mixture, while 2-phenyl-1,2,3-triazole is distilled off together with aniline in the range: 170 ° C / 45-50 mm Hg - 190 ° C / 10 mm RT. st .; 2) - treatment of the distilled mixture with water, stirring and acidification with 20% sulfuric acid; 3) - separation of the organic layer (the first fraction of 2-phenyl-1,2,3-triazole) on a separatory funnel; 4) - saturation of the resulting aqueous solution with sodium chloride; 5) - extraction of 2-phenyl-1,2,3-triazole with ether (2 times) and combining it with the first fraction; 6) - drying the combined extract with anhydrous sodium sulfate; 7) - separation of the solution of 2-phenyl-1,2,3-triazole from the desiccant (filtration); 8) - removal of solvent (ether); 9) - the selection of the target product (2-phenyl-1,2,3-triazole) by distillation in vacuum [L.I. Vereshchagin, V.M. Nikitin, V.I. Meshcheryakov, G.A. Gareev, L.P. .Kirillova, V.M.Shulgin. ZhORKH. 1989.Vol. 25. Issue 8. S.1744-1747] (75% yield).

The disadvantage of the above prototype are: the complexity (multi-stage) of the process of isolating the target product, as well as the high temperature of receipt.

The purpose of our invention is to simplify the method of producing 2-phenyl-1,2,3-triazole.

The goal is achieved:

1) using a fundamentally new catalyst - copper triflate Cu (OSO ₂ СР ₃ ) ₂ for cyclization of glyoxal phenylazone, which, as in the prototype, is the initial reagent for this synthesis; the use of a new catalyst allows to reduce the process temperature to 130 ° C, if the process is conducted without solvent;

2) the use of high-boiling solvents (toluene, o-xylene, butanol) at their boiling points (110-145 ° С), which also allows to reduce the process temperature, and it should be noted that before that, in none of the known methods, solvents were used;

3) using the column chromatography method for the isolation of 2-phenyl-1,2,3-triazole (silica gel, LSL grade ₂₅₄ 5/40 µ, eluent: hexane: sulfuric ether mixture in a ratio of 1: 2), which greatly simplifies the isolation process, allowing reduce the total number of process steps to three in the case of fusion without solvents and to four when the process is conducted in a solvent environment (see examples).

It should be noted that 2-phenyl-1,2,3-triazole obtained by the proposed method is characterized by a high degree of purity: 99.96-100%, according to the data of chromatography-mass spectrometry. The scheme of the synthesis of 2-phenyl-1,2,3-triazole can be represented as follows:

The following non-limiting examples illustrate the invention.

Mixed phenylozazone glyoxal cyclization

Example 1. Isolation of 2-phenyl-1,2,3-triazole without column chromatography. A well-mixed mixture of glyoxal phenylazone 1 g (4.2 mmol) and copper triflate Cu (OSO ₂ CP ₃ ) ₂ 0.05 g (0.14 mmol) was placed in a Wurz flask. The reaction mixture was heated under argon to 130 ° C (until the glyoxal ozone was completely melted), followed by distillation of the distillate (2-phenyl-1,2,3-triazole-aniline) at 130 ° C / 90 mm Hg. - 105 ° C / 17 mm Hg The total process time is 50 minutes, which includes the melting time of the initial glyoxal phenylozazone, the cyclization process itself and distillate distillation. Next, the process of isolation of the target product was carried out: sulfuric ether was added to the obtained distillate; the ethereal solution was treated with 10% hydrochloric acid in a separatory funnel to remove aniline, washed with distilled water until the chlorine ion was negative, dried over calcined potassium carbonate. After ether was distilled off, the substance was distilled in vacuo. Received 0.5 g (82.0%, higher yield than that of the prototype) 2-phenyl-1,2,3-triazole, a colorless liquid, so Kip. 96 ° C / 10 mmHg, n _d ²⁰ = 1.5880. R _f = 0.84. The reaction progress was monitored by thin-layer chromatography using Silufol plates with an attached layer, eluent: hexane-sulfur ether (1: 2), and chromatography-mass spectrometry. (Mass spectra were obtained on a GCMS-QP5050A chromato-mass spectrometer from Shimadzu). Found,%: C 66.23, H 5.09, N 28.55. Calculated for C ₈ H ₇ N ₃ ,%: C 66.21, H 4.82, N 28.97. The purity of the product is 99.96% (according to chromatography-mass spectrometry). All characteristic bands are present in the IR spectrum (ν, cm ^-1 ) of 2-phenyl-1,2,3-triazole: stretching vibrations of С-Н bonds of the triazole ring at 3139 sp. and 3124 words, benzene ring at 3080 words, 3059 words, 3036 words, C = C of aromatic ring at 1599 seconds, 1502 r.s., 1476 words, non-planar deformation vibrations of monosubstituted benzene ring at 755 and 694, valence vibrations of the triazole ring at 1410 s, 1376 s, deformation vibrations of С-С and С-Н bonds of the triazole cycle at 1260 s, 1103 s, 1086 sr, 1022 sr, 961 s, 951 s ., 912 sr., 822 s., 669 s. (IR spectra were recorded on a Bruker IFS-25 spectrometer in a microlayer). ¹ H NMR (δ, ppm): 8.03, 7.55, 7.41 (resonant signals of protons of the phenyl fragment), 8.11 (resonant signal of protons of the triazole fragment at position 4,5 of 2-phenyl-1,2,3-triazole is manifested) . ¹³ C NMR (δ, ppm): 139.31 (ipso), 129.73 (meta), 127.75 (pair) and 118.50 (ortho) (resonance signals of carbon atoms of the phenyl ring); 136.47 (resonance signal of C-4,5 triazole fragment). ( ¹ H and ¹³ C NMR spectra were recorded on a Bruker instrument, model DPX 400 (400 MHz) in DMSO-d ₆ ).

Example 2. Isolation of 2-phenyl-1,2,3-triazole using column chromatography.

A triturated and well-mixed mixture of 2 g (8.4 mmol) of phenylazone glyoxal and copper triflate Cu (OSO ₂ СР ₃ ) ₂ 0.1 g (0.28 mmol) was placed in a Wurz flask. The synthesis of 2-phenyl-1,2,3-triazole was carried out analogously to example 1 to isolate the distillate. And then the separation of 2-phenyl-1,2,3-triazole from aniline was carried out on a column 46 cm high, 2 cm in diameter, filled with silica gel (LSL grade ₂₅₄ 5/40 µ) - the ratio of the purified mixture of substances to the sorbent is 1:50. Eluent: hexane-sulfur ether (1: 2). With this extraction method, the number of process steps is reduced to three compared to the prototype: 1) synthesis: cyclization of glyoxal phenylazone; 2) - filtering from solid particles of the catalyst; 3) - isolation of 2-phenyl-1,2,3-triazole by column chromatography. Received 0.98 g (80.7%, higher yield than in the prototype) 2-phenyl-1,2,3-triazole, t. Kip. 96 ° C / 10 mmHg, n _d ²⁰ = 1.5880. The purity of the product is 100%.

Cyclization of glyoxal phenylozazone in solvents

Example 3. In a three-necked flask equipped with a stirrer, a refrigerator, an argon inlet tube, a well-mixed mixture of phenylozazone glyoxal 1 g (4.2 mmol) and copper triflate Cu (OSO ₂ CF ₃ ) ₂ 0.05 g (0.14 mmol) and 10 ml of toluene was placed. The reaction mixture was boiled at 110 ° C. The reaction time was 7 hours. The progress of the reaction was monitored by thin layer chromatography using plates with a fixed Silufol layer, eluent: hexane-sulfur ether (1: 2), and chromatography-mass spectrometry. After cyclization was completed, toluene was distilled off on a water-jet pump. Isolation of 2-phenyl-1,2,3-triazole was carried out on a column filled with silica gel (LSL grade ₂₅₄ 5/40 µ), eluent: sulfuric ether-hexane (2: 1). The process proceeds in four stages: 1) - synthesis: cyclization of glyoxal phenylazazone; 2) - filtering from solid particles of the catalyst; 3) - distillation of the solvent; 4) - isolation of 2-phenyl-1,2,3-triazole by column chromatography. Received 0.55 g (90.2%) of 2-phenyl-1,2,3-triazole, so bp. 94 ° C / 8 mmHg, n _d ²⁰ = 1.5880. The purity of the product is 100% according to chromatography-mass spectrometry.

Example 4. Under conditions similar to those described in example 3, a well-mixed mixture of phenylazone glyoxal 2 g (8.4 mmol) and copper triflate Cu (OSO ₂ CF ₃ ) ₂ 0.1 g (0.28 mmol) and 20 ml of o-xylene was placed. The reaction mixture was boiled at 145 ° C. The reaction time was 6.5 hours. The progress of the reaction was monitored by thin-layer chromatography using plates with a fixed Silufol layer, eluent: hexane-sulfur ether (1: 2), and chromatography-mass spectrometry. After cyclization was complete, the catalyst was filtered off from the reaction mixture, o-xylene was distilled off by rotade test. The isolation of 2-phenyl-1,2,3-triazole was carried out analogously to example 3. Received 0.98 g (74.0%) of 2-phenyl-1,2,3-triazole, so Kip. 96 ° C / 10 mmHg, n _d ²⁰ = 1.5880. Product purity 99.98% according to chromatography-mass spectrometry.

Example 5. Under conditions similar to those described in example 3, a well-mixed mixture of glyoxal phenylazone 1 g (4.2 mmol) and copper triflate Cu (OSO ₂ CF ₃ ) ₂ 0.05 g (0.14 mmol) and 10 ml of n-butanol was placed. The reaction mixture was boiled at 117 ° C. The reaction time is 7.5 hours. After cyclization, the catalyst was filtered off from the reaction mass, butanol was distilled off by rotade test. The isolation of 2-phenyl-1,2,3-triazole was carried out analogously to example 3. Yield 0.47 g (68.0%) of 2-phenyl-1,2,3-triazole, b.p. 94 ° C / 8 mmHg, n _d ²⁰ = 1.5880. Product purity 99.98% according to chromatography-mass spectrometry.

Claims (3)

1. The method of obtaining 2-phenyl-1,2,3-triazole by cyclization of phenylozazone glyoxal when heated in the presence of a copper salt as a catalyst, followed by isolation of the target product, characterized in that copper triflate is used as a copper salt and the process is carried out as without solvent at 130 ° C for 50 min, and in a medium of high boiling solvents at boiling points for 6.5-7.5 h, and column chromatography is used to isolate 2-phenyl-1,2,3-triazole . 2. The method according to claim 1, characterized in that toluene, o-xylene, butanol are used as high boiling solvents. 3. The method according to claim 1, characterized in that for column chromatography, silica gel of the LSL grade ₂₅₄ 5/40 µ is used as the stationary phase, and a mixture of hexane: sulfuric ether in a ratio of 1: 2 is used as eluent.