SU732259A1 - Method of preparing 2-aryl-(alkyl)-benzenes - Google Patents

Description

 the ratio of initial reagents

, lsl-l l, 2.

dimethylformamide, dimethylacetamide, N-methylpyrrolidone, hexamethyltriamide of phosphoric acid in the amount of 50-100 ml per 0.1 mol of the starting chloride, change in the ratio of the starting products (from 1: 1 to 1; 2 and 2; 1) does not lead to quality improvement. Reducing the amount of solvent is impractical because of the increased reaction time due to heterogeneity and lower product quality, increasing solvent consumption leads to lower yields. At temperatures below 120 ° C, the reaction slows down dramatically, the upper limit is limited by the boiling points of solvents and the possibility of side reactions. Without cooling the reaction mass after the reaction, the yield of the final product decreases, the lower limit of the cooling is limited by the freezing point of the solvent and the relatively low dependence of the solubility of the final products on the temperature at a temperature below.

The proposed method allows to obtain pure products directly from the reaction mixture with a high melting point, while in the known methods, similar or lower melting points of the target compounds are obtained only after additional purification.

In table 1 and in the examples are some products obtained by the proposed method. Table 2 presents comparative data on the purity of the products according to the proposed method directly from the reaction mixture and similar products obtained by known methods, followed by purification, for example, recrystallization

From Table 2 it can be concluded that the compounds obtained by the proposed method are not only not inferior in purity, but also superior to similar compounds obtained by known methods.

Example 1. Preparation of 6-nitro2- (p-nitrophenyl) benzoxazole. Upon cooling, dissolve 20 g (0.122 mol) of 2-amino, 5-nitrophenap in 100 ml of dimethylacetamide. In the resulting solution load 25 g (0,135 mol) of p-nitrobenzoyl chloride. The cooling is removed, the reaction mass is heated to boiling. The resulting solution is boiled for 5 hours.

(Precipitated upon cooling, the precipitate is filtered off, washed with water and dried.

Receive 20.9 g (60%) of 6-nitro, g of 2- (p-nitrophenyl) benzoxazole, so pl. 214-215C.

Found,%: N 14.9. С о H-jNjOj

Calculated% N 14.7.,

 2. Preparation of 2, 4-phenylene (bis) -5-nitrobenzoxazole. 20 g (0.122 mol) of 2-hilino, 4-nitrophenol are dissolved in 100 ml of dimethylformamide and V is charged with stirring. 13.7 g (0.068 mol) of terephthaloyl chloride, 5 The reaction mass is heated to boiling for 6 hours. The precipitate formed on cooling is filtered off, washed with water and dried.

This gives 21.5 g (76%) of 2, 40-phenylene (bis) -5-nitrobenzoxazole1, m.p. 370-372 °.

Found,%: N 13.9.

20 iD 4 ° 6Calculated,%: N 14.0.

Example 3. Getting 2- (t-nitrophenyl) -benzimidazole. 10.8 g (0.1 mol) -phenylenediamine is dissolved in 50 mp of dimethyl acetamide;

changing and cooling to

18.6 g (0.1 mol) of t-nitrobenzoyl chloride are added, after which the reaction mass is heated at 120 ° C for 8 hours, cooled before and filtered. The precipitate is washed with water, dried.

16.3 g (78%) of 2- (t-nitrophenyl) benzimidazole are obtained, m.p. 204-206 Found: N 14.4. , N, 0 ,, Calculated,%: N 17.0.

Example4. Preparation of 5-liter-2- (p-nitrophenyl) benzimidazole. 15.3 g (0.1 mol) of 4-nitro-o-phenylenediamine is dissolved in 50 ml of phosphoric acid hexamethyltriamide, 18.6 g (0.1 mol) of p-nitrobenzoyl chloride are added with cooling, and the reaction mass is heated to boiling (232 ° C) for 1 h, cooled, the precipitated precipitate is filtered off, washed with solvent and water,

dried

Receive 22.5 g (80%) of 5-nitro, 2- (p-nitrophenyl) benzimidazole, so pl. 360-362.

Found,%: N 19.7. C, HgNjO .. Calculated,%: N 19.8.

(Table

370-372

358-360

Noros

soon

445-450

452-455

360-362

357-358

245-247

204-206

303-305

Claims (2)

274-276. Claim 1; The method of obtaining 2-aryl (albenzazoles of the formula where X is KH, 0.5, R R .., is H, NM, j., COOI;, CCH2, PN- (0, based on o-phenylenediamines, o-a phenols or o-aminothiophenols. by heating the polar solvent by heating to release the desired product, characterized in that, in order to simplify the process technology, improve product quality and expand the range, 2-aryl (alkyl) benazoles, o-phenylenediamine, o- aminophenols or o-aminothiophenols are reacted with carboxylic acid chlorides, the amide solvent is used as the polar solvent blender, the process is carried out at 120-230 ° C and the separation is carried out while cooling the reaction mass to 0-20 C. 2. The non .l method, characterized in that the starting reagents are used at a ratio of 1: 1-1: 1.2. information taken into account in the examination of 1 Phillips, MA, I. Chem, Soc., 1928, 2395, 2. Hein D.W. I.Am, Chew. Soc. 1957, f79, 427-429,