SU427013A1 - METHOD OF OBTAINING 5- - Google Patents

Description

The invention relates to a process for the preparation of thiofbnov-2-aldehyde derivatives, which can be used as physiologically active substances and intermediates in organic synthesis. A known method for the preparation of thiophene-2-aldehyde derivatives by the interaction of a substituted thiophene is general formula where RI is hydrogen, alkyl, halogen, with N-substituted formaldehyde of the general formula HCON where R2 is phen} 1nl, lower alkyl; when heated in the presence of phosphorus oxychloride. A method for the preparation of 5- (4-nitrofeyl) - or 5- (4-methoxy-2-nitrophenyl) thiophene-2-aldehyde is proposed, consisting in the fact that nitroaniline or 4-methoxy-2-nitroaniline is diazotized and the corresponding salt obtained diazon combined with thiofei. m-2-aldehyde in the presence of copper dichloride, followed by separation of the target product in a known manner. L p m i m i r 1. 5- (4-Nitrophenyl) -thiophene-2-aldehyde. 35 g (0.25 mol) of 4-nitroaniline, 63 ml (2.0 mol) of concentrated hydrochloric acid and 90 ml of water are introduced into a 0.5 liter flask. The mixture is heated to completely dissolve the precipitate (80-95 ° C), then it is cooled to -5 ° C and a solution of 18 g (0.26 mol) of sodium nitrite in 40 ml of water is slowly added dropwise. After all the salt solution is added, the reaction mixture is moved at the same temperature for another 1 hour. The resulting solution of the diazonium salt is filtered into a flask immersed in a cooling mixture, and 50 ml of acetone, 37 g (0.3 mol) of tnofeno2-aldehyde and 5 g of copper dichloride are added to it. Then the mixture reacts with an intensive transfer and is brought to room temperature within 2 hours and moved for another 24 hours (2 days to 12 hours). A brown-red solution is formed. At the end of the reaction, acetone is distilled off with steam, and then thiophene-2-aldegnd (–22 g) which does not react. The dark oil remaining in the distillation flask crystallizes after cooling. Double recrystallization from aqueous acetone (1: 2) with coal

m.p. 148-

yellow crystals, 150 ° C are obtained. Yield 11 g (36%).

Found,%: N 6.29; 6.29.

SiNuOZMZ.

Calculated,%: N 6.00.

One detected in the UV spectrum

337 im absorption band with a maximum at (Ige 4.15, in alcohol).

I / K spectrum (EHF tablets), cm: characteristic frequency of the carbonyl group at 16G5, skeletal vibrations of the benzene ring 1593, out-of-plane deformation of the vibrations of two adjacent hydrogen atoms of the benzene core at 860, vibrations of the thiophene cycle at 1225, 1420; the nitro group exhibits two strong absorption bands at 1345 (Vs) and 1510 (Vas).

Phenylhydrazone - red crystals, so pl. 178 ° C (from benzene).

Found,% 13.16; 13.24.

CirHisOa-NaS.

Calculated,%: N 12.99.

2,4 - Dinitrofenilgndrazoy - brown-red crystals, t. Pl. 267 ° C (from benzene).

Found,%: N 16.81; 17.00

CiyHnOeNsS.

Calculated,%: N 16,94.

Oxnm - orange crystals, so pl. 146 ° C (from aqueous alcohol).

Found,%: N 11.20; 11; 58.

CnHgOaNaS.

Calculated,%: N 11.29.

Example 2. 5- (4-Methoxy-2-nitrophenyl) tpopheno-2-aldehyde.

In a three-liter flask with a capacity of 1 l, equipped with a mechanical stirrer, an addition funnel and a thermometer, 42 g (0.25 mol) of 4-methoxy-2-nitroaniline, 63 ml (2.0 mol) of concentrated hydrochloric acid and 75 ml of water are introduced . The mixture is heated (95-100 ° C) until a homogeneous solution is obtained, then cooled with ice-salt to О-5 ° C (this results in a yellow precipitate of aniline hydrochloride salt), is diazotized in Example 1 and the mixture is moved at O-5 ° C another 1 hour

50 ml of acetone, 41 g (0.37 mol) of thiophene-2-aldehyde, 5 g of copper dichloride are added to the obtained solution of the diazonium salt, and the mixture is transferred for 24 hours at room temperature. After this time

the resulting brown-red solution is distilled with steam. After distilling off the acetone and the thiophene-2-aldehyde which had entered into the reaction (-26 g), the dark oil remaining in the flask and cooled (0 ° C) crystallized. Recrystallization from aqueous alcohol (1: 2) gives yellow needles, so pl. .. Yield 9 g (31%). Found,%: N 5.31.

CisHgO NS.

Calculated,%: N 5.31.

In the UV spectra, two absorption bands were detected with max. At 263 nm (Ige 3.98) and 305 nm (Ige 4.06).

IR spectrometer (KBr tablets), characteristic frequency of the carbonyl group at 1665, out-of-plane deformation vibrations of two adjacent hydrogen atoms of the benzene core at 820, common-mode and antiphase vibrations of the thiophene cycle at 1230, 1360 and 1440-1455, symmetric and asymmetrical vibrations of the nitro group, respectively, nri 1 : 360 and 1525-1540.

4-Nitrophenylhid | razon-crystals of brick color, t. Pl. 197 ° C (from benzene).

Found,%: N 14.29.

C, 8H, 405N4S.

Calculated,%: N 14.07.

2,4-Dinitrophenylhydrazone - light brown crystals, so pl. 235 ° C (from benzene).

Found,%: N 15.48.

C.gHjaOyNsS.

Calculated,%: N 15.79.

Oxnm - orange crystals, so pl. 145 ° C (from aqueous alcohol).

Found,%: N 10.27.

C 2H o04N2S.

Calculated,%: N 10.00.

| ADDITIONS AND RESULTS

The method obtained with 5- (4-nitrophepyl) - or 5- (4-methoxy-2-ntrophenyl) - thiophene-2-aldehyde, characterized in that nitroaniline or 4-methoxy-2-nitroapilip is diazotized and the resulting corresponding diazopy salt is combined with thiophene- 2-a.dehyde in the presence of dichloride copper, followed by separation of the target product in a known manner.