METHODS OF PRODUCING ENAMINES Russian patent published in 2016 - IPC C07D295/84 C07C209/52 C07C323/27 

FIELD: chemistry.

SUBSTANCE: invention is related to an improved method of producing enamines, preferably 1-(3-methylsulphanyl-but-1-enil) pyrrolidine. Enamine can be used for various reactions, including reduction to produce amines. Method of producing enamines is performed by the following scheme . Method involves (A) bringing the first mixture with the second mixture in a reaction zone. Note here that (1) the above first mixture contains carbonyl (i.e. aldehyde or ketone), with the following formula (a), where one of R1 and R2 is a C₁-C₆alkyl, and the other is a S-R6, where each R6 is a C₁-C₆alkyl, and (b) where R3 is H, and (2) where the said second mixture contains non-polar solvent with high boiling point and amine, with the following formula , where R4 and R5, taken together with N, are 5-or 6-member saturated or unsaturated ring. Method also involves (B) reaction in said reaction zone of said amine and the said carbonyl to form enamine and H₂O, in conditions of azeotropic distillation, with (1) pressure from 100 Pa (PA) to 120,000 PA, and (2) temperature lower than thermal decomposition of the said enamine during the said reaction; (C) removal of gaseous phase including the above non-polar solvent with high boiling point, amine, and H₂O; (D) condensation of said gas phase from step (C) with formation of condensate; and (E) contacting said condensate from step (D) with restoring mixture containing H₂O and the means to remove an amine to obtain separate mixture containing said amine. Optionally performing steps (F) for an optional removal of the said amine from step (e) back into the said reaction zone. Mainly at step a) equimolar amounts of the said amine and the said carbonyl are used. Molar ratio of amine to carbonyl can range from 0.9 to 1.2. Said non-polar solvent with high boiling point is an aromatic hydrocarbon solvent, for example, benzene, toluene, xylene. Azeotropic distillation is carried out at the temperature from 10 °C to 80 °C and the pressure from 1,000 PA to 60,000 PA.

EFFECT: method allows significantly reducing consumption of initial amine (approximately in 2 times) while maintaining high output of the obtained product.

14 cl, 2 ex