Research & Development On (D)-Cysteine Hydrochloride

(D)-Cysteine hydrochloride monohydrate was prepared by the racemic (DL)-cysteine hydrochloride. (DL)-cysteine hydrochloride was neutralised to (DL)-cysteine by ammonia. The produced (DL)-cysteine reacted with acetone bringing (RS)-2, 2-dimethyl-4-thiazolidinecarboxylic acid[(R,S)-DMT], which was combined with (R,R)-Tartaric acid[(R)-TA] and generated (S)-DMT-(R)-TA. After hydrolyzing (S)-DMT-(R)-TA, (R)-TA was eliminated. Finally, (D)-Cysteine rea.cted with hydrochloric acid. The emphasis of the study was put on the process of (S)-DMT-(R.)-TA formation.Starting from the (L)-cysteine hydrochloride, (D)-Cysteine hydrochloride monohydrate was neutralised using sodium carbonate by one-pot means. The difference of process was that (L)-cysteine hydrochloride was prepared by sodium carbonate, instead of ammonia. During this section, the process of asymmetric transformation was paid attention to.The hydrolyzation of (L)-cysteine hydrochloride was studied further. And a new reagent was found, which increased the yield of (D)-Cysteine hydrochloride to 50% and synchronously made the tartaric acid recycle easy. This is our innovation. There has not been reported in civil and abroad by far.The affecting factors of purity, decoloring, crystal form and yield of (D)-Cysteine hydrochloride were considered. When acetic anhydride toke place of part of acetic acid in reaction and when acetone was instead of butanone, the changes were explored.The reactions were done with 25kg and 50kg of (L)-cysteine hydrochloride each twice, the yield of (D)-cysteine hydrochloride was same as small scale. The quality, identified by many factories of pharmacy, is same as Japanese Ajinomoto Co. and reaches EPIV.2, 6-dihydroxy-3-cyanopyridine was synthesized with ethyl formate, ethyl acetate, 2-cyanoacetamide and sodium hydride in toluene. Its structure was identified by IR, MS and ~1H-NMR. The affecting factors of the purifying condition and the yield were examined.