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2005-05-16) * 3 of a scientific presentation acetyl thio-2-methyl propionyl-L-proline Improved preparation of Chen Jie (Xinjiang Aksu Nongyi Shi Hospital,[link widoczny dla zalogowanych], Xinjiang Aksu 843000) Abstract: The purpose of shortening A sulfur-based 3-2-methyl-acetyl propionyl-L-proline production cycle, reduce production costs, improve yield and quality. Methods Na2CO as a catalyst in the L-proline dropping chloride solution, filtered,[link widoczny dla zalogowanych], and, cooling, obtained from 3 acetyl-thio-2-methyl propionyl-L-proline. Results acyl oxygen meter, more than 38% yield, mp82-84 ℃, the purity of 99.85% (HPLC method). Conclusion The method is simple, high yield, low cost, suitable for industrial production. Keywords: 3 to acetyl-thio-2-methyl propionyl-L-proline; Preparation Key words: R914.5 Document code: A Article ID :1004-2407 (2006) 02-0056-- A sulfur-based 013-2-methyl-acetyl propionyl-L-proline [referred to as free acid (1)], is the preparation of ACE inhibitor,[link widoczny dla zalogowanych], captopril (Captopril) intermediates, the preparation method,[link widoczny dla zalogowanych], the original process for L-proline solution, while dropping NaOH solution and chloride (3 to acetyl-thio-2-methyl propionyl chloride). Required to maintain the reaction pH value of 8 to 9, due to severe reactions and must be ready to test pH value, the operation is difficult. If too alkaline,[link widoczny dla zalogowanych], the generation of free salt easily hydrolyzed to produce low molecular acids, resulting in the final product sticky and difficult to form crystals; if pH <7, then the dropping of the chloride decompose, resulting in waste and substandard quality of products . In order to obtain products of acceptable quality, dropping finished washing need to add ethyl acetate and other organic small molecule impurities. And the need to wash the mother liquor after the steam addition to ethyl acetate, then add active carbon, the operation is very complex and long production cycle, product quality and difficult to control. View from the reaction conditions, the control solution pH value is very crucial, I use NaCO, and as the base. One directly into the reaction solution, it formed during the reaction N% CO and NaHCO, buffer solution, to pH 8 ~ 9, maintained, reducing the operation more difficult, shorten the production cycle. The average yield of products increased from 32% to 38% to 40%. 1.1 1 instrument and reagent reaction flask four instruments (500mL); balance; thermometer; separating funnel (100mL); balance dropping funnel (100mE); funnel; mixer; optic analytical balance; high pressure liquid chromatography . 1.2 reagent L-proline; Na2CO,; 3 a acetyl thio-2-methyl propionyl chloride (the chloride); ethyl acetate; hydrochloride (6tool · L); NaCl, more reagents were chemically pure . 2 Methods and Results 2.1 free acid (1) Preparation of four-neck flask 500mL water 300mL, stirring L-proline 36.5g. Cooled with ice bath to 0 ~ a 2 ℃, adding Na: CO73g. Dropwise 5g chloride (content 95%), maintaining 0 eleven 3 ~ C, dropping finished, the reaction after 1h. Filter cake with cool distilled water (0 ~ C or so) washing 2 times, each time 15mL. Mother liquor and wash liquid detergent merger is completed, heated to 30 ℃, dropping hydrochloric acid (6mol · L) of about 50mL, to pH1-2, appears crystal, a temperature of 20-25 ~ C, reaction of 1h, cooled to ice bath 0 eleven 2 ~ C, 2h, filtered, washed with water 2 times, each time 25mL, filtration, drying derived. 2.2 The results yield 3g (the chloride meter), yield 38.56%. mp82-84 ℃, the purity of 99.85% (HPLC method). 3 to discuss the reaction pH relatively constant, can reduce the incidence of side effects, so that impurities reduce, not by ethyl acetate washing, distillation, de-carbon and other steps to reduce costs, reduced production cycle by the original 38h 14h, increased product yield rate and quality, reduce the operation difficulty, so that the products a pass rate of 100%, removing extracted with ethyl acetate, washing, recycling and other steps to avoid contamination of organic matter, reducing the environmental costs. Shorten the process, improved product yields. In the case does not increase investment, production can be expanded to 2.5 times the original.
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