摘要:
A one-pot process for the preparation of .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride is disclosed (.alpha.-APM(HCl)). .alpha.-APM(HCl) is an intermediate in the preparation of aspartame.
摘要:
A one-pot process for the preparation of .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride is disclosed (.alpha.-APM(HCl)). .alpha.-APM(HCl) is an intermediate in the preparation of aspartame.
摘要:
N-formyl-L-aspartic anhydride is prepared using a minimum excess of formic acid. Acetic anhydride and a C.sub.3 -C.sub.6 secondary alcohol are added to the reaction mixture to consume excess formic acid. The reaction is suitable for further reactions without modification.
摘要:
A new process for the preparation of 17.beta.-hydroxy-3-oxo-17.alpha.-pregn-4-ene-21-carboxylic acid .gamma.-lactone is described herein. The process makes use of androst-4-ene-3,17-dione as the starting material and 17.alpha.-ethynyl-17.beta.-hydroxyandrost-4-en-3-one as an early intermediate.
摘要:
A process for the isomerization of maleic acid, its monoesters and monoamides in the presence of thiourea in anhydrous conditions at elevated temperature to the corresponding fumaryl forms yields intermediates which are useful in the synthetic pathways of aspartame and other useful polypeptides.
摘要:
A process for preparing 17-hydroxy-3-oxo-17.alpha.-pregna-4,6-diene-21-carboxylic acid .gamma.-lactone by contacting 17-hydroxy-3-oxy-17.alpha.-pregna-3,5-diene-21-carboxylic acid .gamma.-lactone with an appropriate halogenating agent in the presence of an amine base, the corresponding hydrohalide salt thereof, and approximately 1-2 molar equivalents (relative to the lactonic starting material) of water, using a cold solvent as the contact medium, and heating the resultant mixture with a dehydrohalogenating agent, is disclosed.
摘要:
The present invention is concerned with an improved process for the preparation of trimethylsulfoxonium bromide. The improvement in the process comprises the addition of a scavenger to the reaction mixture of dimethyl sulfoxide and methyl bromide.
摘要:
A new process utilizing certain novel intermediates for the preparation of 17.beta.-hydroxy-3-oxo-17.alpha.-pregn-4-ene-21-carboxylic acid .gamma.-lactone is described herein. The procedure utilizes readily available and inexpensive sarsasaponin as starting material.