Abstract: A synthesis method of alanyl-glutamine includes the steps of: The N-terminal protected alanine reacts with triphenylphosphine and hexachloroethane in organic solvent to form active ester, the active ester reacts with glutamine in a solution mixture containing organic solvent and aqueous solution of inorganic base, the resultant mixture is acidified with inorganic acid, and then the N-terminal protecting group is removed. In this method, the raw materials are cheap, the synthesis technique is simple, no disposals of separation and purification are needed, the product is easy to be separated and purified, the toxicities of all the reagents used in the course of production are minimal, it is advantageous to environment protection.

Abstract: Heterocyclic compounds represented by the general formula (I) and having elastase inhibiting activity; and intermediates for the synthesis thereof: (I) wherein R1 is a heterocyclic group represented by the general formula (II): (II) [wherein A represents the presence or absence of a benzene ring; X is oxygen, sulfur or NH; and Y is nitrogen or CH], and the heterocyclic group may be substituted with one to three substituents which may be the same or different and are selected from the group consisting of lower alkyl, lower alkoxy, and phenyl which may be substituted with optionally halogenated lower alkyl, lower alkoxy or halogeno; and R2 and R3 are each hydrogen or hydroxyl, or R2 and R3 may be united to form an oxo group, with the proviso that both are not hydrogen.