Synthesis of some new chiral tricyclic and macrocyclic pyridine derivatives as antimicrobial agents

Abstract

A series of chiral macrocyclic pyridines has been prepared starting from N2,N2-(pyridine-2,6-dicarbonyl)diamino acid hydrazides (2a-c) and N,N-bis-(1-carboxy-2-substituted)-2,6-diaminocarbonyl)pyridines (3a,b). The coupling of (2a-c) with 2,6-pyridine dicarbonyldichloride (4) gave the compounds (5a-c). Compounds 2a-c were coupled with 2,6-diacetylpyridine (6) to yield compounds (7a-c) and with heterocyclic aldehydes (8) or (10) to give the compounds (9a-c) or (11a-c). In addition, the hydrazides (2a-c) were reacted with diformylcalix[4]arene 12 to afford the macrocyclic calix[4]arene hydrazone derivatives (13a-c) in reasonable yields. Finally, reaction of diaminocalix-[4]arene derivatives (14a,b) with hydrazides 2a,b or acids (3a,b), using azide or mixed anhydride methods afforded macrocyclic calix[4]arene derivatives 15a,b and 16a,b, respectively. The structure assignments of the new compounds are based on chemical and spectroscopic evidence. The biological activity screening tests showed that many of the obtained compounds exhibit high antimicrobial activity comparable to ampicillin and chloramphenicol which are used as reference compounds.