Acylhydrazones azomethines

C=N bonds in acylhydrazone groups, which are formed by the condensation of hydrazides with carbonyl groups, exhibit reversibility under mild conditions. Like polyimines, polymers with acylhydrazone functionalities exhibit dynamic aspects through the reversibihty of the azomethine bond. Skene and Lehn have reported the synthesis of polyacylhydrazones and their dynamic features (Scheme 8.3) [23]. High molecular weight polyacylhydrazone 13 was prepared by the condensation of the corresponding dihydrazide and dialdehyde in the presence of an acid catalyst. When 13 was treated with aryl dialdehyde 14 or aryl dihydrazide 15 in... 

N2OC2 Acylamidines Acylamidinium chlorides Acylcyanamides Acylhydrazones N-Acylnitrilimines a,a-Alkoxyaminonitriles 1 -Alkoxycyanamides Aminomethoximes Azomethine imides Azine monoxides Carbamyl cyanides N -Cyaniminoesters Cyanoformamides... 

Asymmetric inverse-electron-demand 1,3-dipolar cycloaddition of C,A-cyclic azomethine imines with c-rich dipolarophiles was accomplished with a high stereo-selectivity by using an axially chiral dicarboxylic catalyst (40)." The metal-free silicon Lewis-acid-catalysed 3-1-2-cycloadditions of A-acylhydrazones with cyclopentadiene provides a mild access to pyrazolidine derivatives in excellent... 

Acylhydrazones from azomethines. 5-Hydroxymethylfurfurylideneanilide added rapidly to a hot soln. of isonicotinyl hydrazide, and heated briefly to boiling -> 5-hydroxymethylfurfurylideneisonicotinyl hydrazide. Y 97%. F. e. and reactions s. F. Knotz, M. 89, 718 (1958). 

Related to azomethine imines, the acylhydrazone 58-olefin 59 cycloaddition also yields pyrazolidines 60 (Scheme 41.13). ... 

---