Reactions of 2-arylhydrazonoacetamidoximes with orthoesters

Abstract

The reactions of 2 arylhydrazono 2 carbamoylacetamidoximes with orthoesters afford either 3 arylhydrazono 1,2,4 oxadiazoles or 1,2,3 triazoles, depending on the reactant structure.

Orthoesters: Multiple Role Players in Organic Synthesis

“…The intermediate, namely 1‐(alkane carbonyl)‐2‐ethoxymethylen hydrazine 115 , plays a key role in all of these reactions. Reaction of hydrazone encompassing the amidoxime group, together with orthoester is another strategy for producing triazole and 1,2,4‐oxadiazole . The reactions of arylhydrazono amidoximes with TEOF s in the presence of catalytic amount of BF 3 .OEt 2 produced triazoles and oxadiazoles, which were separated by fractional crystallization using EtOH (Scheme ).…”

Synthesis and antiproliferative efficiency of novel bis(imidazol-1-yl)vinyl-1,2,4-oxadiazoles

“…The O-acylation of amidoxime by an activated carboxylic acid is followed by cyclodehydration in two steps. 9 Activated carboxylic acid derivatives used for the o-acylation step include esters, 10,11 acid chlorides, 12 and anhydrides. 13 The use of carbodiimides such as EDC 9 and DCC 10 for the in situ activation of carboxylic acids was reported.…”