Reaction of 2‐acyl‐6‐methylbenzo[b]furan‐3‐acetic acids derivatives with hydrazine

Abstract

Reaction of 2-acyl-6-methylbenzo [b]furan-3-acetic acids and their derivatives such as amides and esters with hydrazine does not give expected 1-alkyl-5H-benzofuro[2,3-e]diazepin-4-ones ones but results in 2-amino-7-methyl-2H-benzo [4,5]furo [2,3-c]pyridin-3-ones or (3-R-6-methylbenzo[b]furan-2-yl)alkyl ketone azines.

Condensed diazepines. synthesis of 1-aryl-3,5-dihydro-4H-1-benzofuro-[2,3-d][1,2]diazepin-4-ones

“…Similar conversions have not been described in the 1-benzofuran series. As was shown in our preliminary publication [10], heterocyclization of hydrazones of (2-acyl-1-benzofuran-3-yl)acetic acid leads to the corresponding azine, but heterocyclization of hydrazones of arylamides of (2-acetyl-1-benzofuran-3-yl)acetic acid, depending on the conditions, takes place with the formation of 2-amino-1-methyl-1-benzofuro [2,3-c]pyridin-3-one or azines of arylamides of (2-acetyl-1-benzofuran-3-yl)acetic acid.…”

Heterocyclization of 2-acyl-3-indolylacetic acids using hydrazine. Synthesis of 2,3-dihydro-2-oxo-5-R1-1H-[1,2]diazepino[4,5-b]indoles

“…We have recently shown that the reaction of 2-acetylbenzo[b]furan-3-acetic acid as well as its ester and amide derivatives with hydrazine hydrate leads not to the corresponding benzofurodiazepines but rather to 2-aminobenzofuro[2,3-c]pyridin-3(2H)-ones or azines of 2-acetylbenzo[b]furan-3-acetic acid [14].…”