A Convenient Synthesis of New Pentaazacyclopentanaphthalene and Pentaazaphenanthrene Derivates

Abstract

Reaction of N-{3-cyano-6-[4(5-oxo-2-phenylhydrazono-4,5-dihydroimidazol-1-yl)phenyl]-4-phenylpyridin- 2-yl}formimidic ethyl ester (3) and 3-[4-(3-amino-4-imino-5-phenyl-3,4-dihydropyrido[ 2,3-d]pyrimidin-7-yl)phenyl]-2-phenyl-5-phenylhydrazono-3,5-dihydroimidazol-4-one (4) with different reagents has been investigated and discussed. Some of the obtained compounds were tested for their antimicrobial activity.

Synthesis of bioactive polyheterocyclic ring systems as 5α-reductase inhibitors

“…In conclusion, simple synthetic strategies for the synthesis of tri and tetra heterocyclic ring systems namely [1,2,4]triazolo [4,3-a] pyrido [4,3-d] pyrimidines 8 and [1,2,4]triazolo[4 0 ,3 0 :1,2]pyrimido [4,5-b] [1,6]naphthyridine-5-one 15 were described. The structures of compounds 8 and 15 were confirmed by spectroscopic and X-ray crystallographic analyses.…”

“…Reaction of 3 with the appropriate hydrazonoyl chlorides 5 in dioxane in the presence of triethylamine under reflux was found to give in each case one isolable product (TLC) that was identified to be [1,2,4]triazolo [4,3-a]pyrido [4,3-d]pyrimidines 8 rather than its isomeric structure [1,2,4]triazolo [4,3-a]pyrido [3,4-e]pyrimidines 9 (Scheme 2). The direct formation of products 8 from the reaction of compound 3 with hydrazonoyl chloride 5 indicates that the intermediate thiohydrazonate esters 6 underwent Smiles rearrangement [13] to give the corresponding thiohydrazides 7, which in situ underwent cyclization with concurrent elimination of hydrogen sulfide gas to give 8 as end products (cf.…”

“…In addition, [1,2,4]triazolo [4,3-a]pyrimidines are pharmacological scaffold that represent a wide range of biological activities such as antitumor [11], and anti-inflammatory [12]. Based on these findings, we report herein the synthesis of [1,2,4]triazolo [4,3-a]pyrido [4,3-d]pyrimidines and [1,2,4]triazolo[4 0 ,3 0 :1,2]pyrimido [4,5-b] [1,6]naphthyridine-5-ones that have not been reported hitherto. Also, we study the biological activity of the newly synthesized compounds against 5a-reductase activity.…”