Synthesis of novel angularly fused pentacyclic heterocycles of pharmacological interest

Abstract

2-Substituted-4-oxo-naphtho[2,1-<i style="">b</i>]furo[3,2-<i style="">d</i>]pyrimidines <b style="">1a-c</b> on refluxing with phosphorous oxychloride result in the formation of 2-substituted-4-chloronaphtho[2,1-<i style="">b</i>]furo[3,2-<i style="">d</i>]pyrimidines <b style="">2a-c</b>, which on nucleophilic substitution reaction with hydrazine hydrate in ethanol give the required 2-substituted-4-hydrazinonaphtho[2,1-<i style="">b</i>]furo[3,2-<i style="">d</i>]pyrimidines <b style="">3a-c</b>. The compounds <b style="">3a-c</b> are converted into novel angularly fused pentacyclic heterocycles viz. tetrazolo[1,5-<i style="">c</i>]­pyrimido[5,4-<i style="">b</i>]naphtho[2,1-<i style="">b</i>]furan derivatives <b style="">4a-c</b> and triazolo[4,3-<i style="">c</i>]pyrimido[5,4-<i style="">b</i>]naphtho[2,1-<i style="">b</i>]furan derivatives <b style="">5a-i</b> by reacting with appropriate reagents. Condensation of <b style="">3a-c</b> with typical aldehydes afford a series of 4-arylidine­hydrazinonaphtho[2,1-<i style="">b</i>]furo[3,2-<i style="">d</i>]pyrimidines <b style="">6a-o</b>. All the newly synthesized compounds have been characterized by elemental analysis and spectroscopic data and have been evaluated for antimicrobial, anthelmintic, anticonvulsant and antipyretic activities.