SYNTHESIS OF NEW RING SYSTEMS: ISOMERIC 1,2,4-TRIAZOLOPYRIMIDO [4″,5″:4′,5′]THIENO[3′,2′:5,6]PYRIDO[3,2C]CINNOLINES AND OTHER RELATED SYSTEMS

3-Amino-2-Cyano-4-(p-tolyl)thieno[3′,2′:5,6]pyrido[3,2-c]cinnoline 1 underwent ring closures with formamide and carbon disulphide to afford pyrimidothienopyridocinnaline 2 and its pyrimido-9,11-thione derivative 3, respectively. Treatment of 1 with triethylorthoformate followed by hydrazine hydrate produced 10-amino-11-imino-pyrimido system 5, which in turn reacted with triethylorthoformate, acetic acid, carbon disulphide, and acetylacetone to cyclize into the systems, 1,2,4-triazolo, 2-methyltriazolo, triazolo-2-thione, and 1,2,4-triazepinopyrimido thienopyridocinnolines 6– 8, 11, respectively. Similarly, 3-amino-2-carboxamido-thienopyridocinnoline 12 was reacted with triethylorthoformate to give pyrimidothienopyridocinnoline-11-one 13, which was treated with phosphorous oxychloride and then hydrazine hydrate to produce 11-hydrazinopyrimido system 16. Treatment of 16 with triethylorthoformate, acetic anhydride, carbon disulphide, and ethyl chloroformate afforded the systems, 1,2,4-triazolopyrimidothienopyrido-cinnoline derivatives 16– 18, 20, respectively.