BENZOQUINOLINES .1. SYNTHESIS AND REACTIONS OF SOME NEW FURYLBENZO[H]QUINOLINE DERIVATIVES

A series of new 3-cyano-5,6-dihydro-4-(2-furyl)-2-(substituted)thio-benzo[h]quinolines (IIIa-IIIc, IV, V, VIIa-VIIe and IXa-IXc) have been synthesized from 3-cyano-5,6-dihydro-4-(2-furyl)-benzo[h]quinoline-2(1H)-thione (IIb). Compounds V, VIIa-VIIe and IXa-IXc on treatment with appropriate base underwent smooth cyclization into thieno[2,3-b]-benzo[h]quinolines VI, VIIIa-VIIIe and Xa-Xc, respectively. Hydrolysis of ester VI gave the corresponding acid XI which was converted to oxazinone XII by heating in acetic anhydride. Oxazinone XII, in turn, was recyclized into pyrimidinone derivatives XIII, XIV and XV upon treatment with ammonium acetate, hydrazine hydrate and aniline, respectively. Compounds Xa-Xc were reacted with nitrous acid and with triethyl orthoformate to produce the fused polycyclic compounds XVIa-XVIc and XVIIa-XVIIc. The structures of all newly synthesized compounds were confirmed by elemental analyses and spectral data.