Studies in spiroheterocycles, Part XV . Investigation of the reaction of 3‐(2‐oxocycloalkylidene)‐indol‐2‐ones with thiourea and urea derivatives

The reaction of 3‐(2‐oxocycloalkylidene)indol‐2‐one 1 with thiourea and urea derivatives has been investigated. Reaction of 1 with thiourea and urea in ethanolic potassium hydroxide media leads to the formation of spiro‐2‐indolinones 2a‐f in 40–50% yield and a novel tetracyclic ring system 4,5‐cycloalkyl‐1,3‐diazepino‐[4,5‐ b ]indole‐2‐thione/one 3a‐f in 30–35% yield. 3‐(2‐Oxocyclopentylidene)indol‐2‐one afforded 5′,6′‐cyclopenta‐2′‐thioxo/ oxospiro[3 H ‐indole‐3,4′(3′ H )pyrimidin]‐2(1 H )‐ones 2a,b and 3‐(2‐oxocyclohexylidene)indol‐2‐one gave 2′,4′a,5′,6′,7′,8′‐ hexahydro‐2′‐thioxo/oxospiro[3 H ‐indole‐3,4′ (3′ H )‐quinazolin]‐2(1 H )‐ones 2c‐f . Under exactly similar conditions, reaction of 1 with fluorinated phenylthiourea/cyclohexylthiourea/phenylurea gave exclusively spiro products 2g‐1 in 60–75% yield. The products have been characterized by elemental analyses, ir pmr. 19 F nmr and mass spectral studies.