Synthesis, anticonvulsant and antihypertensive activity of diastereomeric 9,10-dimethoxy-1,3,4,6,7,11b-hexahydrospiro-[benzo[a]quinolizin-2,4′-imidazolidine]-2′,5′-diones

Abstract

The synthesis of the 2 S, 11b S ( 2) and 2 R, 11b S ( 3) diastereoisomers of the 9,10-dimethoxy-1,3,4,5,6,11b-hexahydrospiro[benzo[a]quinolizin-2,4′-imidazolidine]-2′,5′-dione system was achieved using the Bucherer-Bergs and Read hydantoin syntheses respectively. Alternatively, the 2 R, 11b S isomer was prepared by treating the appropriate aminonitrile with chlorosulphonyl isocyanate, followed by acid hydrolysis. Compound 3 showed good anticonvulsant activity against pentamethylenetetrazole-induced seizures. Its behaviour is discussed in comparison with that of phenytoin. Both compounds were inactive as antihypertensives.