Bicyclic compounds-correlation of structure with central nervous system (CNS) activity

Abstract

A series of bicyclohydantoins (1) structurally related to pentylenetetrazole (PTZ) (2) were prepared from proline and its ring homologs; piperidine-, perhydroazepine-, and perhydroazocine-2- carboxylic acid. The modification or extension of methods used to ([Structure 1], [Structure 2], [Structure 3]) prepare the precursive mono- and dichlorolactams resulted in an improved method for the synthesis of 3,3-dichloro-2-azacyclotridecanone as well as providing a direct method of converting 2-pyrrolidinone to 3,3-dichloro-2-pyrrolidinone. The N-carbamyl derivatives of proline and piperidine-2-carboxylic acid were isolated and characterized for the fir s t time; and in addition, a much simpler procedure for preparing the phenylthiohydantoin of proline is described. Spectral Information (proton magnetic resonance, Infrared, and mass spectra) useful for characterization of these compounds and related derivatives was obtained. These blcyclohydantolns were tested for CNS response, namely convulsant or anticonvulsant activity in mice. An additional series of compounds (3) structurally similar to PTZ, comprised of indene, its reduced analogs indan and hexahydroindan, and several polyazaindenes was similarly tested. Interesting structure-activity relationships for these convulsant and anticonvulsant structures were observed. These relationships are discussed and structural moieties important for either a convulsant response or an ticonvulsant are given.