Heterocyclisation of <i>N</i>-(2-cycloalk-1-en-1-yl-6-methylphenyl)-<i>N</i>-(2-hydroxyethyl)-4-methylbenzenesulfonamides to benzoxazocines

Abstract

The article cover the results of a study on the synthesis of benzoxazocines condensed with cycloalkenes. By reacting the corresponding N -tosyl-2-(1-cycloalken-1-yl)anilines with 2-bromoethyl ester of acetic acid, the products of substitution of bromine for the arylamide group were synthesized. The resulting esters were converted by alkaline hydrolysis into N -(2-cycloalk-1-en-1-yl-6-methylphenyl)- N -(2-hydroxyethyl)-4-(methylbenzene)sulfonamides. The interaction of these amides with molecular bromine gives benzo[ e ]cycloalka[ g ][1,4]oxazocine N -tosylates with predominant a R *, R *-stereochemistry, which in solution slowly turn into a S *, R *-atropisomers reaching a ratio of 2.7:1 in the case of cyclohexenyl and 1.4:1 in the case of cyclopentenyl homologues.