Synthesis of a new range of heterocycles containing N O and or P as heteroatoms

Abstract

Recently, a number of reports on benzoxazine and benzoxazaphosphinine derivatives have appeared in the literature. This is due to partially the fact that 1,3-oxazine derivatives show interesting pharmacological activity. newlineThe first part of the present work deals with the synthesis of 2-[(Arylimino)-methyl]-phenols. Since, Analogous to carbon-carbon and carbon-oxygen double bonds, carbon-nitrogen double bond has been an active site of study in recent times. The reactivity of the carbon-nitrogen double bond lies in between that of the carbonyl and olifinic functions. Unlike carbon-carbon double bond, carbon-nitrogen double bond has an additional lone pair of electrons, which leads to its distinctive properties from carbon carbon double bond. For the present study, we had prepared the various imines/ sulfonylimines by reacting variously substituted arylamines/ sulfonylamines with salicyldehyde. These imines/ sulfonyimines were subjected to reduction by sodium borohydride in alcohol to give resultant N-(2-hydroxy)-benzylarylamines/ aryl sulfonamide. newlineThe second part deals with the synthesis of 3-Aryl-3,4-dihydro-2H-benz[e]-1,3-oxazine/ 6-Bromo-3-aryl-3,4-dihydro-2H-benz[e]-1,3-oxazines. From various reported synthetic methods, the condensation of substituted 2-hydroxybenzylamine with formaldehyde seemed the most reliable for the synthesis of variously substituted 3-aryl-3,4-dihydro-2H-benz[e]-1,3-oxazines. During our study, we have observed that the molar ratio of formaldehyde plays an important role.