Abstract
Five new 3',4'-substituted-spiro[isochromene-3,5'-isoxazolin]-4(1H)-ones 7-11 have been prepared in the reaction of p-R-benzadoxime 2-6 with 3-para-methoxy-benzylidene-isochroman-4-one 1. The reaction occurs by a 1,3-dipolar cycloaddition mechanism which leads to the regiospecific formation of various spiro-isoxazolines 7-11. It is concluded that rigid (O-1'-C-O-2) group may be responsible for the biological activity observed in antitubercular test with these hyper inter-organised spiro-isoxazoline derivatives. However, subtle alteration by addition of a substituted aryl groups affecting the charge distribution of the terminal heteroatom O-1' confers significant improvements in biological effects.