Water mediated synthesis of various [1,3]oxazine compounds using alum as a catalyst

A simple, efficient, and practical procedure for the synthesis of various substituted 2,3-dihydro-2-phenyl-1H-naphtho[1,2-e][1,3]oxazines and 3,4-dihydro-3-phenyl-2H-naphtho[2,1-e][1,3]oxazines using KAl(SO4)(2)center dot 12H(2)O (alum) as a non-toxic, reusable, inexpensive, and easily available catalyst is described using water as a solvent. These improved reaction conditions allow the preparation of a wide variety of substituted [ 1,3] oxazines in high yields and purity under mild reaction conditions.