The synthesis of meloxicam is performed as follows: The reaction of benzisothiazolo-3(2H)-one-1,1-dioxide (I) with methyl chloroacetate gives the methyl 2(3H)-acetate derivative, which is isomerized with sodium methoxide in toluene/tert-butanol yielding methyl 4-hydroxy-2H-1,2-benzothiazine-3-carboxylate-1,1-dioxide. The subsequent methylation with methyl iodide in methanol yields 2-methyl compound (II). Finally, this compound is treated with 2-amino-5-methylthiazole in xylene.