| 摘要 |
Prodn. of benzisothiazole dioxide of formula (I) and its physiologically acceptable salts, comprise (1) reacting cpd. (II) with alkoxide R'OM (III) under anhydrous conditions at 140-250 deg.C to give salt (Ia); (2) acidification to give hydroxy-salt (Ib) and (3) opt. treating (Ia) or (Ib) with inorganic acid. Y = OH, halo, OR'' or NR3R4; R1 = nucleophilically displaceable gp. or OR; R2 = H or COOH; M = equiv. of Gp.IA or IIA metal; R, R' and R'' = 1-25C alkyl, cycloalkylalkyl or aralkyl, opt. interrupted by heteroatoms, substd. by OH or contg. double bonds; R3 and R4 = H; 1-8C alkyl or alkenyl (opt. substd. by one or more OH or interrupted by O, S or (alkyl)N); or phenyl (opt. substd. by alkyl, halo or OH), or R3 and R4 together complete a 4-8 membered heterocyclic ring. Pref. the first step is pref. at 140-220 deg.C, esp. using R'OH as solvent. Initially, displaceable gps. (Y and/or R1) are replaced by R'O and if R2 = COOH, decarboxylation occurs. Where R1 = OR and Y is other than a displaceable gp., at least 2 equiv. bases are used; if R1 is a displaceable gp. and Y = halo, an extra equiv. of base is needed, and if R2 = COOH, two further equivs. of base. The reaction is pref. under inert gas. |
