Organic compounds -- part of the class 532-570 series – Organic compounds – Chalcogen in the nitrogen containing substituent
Patent
1983-03-25
1984-10-16
Ford, John M.
Organic compounds -- part of the class 532-570 series
Organic compounds
Chalcogen in the nitrogen containing substituent
C07D40112, C07D41712
Patent
active
044776616
ABSTRACT:
The present invention provides a process for the preparation of 4-hydroxy-3-(heterocyclocarbamoyl)-2H-1,2-benzothiazine-1,1-dioxides of the general formula: ##STR1## wherein R.sub.1 is a hydrogen atom or a methyl radical, R.sub.2 is a nitrogen-containing heterocyclic radical and R.sub.3 is a hydrogen or halogen atom or a methyl radical, and of the alkali metal, alkaline earth metal and amine salts thereof, by the reaction of an amine-substituted, nitrogen-containing heterocyclic compound with a halo-acetyl halide, reaction of the intermediate thus obtained with sodium benzoic acid sulphimide, ring expansion of the benzoisothiazole ring to give a benzothiazine ring and, in case R.sub.2 is to be an isoxazolyl radical, reverse rearrangement of the oxadiazole-ring formed by ring expansion to the isoxazolyl ring, wherein (in a one-pot reaction A) the reaction of an amine-substituted, nitrogen-containing heterocyclic compound with a halo-acetyl halide is carried out, without the addition of a base, in boiling ethyl acetate, the intermediate formed is, without isolation, reacted with sodium benzoic acid sulphimide and the reaction product isolated, whereafter, in a one-pot reaction B, the reaction product from the one-pot reaction A is reacted in a dipolar aprotonic solvent under an atmosphere of a protection gas with a strongly basic alkali-alkohole and thereafter with so much acid that about 2 equivalents of base remained unneutralized in the reaction solution and, if desired, the benzothiazine ring is N-methylated in the usual manner and the product obtained is, if desired, converted in known manner into an alkali metal, alkaline earth metal or amine salt.
REFERENCES:
patent: 3501466 (1970-03-01), Rasmussen
patent: 3770733 (1973-11-01), Sianesi et al.
patent: 3822258 (1974-07-01), Zinnes et al.
patent: 4116964 (1978-09-01), Zinnes et al.
patent: 4376119 (1983-03-01), Ozaki et al.
Geibel Wolfram
Herrmann Wolfgang
Satzinger Gerhard
Daignault Ronald A.
Ford John M.
Warner-Lambert & Company
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