Process for producing saccharin
AssigneeIhara Chemical Industry Co., Ltd.
InventorsWataro Koike, Takahiro Kimoto, Sadayoshi Matsui
Life of this patent
Estimating the term…
Abstract
1,2-Benzoisothiazole-3-on-1, 1-dioxide having the formula ##STR1## wherein X represents hydrogen, halogen, nitro, lower alkyl or lower alkoxy and Y represents hydrogen, halogen, lower alkyl, or lower alkoxy is prepared by reacting phosgene with an o-sulfobenzoic acid compound having the formula: ##STR2## or an alkali metal salt or alkaline earth metal salt thereof in the presence of dimethylformamide, thereby producing a mixture of a dichlorotolylsultone and a chlorosulfonylbenzoylchloride; (b) reacting the reaction products of step (a) with an alcohol of the formula ROH wherein R represents a lower alkyl group; and then (c) reacting the product of step (b) with ammonia.
Claims11
A process for producing 1.2-benzoisothiazole3-on-1.1-dioxide having the formula:
- ##STR37## wherein X represents hydrogen, halogen, nitro, lower alkyl or lower alkoxy and Y represents hydrogen, halogen, lower alkyl, or lower alkoxy which comprises:
- (a) reacting phosgene with an o-sulfobenzoic acid compound having the formula:
- ##STR38## or an alkali metal salt or alkaline earth metal salt thereof in the presence of dimethylformamide, thereby producing a mixture of a dichlorotolylsultone and a chlorosulfonylbenzoylchloride;
- (b) reacting the reaction products of step (a) with an alcohol having the formula ROH wherein R represents a lower alkyl group;
- (c) reacting the reaction product of step (b) with ammonia to form the ammonium salt of said 1.2-benzoisothiazole-3-on-1.1dioxide;
- and converting said ammonium salt to said 1.2-benzoisothiazole-3-on-1.1-dioxide.
Dependencies are inferred from the claim text.