The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 2010
Filed:
Aug. 02, 2007
Akira Saito, Myoko, JP;
Yuki Ishiguro, Myoko, JP;
Yasushi Yamamoto, Myoko, JP;
Daicel Chemical Industries, Ltd., Osaka-shi, JP;
Abstract
A high quality 3,4-dihydro-1,2,3-oxathiazin-4-one-2,2-dioxide compound or a salt thereof is obtained easily and efficiently. When the compound represented by the following formula (2) [Formula 2] (wherein, R, R, and Rare hydrogen atom or an organic group inert to the reaction, and X is hydrogen atom) or a salt thereof is produced by cyclization of a mixture of β-ketoamide-N-sulfonic acid represented by the following formula (1)[Formula 1] or a salt thereof and an inert solvent and a mixture of acid anhydride and an inert solvent, and by subsequent hydrolysis of the product, a step of (A) hydrolyzing the reaction product obtained by the cyclization by mixing with an aqueous solution of sulfuric acid so as a concentration of sulfuric acid in an aqueous phase after the hydrolysis would become 30% by weight or more, and then separating an organic phase and an aqueous phase, or a step of (B) washing the organic phase liquid after the hydrolysis with an aqueous solution of sulfuric acid with a concentration of 30% by weight or more is at least carried out.