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. 21, 1989
Filed:
Aug. 29, 1986
Dieter Reuschling, Butzbach, DE;
Adolf Linkies, Frankfurt am Main, DE;
Walter Reimann, Hofheim am Taunus, DE;
Otto E Schweikert, Kelkheim, DE;
Karl E Mack, Weisbaden, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
6-Methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide is prepared by cylcizing acetoacetamide-N-sulfonic acid or its salts with an at least approximately equimolar amount of SO.sub.3 in the presence of a water-immiscible, inert organic solvent and, if appropriate, also an inert, inorganic solvent. In the event that an equimolar amount of SO.sub.3 is employed, working up is effected by adding aqueous sulfuric acid when the cyclization reaction is complete; in the event that the amount of SO.sub.3 employed is more than equimolar, the 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide obtained in the form of the SO.sub.3 -adduct is hydrolyzed by adding water or ice, whereby sulfuric acid is formed from the SO.sub.3 combined in the SO.sub.3 -adduct. The inert, organic solvent is then removed from the resulting multi-phase mixture by distillation, and the 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide is obtained in a pure form from the remaining aqueous sulfuric acid phase by crystallization. Additionally, quite generally, crude 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide is purified by recrystallization from aqueous sulfuric acid. The non-toxic salts of 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2 dioxide--in particular the potassium salt--are valuable synthetic sweetening agents.