Process for the preparation of 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide and for the purification thereof

US4804755A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Dieter Reuschling · Rockenberg, DE
• Adolf Linkies · Frankfurt, DE
• Walter Reimann · Hofheim, DE
• Otto E. Schweikert · Kelkheim, DE
• Karl E. Mack · Wiesbaden, DE
• Wolfgang Ebertz · Hattersheim, DE

Key dates

• Filing date: Aug 29, 1986
• Grant date: Feb 14, 1989
• Expiry date: Aug 29, 2006

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D291/06
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The non-toxic salts of 6-methyl-3,4-dihydro-1,2,3-oxothiazin-4-one 2,2-dioxide are prepared by cyclizing acetoacetamide-N-sulfonic acid or its salts with an at least approximately equimolar amount of SO3 in the presence of a water-immiscible, inert organic solvent and, if appropriate, also an inert inorganic solvent, hydrolyzing the 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide obtained in the form of the SO3-adduct after the cyclization reaction, in the event that the amount of SO3 employed is more than equimolar, purifying the organic phase (which has separated out) by extraction with a small volume of water or dilute aqueous sulfuric acid, preferably only with water, and isolating, by neutralization with bases, the non-toxic salts of the 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide from the organic phase thus purified. The said salts are obtained in this process in an extremely pure form; they are valuable synthetic sweetening agents. The potassium salt is known as acesulfam (K).