Process for the preparation of 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide
AssigneeHoechst Aktiengesellschaft
InventorsJoachim Schutz, Otto E. Schweikert
Life of this patent
Estimating the term…
Abstract
Acetoacetamide-N-sulfonic acid and its salts are cyclized with at least approximately the equimolar amount of SO.sub.3 in short times, preferably in special apparatus, to give 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide. In the case where more than the equimolar amount of SO.sub.3 is used, the latter compound is produced as an SO.sub.3 adduct which then needs to be hydrolyzed; the hydrolysis also takes place in short times and, particularly advantageously, in apparatus of the same type as for the cyclization. The non-toxic salts, especially the potassium salt - of 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide are valuable synthetic sweeteners.
Claims20
A process for the preparation of 6-methyl-3,4-dihydro1,2,3-oxathiazin-4-one 2,2-dioxide which comprises ring closure of acetoacetamide-N-sulfonic acid or one of its salts - dissolved in an equimolar amount to 20-fold molar excess of SO.sub.3 at a temperature of from -70.degree. C. to +175.degree. C. in a reactor within a reactor hold-up time not exceeding 10 minutes after which the ring closure product is passed on out of the reactor or, in the case where more than the equimolar amount of SO.sub.3 is used, the SO.sub.3 adduct of the ring closure product is passed on for hydrolysis, to yield the 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide.
Dependencies are inferred from the claim text.