| abstract |
A method produces a 3,4-dihydro-1,2,3-oxathiazin-4-one-2,2-dioxidencompound of following formula (2):n nwherein R 1 and R 2 are the same as or different from eachnother and are each hydrogen atom or an organic group inertnto the reaction; and R 3 is hydrogen atom or an organic groupninert to the reaction, or a salt thereof, by subjecting anbeta-ketoamide-N-sulfonic acid of following Formula (1):n nwherein R 1 , R 2 and R 3 are as defined above; and X is hydrogennatom, or a salt thereof, to cyclization in the presence ofnan acid anhydride with or without further subjecting thencyclized product to hydrolysis, in which the cyclization isncontinuously carried out using a continuous flow reactor. |