Synthesis and crystal structures of halogenated oxathiazolones and an unexpected propanamide.

The known 1,3,4-oxathiazol-2-ones with crystal structures reported in the Cambridge Structural Database are limited (13 to date) and this article expands the library to 15. In addition, convenient starting materials for the future exploration of 1,3,4-oxathiazol-2-ones are detailed. An unexpected halogenated propanamide has also been identified as a by-product of one reaction, presumably reacting with HCl generated in situ. The space group of 5-[(E)-2-chloroethenyl]-1,3,4-oxathiazol-2-one, C 4 H 2 ClNO 2 S, (1), is P2 1 , with a high Z' value of 6; the space group of rac-2,3-dibromo-3-chloropropanamide, C 3 H 4 Br 2 ClNO, (2), is P2 1 , with Z' = 4; and the structure of rac-5-(1,2-dibromo-2-phenylethyl)-1,3,4-oxathiazol-2-one, C 10 H 7 Br 2 NO 2 S, (3), crystallizes in the space group Pca2 1 , with Z' = 1. Both of the structures of compounds 2 and 3 are modeled with two-component disorder and each molecular site hosts both of the enantiomers of the racemic pairs (S,S)/(R,R) and (R,S)/(S,R), respectively.