Structures of 1,4,2-dithiazolidine 1,1-dioxide and 1,2,4-thiadiazolidin-3-one 1,1-dioxide heterocycles formed from N-benzyl-1-chloromethanesulfonamide and either phenyl isothiocyanate or 3,5-dimethylphenyl isocyanate

Reaction of N-benzyl-1-chloromethanesulfonamide with phenyl isothiocyanate formed N-benzyl-3-phenylimino-1,4,2-dithiazolidine 1,1-dioxide. Crystals of this compound occurred in the monoclinic system, space group P 2(1), a = 26.7099(16) Å, b = 13.2518(5) Å, c = 8.2769(4) Å, β = 97.099(5)^o, Z = 8, with four molecules in the asymmetric unit. The structure confirms a prior assignment that the C = S bond of the isothiocyanate was the reactive moiety. Using the same reaction conditions, 3,5-dimethylphenyl isocyanate was reacted N-benzyl-1-chloromethanesulfonamide to produce a product in 81% yield, which was determined to be 2-benzyl-4-(3’,5’-dimethylphenyl)-1,2,4-thiadiazolidin-3-one 1,1-dioxide. Crystals of this compound are monoclinic, space group P 2(1)/n, a = 5.2243(11) Å, b = 15.844(5) Å, c = 18.628(3) Å, β = 96.72(2)^o, and Z = 4. This product demonstrated that the C = N bond of the aryl isocyanate reacted to form the 1,2,4-thiadiazolidin-3-one 1,1-dioxide ring system.

Graphical Abstract

Heterocyclic rings formed from N-benzyl-1-chloromethanesulfonamide and phenyl isothiocyanate via the C = S bond (structure on the left) or 3,5-dimethylphenyl isocyanate via the C = N bond (structure on the right)