KBrO3-Promoted Cross-Dehydrogenative Coupling Reaction: An Odorless Regioselective Sulfenylation of Imidazoheterocycles in Water.

A regioselective metal-free sulfenylation of imidazoheterocycles with heterocyclic thiols or thiones has been achieved using a cross-dehydrogenative coupling method in water. In addition, the procedure has several advantages including green solvents, free of foul-smelling sulfur sources, and mild conditions, thus providing considerable application potential in the pharmaceutical industry.

6-Amino-3-methyl-4-(3-nitro-phen-yl)-1-phenyl-1H,4H-pyrano[2,3-c]pyrazole-5-carbonitrile.

The title compound, C(20)H(15)N(5)O(3), was synthesized by the one-pot reaction of a four-component reaction protocol in aqueous medium. The pyrano[2,3-c]pyrazole system is essentially planar, with a maximum deviation of 0.026 (2) Å. The 3-nitro-phenyl and phenyl rings make dihedral angles of 81.11 (5) and 13.36 (1)°, respectively, with the mean plane of the pyrano[2,3-c]pyrazole ring. The crystal structure is stabilized by N-H⋯N hydrogen bonds, which form infinite chain propagating along the c axis and by N-H⋯O hydrogen bonds, which form infinite chains propagating along the a axis. There are also N-O⋯N-C dipole-dipole inter-actions along the a axis with an O⋯N distance of 3.061 (3) Å, which is shorter than that of the N-H⋯O hydrogen bond [3.196 (3) Å].