Aerobic thiyl radical addition/cyclization of N-methacryloyl benzamides for the synthesis of isoquinoline-1,3(2H,4H)-dione derivatives.

A highly effective oxidative thiyl radical addition/cyclization of N-methacryloylbenzamides was explored using dioxygen as the sole terminal oxidant without the use of precious and/or toxic transition-metal catalysts. This method provides convenient access to a variety of useful sulfide-containing 4,4-disubstituted isoquinoline-1,3-diones by constructing C-S and C-C bonds in one step.

(E)-4-(4-Hydr-oxy-3-nitro-benzyl-idene-amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one.

In the title compound, C(18)H(16)N(4)O(4), the dihedral angles between the central pyrazole ring and the pendant substituted and unsubstituted aromatic rings are 4.73 (12) and 44.24 (14)°, respectively. An intra-molecular O-H⋯O hydrogen bond occurs. In the crystal structure, an inter-molecular C-H⋯O inter-action may help to consolidate the packing and a short intra-molecular C-H⋯O contact also occurs.

1,2-Bis(2-chloro-benzyl-idene)hydrazine.

The title Schiff base compound, C(14)H(10)Cl(2)N(2), crystallizes with one half-mol-ecule in the asymmetric unit. The mid-point of the N-N bond [1.418 (3) Å] lies on an inversion centre. The mol-ecular skeleton is approximately planar, the largest deviation from the mean plane being 0.143 (4) Šfor the N-bonded C atom. The crystal packing exhibits no classical inter-molecular hydrogen bonds.