1,1'-(9,9-Dimethyl-9H-xanthene-4,5-diyl)bis(1,1-diphenylphosphine) → 5-cyano-N-(2,4-dimethoxybenzyl)-N-(1,2,4-thiadiazol-5-yl)naphthalene-2-sulfonamide

Participants

Reaction Conditions

Reaction Steps

A microwave vial was charged with Xantphos (44.5 mg, 0.077 mmol) and Pd2(dba)3 (35.2 mg, 0.038 mmol). The vessel was flushed with Ar (g), then DMF (3843 μl) was added. The vessel was sealed and heated in a microwave reactor at 120° C. for 10 min. The mixture was cooled, then a solid mixture of 5-bromo-N-(2,4-dimethoxybenzyl)-N-(1,2,4-thiadiazol-5-yl)naphthalene-2-sulfonamide (Intermediate D; 200 mg, 0.384 mmol) and dicyanozinc (226 mg, 1.922 mmol) was added. The vial was re-sealed and heated in the microwave for 3 h at 120° C. The mixture was then diluted with water and extracted with EtOAc (3×). The combined organic extract was dried over sodium sulfate, filtered, and concentrated. The residue was purified by silica gel chromatography on a 40-g column with 50 to 100% EtOAc/Heptane to give 5-cyano-N-(2,4-dimethoxybenzyl)-N-(1,2,4-thiadiazol-5-yl)naphthalene-2-sulfonamide as an off-white solid. This material was dissolved in DCM (1 mL) and TFA (0.5 mL). The mixture was stirred for 4 h, then diluted with 2-propanol and concentrated. The residue was purified by silica gel chromatography (12-g, with 0 to 10% MeOH/DCM) to give 5-cyano-N-(1,2,4-thiadiazol-5-yl)naphthalene-2-sulfonamide (12.98 mg, 0.041 mmol, 67.5% yield) as an off-white solid. 1H NMR (400 MHz, DMSO-d6) δ ppm=8.70 (br. s., 1H), 8.60 (d, J=9.0 Hz, 1H), 8.48 (br. s., 1H), 8.34 (d, J=7.1 Hz, 1H), 8.28 (d, J=8.2 Hz, 1H), 8.10 (d, J=8.5 Hz, 1H), 7.88-7.77 (m, 1H); m/z (ESI) 317.2 (M+H)+.

Provenance & Evidence