Dimethylamine → 3-[(Dimethylamino)diazenyl]-5-(tert-butyl)selenophene-2-carbonitrile

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-amino-5-(tert-butyl)selenophene-2-carbonitrile (1 g, 4.3 mmol), prepared as described in Example 13 step a), fluoroboric acid (2.7 mL, 45% aqueous, 17.5 mmol), water (10 mL) and acetone (25 mL) was added sodium nitrite (0.33 g, 4.8 mmol) in portions for 5 min at 0° C. After stifling at 0-5° C. for 2.5 h, the reaction mixture was added to the solution of potassium carbonate (2.3 g, 16.64 mmol) and dimethylamine (3.5 mL, 40%, 15.76 mmol) in water (20 mL) at 0° C. The mixture was stirred at 0-5° C. for 2 h and poured into ice cold water. The solution was extracted with chloroform (3×200 mL) and the combined organic layer was washed with water, brine and dried over sodium sulfate. The solution was filtered and evaporated the solvent. The residue was chromatographed over silica gel column using hexane-EtOAc (95:5) as eluents to give the product, which was recrystallized from hexane-chloroform as a red color solid (15 mg, 12%), mp 58-60° C. IR (neat) νmax 3437, 2200, 1633, 1339, 1219, 1178, 1094 cm−1; 1H NMR (400 MHz, CDCl3): δ 7.26 (1H, s, H-4), 3.52 (3H, s, —NCH3), 3.22 (3H, s, —NCH3), 1.38 (9H, s, tert-butyl); 13C NMR (100 MHz, CDCl3): δ 171.0, 161.5, 117.3, 116.4, 95.2, 43.3, 37.3, 36.2, 32.4; LC-MS (positive ion mode): m/z 283, 285 (M+H)+.

Provenance & Evidence