Nitrogen → 5,7-Dichloro-1-methyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one

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Reaction Steps

In a 1 L 2 neck RBF equipped with mechanical stir, condenser and N2 inlet, 7-chloro-1-methyl-3,4-dihydro-1H-benzo[e][1,4]diazepine-2,5-dione (42.5 g, 0.189 mol) was suspended into 400 ml, of toluene. To this was added N,N-dimethylanaline (45.5 g. 0.375 mol) followed by the addition of POCl3 (29 g, 0.189 mol) and the reaction mixture stirred for 3 min (RT). Reaction flask was placed in a 90° C. oil bath and the reaction mixture stirred/heated for 7 h and then at RT for 9 h. Reaction was quenched by adding 500 mL of ice water and stirred for 15 min. Organic layer was separated and quickly washed with cold 0.5 M HCl (300 mL), cold water (300 mL), and then cold saturated NaHCO3 (300 mL). Organic layer was dried (MgSO4), filtered and concentrated on a rotary evaporator to give 40 g of yellow solid. Yield 87.5%. 1H NMR (300 MHz, DMSO-d6) δ 3.25 (s, 3H), 3.8-3.9 (s, 1H, br), 4.3-4.4 (s, 1H, br), 7.4 (d, 1H), 7.7-7.8 (m, 2H).

Provenance & Evidence