2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 3-Ethyl 5-methyl 2-amino-6-methyl-4-(p-tolyl)pyridine-3,5-dicarboxylate

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Reaction Steps

A solution of 3-ethyl 5-methyl 2-amino-6-methyl-4-(p-tolyl)-1,4-dihydropyridine-3,5-dicarboxylate (2 g, 6.05 mmol) in dichloromethane (DCM) (30 ml) was treated with DDQ (1.374 g, 6.05 mmol) and stirred at rt for 1.5 hours. The reaction was filtered through a pad of celite and washed with DCM. The filtrate was diluted with sat. NaHCO3, extracted with DCM, washed with brine, dried with Na2SO4, filtered, and concentrated to afford 3-ethyl 5-methyl 2-amino-6-methyl-4-(p-tolyl)pyridine-3,5-dicarboxylate (1.9145 g, 5.83 mmol, 96% yield) as brown solid: 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 7.14 (d, J=7.8 Hz, 2 H), 7.08-7.00 (m, 2 H), 6.05 (br. s., 2 H), 3.86 (q, J=7.2 Hz, 2 H), 3.45 (s, 3 H), 2.43 (s, 3 H), 2.37 (s, 3 H), 0.69 (t, J=7.2 Hz, 3 H); LCMS (m/z) ES+=329 (M+1).

Provenance & Evidence