Methyl cyanoacetate → 2-Methoxy-4-imino-6-oxo-dihydropyridine

Participants

Reaction Steps

Compound III is synthesized according to the procedure of Pfeiderer (Pfeilderer, W. (1957) Chem. Ber., 90:2272-2276) as follows. 12.2 g of o-methylisourea hydrochloride (110.6 mmol), 11.81 mL methylcyanoacetate (134 mmol), 12.45 g of sodium methoxide (230.5 mmol) and 80 mL of methanol are placed in a 250 mL round bottom flask. The suspension is stirred and refluxed for 5 hours at 68°-70° C. After cooling at room temperatute, the suspension is filtered through a sintered glass funnel (Pyrex, 40-60 ASTM, 60 mL), and the NaCl on the filter is washed with methanol. The filtrate is filtered by gravity through a Whatman™ no. 1 paper in a 500 mL round bottom flask, and the solvent is evaporated under reduced pressure with a rotary evaporator at 50° C. The residue is solubilized with warm distilled water, and the product is precipitatedd by acidification to pH 3-4 with glacial acetic acid. After 2 hours (or overnight) at room temperature, the suspension is filtered under vacuum through a sintered glass funnel (Pyrex, 40-60 ASTM, 60 mL). The product is washed with water, acetone, and dried. The product is recrystallized with water as the solvent and using charcoal for decolorizing (activated carbon, NoritrA<100 mesh, decolorizing). The yield is 76%.

Provenance & Evidence