Yield:89765-49-1 69%

Reaction Conditions:

Stage #1: ethyl 2-cyanoacetatewith phosphoric acid;sodium nitrite in water at 20 - 40; for 1 h;
Stage #2: with hydrogenchloride in water; for 18 h;

Steps:

P11.A Step A: ethyl (2Z)-2-cvano-2-hvdroxyimino-acetate:

H₃PO4 (1 .83mL, 27mmol) was added to a mixture of ethyl cyanacetate (5g, 44.2mmol) and NaN0₂ (2.87g, 41.5mmol) in 35ml_ of water at room temperature. After the addition, the mixture was warmed to 40°C and stirred for another hour. Then, 3.69ml of hydrochloric acid was added to the mixture and stirring was continued for 18 hours. The mixture was extracted with diethyl ether three times. The combined organic layers were dried over sodium sulfate, filtered and concentrated under vacuum. The residue was purified by column chromatography on silica gel to give the title compound (4.3g, y: 69%) ¹H NMR (300Mz, DMSO-d₆): δ 1 .28 (t, 3H), 4.32 (q, 2H).

References:

WO2015/715,2015,A1 Location in patent:Page/Page column 106