Carbamic acid, ethyl ester → HCID 86690137, compound

Participants

Reaction Steps

Sodium bicarbonate (4.10 g, 48.8 mmol) was added to a stirred solution of 6-amino-2,2,7-trifluoro-4-(prop-2-ynyl)-2H-benzo[b][1,4]oxazin-3(4H)-one (the product of Step 1.6 above, 5.0 g, 19.52 mmol) in absolute ethanol (100 ml) at 0° C. under nitrogen. Thereafter thiophosgene (1.795 ml, 23.42 mmol) was added dropwise under ice-bath cooling, keeping the temperature of the reaction mixture below 10° C. After the addition was complete, the reaction mixture was stirred for 1 h at room temperature, by which time, according to TLC analysis, the reaction was complete. The salts were removed by filtration and washed with ethyl acetate. The filtrate was concentrated in vacuo to yield 6.55 g of crude product, containing ca. 30% ethyl carbamate. Recrystallisation from dichloromethane afforded 3.84 g of the desired product (>90% purity), which was used without further purification.

Provenance & Evidence