Pyridine → HCID 21525327, compound

Participants

Reaction Steps

A suspension of 21.5 g of N-(ethylaminomethyl)-benzamide hydrochloride (0.1 mole) in 300 ml of water is neutralised at 0°-25°C with 50 ml of 2 normal sodium hydroxide solution (0.1 mole). Extraction is performed with ethyl acetate, the organic phase is dried over magnesium sulphate and the solvent is evaporated off. The residue is taken up in 150 ml of tetrahydrofuran and the solution is treated dropwise with 9.9 g of phosgene (0.1 mole) in 150 ml of tetrahydrofuran. The addition is effected at 0°-25°C over the course of 1 hour. Then a solution of 15.8 g (0.2 mole) of pyridine in 150 ml of tetrahydrofuran is added over the course of a further hour. Stirring of the reaction mixture is continued for 2 hours and it is then refluxed for 3 hours. After the reaction mixture has cooled, the precipitate which has formed is filtered off and the filtrate is evaporated to dryness. The residue is taken up in chloroform and washed first with sodium bicarbonate solution and then with water. The solvent is evaporated off and crystallisation of the residue from ethyl acetate/n-hexane yields 6-phenyl-3-ethyl-3,4-dihydro-2H-1,3,5-oxadiazin-2-one with a melting point of 96°-98°C (compound 1).

Provenance & Evidence