Phosgene → HCID 86743550, compound

Participants

Reaction Conditions

Reaction Steps

Into a 2 liter round bottom flask equipped with an oil bath, reflux condenser, and nitrogen atmosphere sparger were charged 1,2,2,6,6-pentamethyl-4-piperidinol (51.2 g, 0.3 mole) and 1 liter of 2-butanone. Freshly distilled phosgene (35 ml, 0.45 mole) was evaporated into the reactor in a stream of nitrogen; a solid precipitate formed immediately. The resulting slurry was heated to reflux which initially was 53° C. but rose gradually over 25 minutes to 77° C. during which time the initially formed solid dissolved. After an additional 25 minutes of reflux at 77° C., the reaction mixture was cooled while being purged of excess phosgene and hydrogen chloride with a nitrogen stream. The ketone solvent was stripped from the product using an aspirator vacuum. The solid obtained was isolated and washed with 300 ml of 1,1,1-trichloroethane; then it was washed a second time with 200 ml of 1,1,1-trichloroethane. The resulting white crystalline solid was dried under high vacuum to give 76.5 g of the chloroformate hydrochloride having an assay of 99.7% (by analysis of hydrolyzable chloride: theoretical 26.24%, found 26.17%) and a corrected yield of 94.4%.

Provenance & Evidence