Dichloromethane → 26409-02-9

Participants

Reaction Steps

To a cold (ice bath) solution of 85.8 g (0.868 mole) of phosgene in 500 ml of methylene chloride was added dropwise a solution of 100 g (0.868 mole) of 4-hydroxy-1-methylpiperidine in 250 ml of methylene chloride at such a rate that the internal temperature did not exceed 12° C. A crystalline solid precipitated during addition. The mixture was stirred in the cold for 1 hr after addition was complete and then 120.8 ml (87.7 g, 0.868 mole) of triethylamine was added dropwise at such a rate that the internal temperature did not exceed 25° C. The mixture was stirred at ambient temperature overnight and then diluted with 500 ml of toluene. The methylene chloride was removed by distillation and the resultant mixture was heated at reflux for 2 hr. The mixture was cooled and treated with 500 ml of 1N hydrochloric acid. The layers were separated and the organic layer was washed successively with 500 ml of 1N hydrochloric acid, 500 ml of a 4% sodium hydroxide solution and once with brine, dried over anhydrous sodium sulfate and concentrated to give an oil as residue. The oil was subjected to vacuum distillation to give 34.4 g (22%) of clear oil (b.p. 147°-150° C. at 0.4 mm).

Provenance & Evidence