Pyridine → p-Toluenesulfonic acid (S)-2-methylbutyl ester

Participants

Reaction Steps

In 300 ml flask were charged 100 ml of pyridine and 40 g of (S)-2-methylbutanol (98 ee %) (produced by Tokyo Chemical Industry Co., Ltd.), and the mixture was cooled to 15° C. or less. To the mixture was added 104 g of p-toluenesulfonyl chloride at that temperature over 10 minutes. The inner temperature was returned to room temperature, at which the mixture was allowed to react for 2 hours. Water was added thereto, and the reaction mixture was extracted with ethyl acetate. The extract was washed twice with a saturated sodium chloride aqueous solution. The solvent was removed by distillation under reduced pressure to obtain 104.6 g of (S)-2-methylbutyl p-toluenesulfonate. The resulting compound was put in a 1 l flask, and 300 ml of dimethylformamide (hereinafter abbreviated as DMF) and 47.7 g of lithium bromide (monohydrate) were added thereto, followed by allowing the mixture to react at 60° C. for 5 hours. Water was added thereto, and the reaction mixture was extracted with diethyl ether. The extract was washed twice with water, and diethyl ether was removed by distillation to obtain 60.2 g of a crude product. The crude product was purified by distillation to obtain 45.45 g (66.2%) of the titled compound (b.p.: 55° C./100 mmHg).

Provenance & Evidence