Triethylamine hydrochloride → 40671-34-9

A four-necked flask (11) was charged with 3-buten-1-ol (72 g), dry tetrahydrofuran (400 ml), and methanesulfonyl chloride (126 g), and the mixture was subjected to a nitrogen stream. After sufficiently cooling the flask with ice water, triethylamine (111 g) was slowly added dropwise to the flask from a dropping funnel After the dropwise addition, the mixture was stirred for about 30 minutes while cooling the flask with ice water, and then stirred at room temperature for about 4 hours. After completion of the reaction, 100 ml of tetrahydrofuran was added to the mixture, and salts (triethylamine hydrochloride) produced by the reaction were filtered off Most of the tetrahydrofuran was evaporated from the filtrate using an evaporator. After the addition of 200 ml of diethyl ether to the residue, the mixture was sequentially washed with 5% hydrochloric acid, a saturated sodium bicarbonate aqueous solution, and a saturated sodium chloride solution, and dried over anhydrous magnesium sulfate, and magnesium sulfate was filtered off Diethyl ether was evaporated from the filtrate using an evaporator to obtain 126 g of 4-methanesulfonyloxy-1-butene (hereinafter referred to as “mesylate”) as a yellowish brown oil (yield: 84%).