Hydrochloric Acid → (1S,4R)-Methyl 4-aminocyclopent-2-enecarboxylate hydrochloride

Participants

Reaction Steps

20.0 g (183.3 mmol) of 2-azabicyclo[2.2.1]hept-5-en-3-one, 8.8 g (274.7 mmol) of methanol, and 150 mL of toluene were put into a four-necked flask (300 mL volume) equipped with a hydrogen chloride introducing tube, a thermometer, and an exhaust tube. 6.7 g (183.8 mmol) of hydrogen chloride was introduced into the obtained mixture over a period of 2 hours through the hydrogen chloride introducing tube at room temperature. Following 1 hour of stirring, the precipitated crystals were filtered off with a glass filter. The obtained crystals were dried under reduced pressure to give 30.8 g (173.2 mmol) of cis-4-amino-2-cyclopentene-1-carboxylic acid methyl ester hydrochloride (that is, (1S*, 4R*)-4-amino-1-methoxycarbonyl-2-cyclopentene hydrochloride). The yield was 94.4%.

Provenance & Evidence