Hydrochloric Acid → (+/-)-1-BOC-amino-2-cyclopentene-4-carboxylic Acid

Participants

Reaction Steps

16.4 g of crude (±)-1-amino-2-cyclopentene-4-carboxylic acid hydrochloride (prepared as in J. Org. Chem. 1981, 46, 3268) were dissolved in a mixture of 80 ml of water and 80 ml of dioxane at room temperature under nitrogen. The mixture was then adjusted to pH 14 with 1N NaOH, and a diethyl ether solution of tert-butyloxycarbonyl fluoride (BOC-F, 20% excess) was added (BOC-F prepared as in Synthesis 1975, 599). The mixture was stirred for a further 5 h at room temperature. The pH was adjusted to 2 with conc. HCl. After distillation of the organic solvents, 50 ml of water were added to the residue, and the mixture was extracted 3 times with 100 ml of ethyl acetate. The organic phase was evaporated to 50 ml and diluted with 25 ml of toluene. After cooling (0-10° C.), the title compound was filtered and dried. 14.3 g of product were obtained. The yield was 63%.

Provenance & Evidence