1,5-Naphthalenedisulfonic acid → (+/-)-Methyl alpha-fluoromethylhistidinate 1,5-naphthalene disulfonate

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Reaction Steps

Into a Fisher-Porter tube there was charged 5 g of (±) α-fluoromethylhistidine hydrochloride, 100 ml of methanol, 45 ml of methyl orthoformate and 9.7 g of naphthalene-1,5-disulfonic acid. The tube was sealed and heated in a steam bath overnight. The tube was cooled in an ice bath and the crystalline product (naphthalene-1,5 disulfonic acid salt of α-fluoromethylhistidine) was filtered and returned to the Fisher-Porter tube. Methanol (120 ml), methyl orthoformate (55 ml), and naphthalene-1,5 disulfonic acid (9.4 g) were added, the tube sealed and heated overnight in a steam bath, then cooled in an ice bath for ca. 5 hours. The crystals of (±)-methyl α-fluoromethylhistidinate 1,5-naphthalene disulfonate formed were filtered, washed with cold methanol and diethyl ether and dried in vacuo.

Provenance & Evidence