Pyridine → HCID 59996114, compound

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Reaction Steps

A stirred solution of 14.5 g. (0.052 mole) of N-carbobenzyloxy-4-hydroxy-L-proline, methyl ester in 30 ml. of pyridine is treated dropwise at -5° to -8° with a solution of 11 g. (0.058 mole) of tosyl chloride in 15 ml. of pyridine. The pale yellow solution is stored in the cold for 3 days, then added with stirring to 300 ml. of ice-cold 2 N hydrochloric acid. The precipitated gum is extracted with 200 ml. of chloroform. The aqueous phase is extracted with additional chloroform (3×100 ml.). The organic layers are combined, dried (MgSO4), and the solvent evaporated to give a pale yellow viscous oil. The oil is dissolved in 100 ml. of methanol and diluted to 400 ml. with water to precipitate the product as an oil which gradually crystallizes on seeding, rubbing, and cooling: yield 17.4 g. (77%); m.p. 62°-65°. Following crystallization from 85 ml. of isopropanol, the colorless solid N-carbobenzyloxy-4-tosyloxy-L-proline, methyl ester weighs 15.9 g. (70%); m.p. 67°-69°; [α]D26 -30° (c=1; methanol).

Provenance & Evidence