Dicyclohexylcarbodiimide → HCID 131714159, compound

Participants

Reaction Steps

A solution of Boc-Ser(tBu)-Asp(OtBu)-Ala-OH.CHA (1.205 g, 2.0 mmol) was extracted with a mixture of EtOAc: 0.5N H2SO4 (10 mL-10 mL). The organic layer was retained, washed with saturated NaCl, dried (MgSO4) and evaporated in vacuo. The resultant free acid in EtOAc:dioxane (5 mL-10 mL) was treated with HOSu (230 mg, 2.0 mmol, 1 eq) and cooled to 0°. To the cold stirring solution DCC (412 mg, 2.0 mm, 1 eq) was added portionwise and stirring proceeded at 0° for 1 hr and at 25° for 48 hr. The reaction mixture was filtered and the filtrate evaporated to dryness and crystallized from isopropanol-petroleum ether. Yield: 631 mg (52.5%); mp 129°-136°; [α]D25 -32.74° (c 1, MeOH); Rf 0.86 (CHCl3 :MeOH:AcOH; 85-10-5); Rf 0.79 (CHCl3 :MeOH:AcOH; 80-5-2). Anal. calc. for C27H44N4O11 (600.67): C, 53.99; H, 7.38; N, 9.33. Found C, 53.85; H, 7.50; N, 9.29.

Provenance & Evidence