Hydrochloric Acid → N-{[(9H-Fluoren-9-yl)methoxy]carbonyl}-D-glutamic acid

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Reaction Steps

In an ice-water bath, a solution of D-glutamic acid (H-D-Glu-OH, 29.4 g, 1.0 eq) in a mixture of acetone and H2O (V/V=1:1) was stirred. After the solid was fully dissolved, NaHCO3 (23.3 g, 1.1 eq) was added in portions, then Fmoc-OSu (67.4 g, 1.0 eq) were added slowly and the reaction was stirred for additional 3 days at r.t. The mixture was then cooled in ice-water bath again, and pH was adjusted to 2-3 with 2.0N HCl. After removal of acetone under reduced pressure, the remaining solution was extracted with AcOEt (400 mL×4). The organic layer was separated and combined, dried with MgSO4 overnight, and concentrated to a small volume under reduced pressure. Then residue was recrystallized with ethylacetate-cyclohexane system. After filtration, 59.8 g of target product was obtained as a white solid with a yield of 81%.

Provenance & Evidence