4-Benzyl 1-(2,5-dioxopyrrolidin-1-yl) N-(tert-butoxycarbonyl)-L-aspartate → HCID 131714599, compound

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Reaction Steps

The preceding 30 g of oil in solution in 250 ml of THF are treated with 6.4 ml (50 mM) of NEM and 18.9 (45 mM) of Boc-Asp(OBzl)O Su. The apparent pH is adjusted between 6 and 7 by successive additions of NEM. After 4 hours, the product is isolated by evaporation of the THF, take-up in 400 ml of ethyl acetate followed by the same washings as the preceding homologue (3). The residue after drying and evaporation (36.5 g) is purified by chromatography over a column of silica with dichloromethane as solvent containing from 0 to 1.5% of methanol. 25 g (66%) of product presenting an NMR spectrum in accordance with the expected structure are thus obtained.

Provenance & Evidence