Sodium hydride → 4(2,2-Dimethoxyethyloxy)-benzoyl-(2S)-2-benzyloxycarbonylamino-beta-alanine tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

1.8 g (4.34 mmol) of (1.2) were added to a suspension of 176 mg of a 55% strength sodium hydride suspension in oil (4.07 mmol of sodium hydride) in 10 ml of abs. DMF and the mixture was stirred until the evolution of hydrogen was complete (about 30 min). 620 mg (3.7 mmol) of bromoacetaldehyde dimethyl acetal were then added and the mixture was heated at 50° C. for 8 h and at 70° C. for 2 h. After fresh addition of 18 mg of the sodium hydride suspension in oil (0.41 mmol of sodium hydride), the mixture was heated at 70° C. for a further 4 h. After standing overnight, the reaction mixture was concentrated in a rotary evaporator and the residue was partitioned between H2O and CH2Cl2. The organic phase was separated off and dried over MgSO4, and the solvent was removed in vacuo. The residue was chromatographed on silica gel by means of MPLC using heptane/ethyl acetate. (1.3) was obtained as a colorless solid; melting point 115° C.

Provenance & Evidence