Patent attributes
The present invention provides improved processes for the preparation of Bortezomib, tert -butyl[1-({(1S)-3-methyl-1-[(3aS,4S,6S,7aS)-3a,5,5-trimethylhexahydro-4,6-methano-1,3,2-benzodioxaborol-2-yl]butyl}amino)-1-oxo-3-phenylpropan-2-yl]carbamate of formula (IV) and N-{(1S)-3-methyl-1-[(3aS,4S,6S,7aS)-3a,5,5-trimethylhexahydro-4,6-methano-1,3,2-benzodioxaborol-2-yl]butyl} phenylalanine of formula (V). Compound (IV) is prepared by coupling (1R)-3-methyl-1-[(3aS,4S,6S,7aR)-3a,5,5-trimethyl-hexahydro-4,6-methano-1,3,2-benzodioxaborol-2-yl]butan-1-amine of formula (II) or its salt with N-(tert-butoxycarbonyl)-L -phenylalanine of formula (III) in a first solvent in the presence of a first coupling agent and a first base, wherein the coupling process does not comprise solvent exchange. Compound (V) is prepared by deprotecting compound (IV) using an alcoholic solution of an inorganic acid.
