The process development to the manufacturing route to (2S)-7-(4,4‘-bipiperidin-1-ylcarbonyl)-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid hydrochloride (SB-214857-A, lotrafiban) is described. The starting point is the previously reported intermediate (2RS)-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid methyl ester. The first stage is a lipase-catalysed resolution of the racemic ester to (2S)-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid and subsequent iodination using a pyridine iodine monochloride complex to give (2S)-2,3,4,5-tetrahydro-7-iodo-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid. The unreacted (R)-enantiomer of the starting ester is recovered and recycled to the racemate by treatment with sodium methoxide. The next stage describes the palladium-catalysed aminocarbonylation of the aryl iodide with 4,4‘-pyridylpiperidine to give (2S)-2,3,4,5-tetrahydro-4-methyl-3-oxo-7-4-(4-pyridinyl)-1-piperidinylcarbonyl-1H-1,4-benzodiazepine-2-acetic acid dihydrate. The third stage is the hydrogenation of the pyridine subunit over palladium on charcoal to obtain the zwitterionic (2S)-7-(4,4‘-bipiperidin-1-ylcarbonyl)-2,3,4,5-tetrahydro-4-methyl-3-oxo-1H-1,4-benzodiazepine-2-acetic acid hexahydrate. The final stage is the formation of the hydrochloride salt to afford the drug substance.