2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → HCID 71599372, compound

Participants

Reaction Steps

Several batches were prepared, using additional 77 g of 4-bromo-1-[(3-chloro-2-methylphenyl)methyl]-2-methyl-6-(4-morpholinyl)-1H-benzimidazole (177.11 mmol), either by the method above or by using 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane as the quenching agent. After standard work up the batches were combined with the above material and purified first by RP-HPLC (Luna C18(2), 5 u, 101×250 mm, 55:45 300 mM Aqueous ammonium trifluoroacetate (pH 2.8):acetonitrile), followed by purification on chiral phase (Chiralpak AD 101×250 mm, 20 u, 80:20 Heptane/EtOH plus 2% HCO2H and 1% Isopropylamine) and recrystallization from EtOAc to give [1-[(3-chloro-2-methylphenyl)methyl]-2-methyl-6-(4-morpholinyl)-1H-benzimidazol-4-yl]boronic acid (18.03 g, 45.17 mmol, 23.4% yield) as a beige powder.

Provenance & Evidence