2-Bromopyridine → HCID 22843545, compound

Participants

Reaction Steps

To 2-bromopyridine (3.16 g) in 20 ml of dry tetrahydrofuran cooled to -78° C. under argon was added slowly 11.2 ml of n-butyl lithium in tetrahydrofuran (2M). The solution was stirred for 5 minutes and then 2.1 g of N-t-butoxycarbonyl-L-leucinal in 10 ml of tetrahydrofuran was added. The mixture was stirred for 35 minutes, then quenched with 10 ml of saturated sodium sulfate solution, warmed to room temperature and poured into 50 ml of water. The mixture was extracted with ethyl acetate. The extract was dried (Na2SO4) and the solvent removed under vacuum. The residue was chromatographed over silica gel with ethyl acetatheexane (3:7) as eluent and then ethyl acetate-hexane (1:1) as eluent to give 0.62 g of (S) 2-tert-butoxycarbonyl-amino-4-methyl(R,S)1-(2-pyridinyl)pentan-1-ol as a yellow oil; [α]D26 -21°±3° (C, 0.329, dichloromethane). A4.12 sample of the preceding compound in a mixture of 15 ml of dichloromethane and 5 ml of acetic anhydride was stirred at room temperature for 22 hours. The mixture was concentrated under vacuum. The residue was dissolved in dichloromethane and the solution washed with saturated agneous sodium carbonate, dried (Na2SO4) and the solvent removed. The residue was chromatographed over silica gel with 30% ethyl acetate in hexane to give 1.55 g of (S) 2-tert-butoxycarbonylamino-4-methyl-(S)1-(2-pyridinyl)pentan-1-ol, 0-acetate as crystals, mp 83°-84° C.; [α]D26 -62°±1° (C. 1.01, dichloromethane) and (S) 2-tert-butoxycarbonylamino-4-methyl-(R)1-(2-pyridinyl)pentan-1-ol, 0-acetate as an amber oil; [α]D26 +3°±1° (C, 1.-66, methanol).

Provenance & Evidence