[Cl-].[OH:2][C@H:3]([CH3:15])[CH2:4][CH2:5][C:6]1[CH:11]=[C:10]([O:12][CH3:13])[CH:9]=[CH:8][C:7]=1[NH3+:14].[N:16](OCCC(C)C)=O.O>ClCCl.C([O-])(=O)C.C([N+](CCCC)(CCCC)CCCC)CCC>[CH3:13][O:12][C:10]1[CH:11]=[C:6]2[C:7](=[CH:8][CH:9]=1)[NH:14][N:16]=[C:5]2[CH2:4][C@H:3]([OH:2])[CH3:15]To a stirred suspension of the product from step C (2.66 g, 11.5 mmol) in dichloromethane (150 mL) at ambient temperature was added isoamyl nitrite (2.47 mL, 18.4 mmol, 1.6 equiv.). After 30 minutes tetrabutylammonium acetate (5.54 g, 18.4 mmol, 1.6 eq) was added and the mixture was stirred for 2 hours. Water was added to the mixture and the organic layer was separated and washed with 2 N NaOH and water. After drying and evaporation the crude product was purified by column chromatography (gradient of 20% to 40% ethyl acetate in hexane) to give an oil (1.58 g) that crystallized from ethyl acetate/hexane (1:1) to afford a solid (1.30 g, 55%): mp 89-91° C.; LC/MS (+APCI) m/z 207 (M+H).
Loading…
