[NH2:1][CH2:2][C:3]1[CH:7]=[CH:6][S:5][C:4]=1[CH2:8][C:9]([OH:11])=[O:10].C(N(CC)CC)C.[C:19]([O:23][C:24](N=[N+]=[N-])=[O:25])([CH3:22])([CH3:21])[CH3:20]>CC(C)=O>[C:19]([O:23][C:24]([NH:1][CH2:2][C:3]1[CH:7]=[CH:6][S:5][C:4]=1[CH2:8][C:9]([OH:11])=[O:10])=[O:25])([CH3:22])([CH3:21])[CH3:20]A mixture of 3-aminomethyl-2-thienylacetic acid 8 (3.1 g, 18 m. moles) and triethylamine (8 g. 80 m moles) in 50% aqueous acetone (80 ml) was added dropwise t-butoxycarbonyl azide (5.7 g, 40 m moles) over a period of 20 mins. at 0° C. with vigorous stirring. The reaction mixture was stirred overnight at room temperature and concentrated under reduced pressure. The concentrate was washed with ether (2×20 ml), adjusted to pH 2 with conc. HCl and extracted with ethyl acetate (2×50 ml). The ethyl acetate extracts were washed with saturated aqueous sodium chloride, dried over MgSO4, treated with charcoal and evaporated under reduced pressure. The residue was triturated with n-hexane and crystallized from n-hexane and benzene to give 4.5 g (92%) of colorless needles 9, melting at 62°-63° C.
Loading…
