반응 #96217

반응 방정식

Benzyl 6-benzyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate

ethanethiol

potassium carbonate

→

benzyl 6-benzyl-3-ethylthio-7-oxo-1-azabicyclo[3.2.0]heptane-2-carboxylate

용매

dimethylformamide

반응 조건

후처리

1. 1
   workup.DISTILLATIONthe solvent was then distilled off under high vacuum
2. 2
   기타The residue was partitioned between ethyl acetate and brine
3. 3
   건조the ethyl acetate solution was dried over sodium sulphate
4. 4
   농축concentrated
5. 5
   기타The residue was carefully chromatographed on a column of silica gel 60 (<230 mesh)
6. 6
   세척eluting with ethyl acetate/60°-80° petroleum ether 3:7

실험 절차

Benzyl 6-benzyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate (138) (0.420 g) was dissolved in dry dimethylformamide (5 ml) and treated with ethanethiol (0.12 ml) and potassium carbonate (0.087 g). It was stirred at ambient temperature for 1 hour and the solvent was then distilled off under high vacuum. The residue was partitioned between ethyl acetate and brine, and the ethyl acetate solution was dried over sodium sulphate and concentrated. The residue was carefully chromatographed on a column of silica gel 60 (<230 mesh) eluting with ethyl acetate/60°-80° petroleum ether 3:7 to give three diastereoisomers of benzyl 6-benzyl-3-ethylthio-7-oxo-1-azabicyclo[3.2.0]heptane-2-carboxylate as gums. The first compound in increasing order of polarity was the 2α, 3α-isomer (139) (0.054 g); νmax (CHCl3) 2950, 1765 and 1745 sh; τ(CDCl3) 2.6-2.9 (10H, m, phenyls), 4.86(2H, s, OCH2), 5.59(1H, d J 5 Hz, C2-H), 6.1-6.5(2H, m, C3-H and C5-H), 6.6-7.2(3H, m, C6-H, C8-H2), 7.50(2H, q J7 Hz, SCH2), 7.55 (1H, dt J14 and 7 Hz, C4-H), 8.41(1H, dt J14 and 7 Hz, C4-H) and 8.84(3H, t J7 Hz, CH3); (M+ at m/e 395.1554. C23H25NO3S requires 395.1553). Next was the 2α, 3β-isomer (98 ) (0.260 g); νmax (CHCl3) 2960, 1765 and 1750 sh cm-1 ; τ(CDCl3) 2.6-2.9 (10H m, phenyls), 4.87 (2H, s, OCH2), 5.26(1H, d, J7 Hz, C2-H), 6.10(1H, td, J51/2& 21/2 Hz, C5-H), 6.52(1H, td J9 and 7 Hz, C3-H), 6.7-7.2(3H, m, C6-H, C8-H2), 7.47(2H, q, J7 Hz, SCH2), 7.89 (2H, dd J9 and 51/2 Hz, C4-H2) and 8.85(3H, t J7 Hz, CH3); (M+ at m/e 395.1553. C23H25NO3S requires 395.1553). Lastly was obtained the 2β, 3α-isomer (140) (0.112 g); νmax (CHCl3) 2960, 1770 and 1745 cm-1 ; τ(CDCl3) 2.6-2.9(10H, m, phenyls), 4.82(2H, s, OCH2), 5.94(1H, d J8 Hz, C2-H), 6.2-7.2(5H, m, C3-H, C5-H, C6-H and C8-H2), 7.51(2H, d J7 Hz, SCH2), 7.83(1H, dt J12 and 6 Hz, C4-H), 8.10(1H, td J12 and 9 Hz, C4-H) and 8.86(3H, t J7 Hz, CH3); (M+ at m/e 394.1560. C23H25NO3S requires 395.1553).

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