反应详情

To a stirred mixture of 1.15 g. (10 m mole) of maleamic acid and 1.40 ml. of triethylamine in 40 ml. of dry tetrahydrofuran, at 0° C., is added 1.57 ml. (12 m mole) of isobutyl chloroformate followed by three drops of N-methylmorpholine. Stirring is continued for a further 30 minutes at 0° C. To this mixed anhydride is then added a solution prepared by adding 2.40 g. (10 m mole) of 6-amino-2,2-dimethyl-3-(5-tetrazolyl)penam to a mixture of 15 ml. of water and 15 ml. of tetrahydrofuran and adjusting the pH to 7.5. The resulting mixture is then stirred for a further 1 hour at 0° C. At this point, the tetrahydrofuran is removed by evaporation in vacuo, and the residue is diluted with more water. The pH is adjusted to 8.0 with 6 N sodium hydroxide, and then the mixture is extracted with ethyl acetate. The extracts are discarded. The pH of the residual aqueous phase is adjusted to 2.0 with 4 N hydrochloric acid and then the product is extracted into ethyl acetate. The organic layer is dried and concentrated in vacuo to give 6-(3-[carbamoyl]-acrylamido)-2,2-dimethyl-3-(5-tetrazolyl)penam (1.03 g., 33% yield). The infrared spectrum (KBr disc) of the product shows absorption bands at 1818 cm-1 (β-lactam) and 1692 cm-1. The NMR spectrum (DMSO-d6) shows bands at 7.00 and 6.25 (quartet, 2H, J = 12 Hz, olefinic hydrogens), 5.80-5.48 ppm (multiplet, 2H, C-5 and C-6 hydrogens), 5.26 ppm (singlet, 1H, C-3 hydrogen), 1.65 ppm (singlet, 3H, C-2 methyl hydrogens) and 1.06 ppm (singlet, 3H, C-2 methyl hydrogens).

1. additionTo a stirred mixture of 1.15 g
2. customprepared
3. additionby adding 2.40 g
4. stirringThe resulting mixture is then stirred for a further 1 hour at 0° C
5. customAt this point, the tetrahydrofuran is removed by evaporation in vacuo
6. additionthe residue is diluted with more water
7. extractionthe mixture is extracted with ethyl acetate
8. extractionthe product is extracted into ethyl acetate
9. customThe organic layer is dried
10. concentrationconcentrated in vacuo