Ethyl Acetate → 6,7-Dihydroxy-4-oxo-4H-1-benzopyran-3-carbonyl chloride
Reaktionsgleichung
[CH3:1]/[C:2](/[O:8][Si](C)(C)C)=N\[Si](C)(C)C.O[C:14]1C=C[CH:21]=[C:20]2[C:15]=1[C:16](=[O:28])[C:17]([C:25]([Cl:27])=[O:26])=[C:18](O)[O:19]2.C(OCC)(=[O:31])C>>[OH:31][C:1]1[CH:14]=[C:15]2[C:20](=[CH:21][C:2]=1[OH:8])[O:19][CH:18]=[C:17]([C:25]([Cl:27])=[O:26])[C:16]2=[O:28]Komponenten
4
Reaktionsbedingungen
- Temperatur
- 0 °C
Versuchsvorschrift
7β-[D-2-Amino-2-(4-hydroxyphenyl)acetamido]-7α-methoxy-3-(1-methyl-5-tetrazolyl)thiomethyl-3-cephem-4-carboxylic acid trifluoroacetic acid salt (150 mg) was subjected to suspension into ethyl acetate (7.5 ml) and was added thereto with stirring at 0° C. N,O-bis(trimethylsilyl)acetamide (417 μl). To the resulting mixture was added with stirring at 0° C. dihydroxychromon-3-carbonyl chloride (58 mg) which was obtained in the preceding Item (a). There was added once more N,O-bis(trimethylsilyl)acetamide (417 μl), and the whole was stirred at 0° C. for three hours. After addition of ethyl acetate (150 ml) to the reaction solution, the mixture was washed successively with 30 ml each of 0.5 N hydrochloric acid, distilled water (twice) and a saturated saline. The organic layer recovered therefrom was dried over magnesium sulfate, and the solvent was distilled off. The residue thus obtained was dissolved in acetone (30 ml) and allowed to stand at room temperature overnight. After removal by filtration of a small quantity of an insoluble matter separated out, the solvent was distilled off. Ethyl ether was added to the residue to cause trituration of the latter. There was thus obtained through filtration the desired substance (105 mg).