反応 #55420

反応方程式

7β-amino-7α-methoxy-3-[1-(2-t-butoxycarbonylethyl)tetrazol-5-ylthiomethyl]-3-cephem-4-carboxylic acid t-butyl ester

N,N-diethylaniline

→

7β-D-Mandelamido-7α-methoxy-3-[1-(2-carboxyethyl)tetrazol-5-ylthiomethyl]-3-cephem-4-carboxylic acid

溶媒

methylene chloride

methylene chloride

反応条件

後処理

1. 1
   workup.STIRRINGstirred for an additional 30 minutes
2. 2
   洗浄The solution is washed with 50 ml
3. 3
   乾燥of cold 5% aqueous sodium bicarbonate, dried
4. 4
   その他evaporated to dryness
5. 5
   workup.DISSOLUTIONThe residue is dissolved in a mixture of 10 ml
6. 6
   workup.STIRRINGof m-dmethoxybenzene and stirred at ambient temperature for 2 hours
7. 7
   その他The excess trifluoroacetic acid is evaporated under vacuum
8. 8
   その他the residue is partitioned between 50 ml
9. 9
   その他The organic phase is separated
10. 10
    workup.STIRRINGThe aqueous phase is stirred at pH 9.3-9.5 for 30 minutes
11. 11
    抽出extracted with 50 ml
12. 12
    抽出The aqueous layer is extracted with three 50 ml
13. 13
    乾燥portions of ethyl acetate and the combined extracts are dried
14. 14
    その他evaporated to a small volume
15. 15
    workup.ADDITIONPetroleum ether is added dropwise
16. 16
    その他to precipitate the title compound which
17. 17
    ろ過is collected by filtration
18. 18
    その他dried

実験手順

A solution of 1.06 g. (2 mmol.) of 7β-amino-7α-methoxy-3-[1-(2-t-butoxycarbonylethyl)tetrazol-5-ylthiomethyl]-3-cephem-4-carboxylic acid t-butyl ester and 0.30 g. (2 mmol.) of N,N-diethylaniline in 100 ml. of dry methylene chloride is stirred at 0°-5° while 0.56 g. (2 mmol.) of D-O-dichloroacetylmandeloyl chloride in 10 ml. of methylene chloride is added dropwise over 10 minutes. The mixture is stirred in the cold for 30 minutes then warmed to room temperature and stirred for an additional 30 minutes. The solution is washed with 50 ml. of cold dilute hydrochloric acid and 50 ml. of cold 5% aqueous sodium bicarbonate, dried and evaporated to dryness. The residue is dissolved in a mixture of 10 ml. of trifluoroacetic acid and 2 ml. of m-dmethoxybenzene and stirred at ambient temperature for 2 hours. The excess trifluoroacetic acid is evaporated under vacuum and the residue is partitioned between 50 ml. of ether and 50 ml. of water and adjusted to pH 9.3-9.5 with 5% aqueous sodium carbonate. The organic phase is separated and discarded. The aqueous phase is stirred at pH 9.3-9.5 for 30 minutes, extracted with 50 ml. of ethyl acetate which is discarded, layered with fresh ethyl acetate and adjusted to pH 1.5 with dilute hydrochloric acid. The aqueous layer is extracted with three 50 ml. portions of ethyl acetate and the combined extracts are dried and evaporated to a small volume. Petroleum ether is added dropwise to precipitate the title compound which is collected by filtration and dried.

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