반응 #1159005

반응 방정식

4-methoxybenzyl 7β-phenylacetamido-3-methylenecepham-4-carboxylate

4-methoxybenzyl 7β-amino-3-methylenecepham-4-carboxylate p-toluenesulfonic acid

PCl5

K2HPO4

H3PO4

→

4-Methoxybenzyl 7β-amino-3-methylenecepham-4-carboxylate

용매

dichloromethane

pyridine

methanol

반응 조건

후처리

1. 1
   workup.STIRRINGstirring
2. 2
   workup.STIRRINGthe mixture is stirred 90 minutes at −15° C.
3. 3
   기타60 minutes
4. 4
   기타at 0° C.
5. 5
   기타at 25° C
6. 6
   workup.WAITto stand 30 minutes
7. 7
   workup.STIRRINGunder stirring at 25° C.
8. 8
   기타the organic phase is separated
9. 9
   추출the organic one is extracted twice with dichloromethane
10. 10
    건조the collected organic phases are dried over sodium sulfate
11. 11
    농축concentrated under reduced pressure
12. 12
    workup.DISSOLUTIONThe obtained oily residue is dissolved in 70 ml of ethyl acetate
13. 13
    온도the solution is cooled to 0° C.
14. 14
    workup.ADDITIONtreated first with a solution of 3.15 g of p-toluene sulfonic acid monohydrate in 70 ml of ethyl acetate
15. 15
    workup.WAITAfter standing overnight at 4° C.
16. 16
    여과the precipitate is filtered
17. 17
    기타to give

실험 절차

To a previously cooled (−15° C.) solution of 5 g of 4-methoxybenzyl 7β-phenylacetamido-3-methylenecepham-4-carboxylate in 200 ml of anhydrous dichloromethane, 8.9 ml of anhydrous pyridine and, subsequently, 7.3 g of PCl5 are added under stirring, and stirring is continued for 1 hour at −15° C. The reaction mixture is cooled to −30° C., 55.4 ml of absolute methanol are added thereinto, the mixture is stirred 90 minutes at −15° C. then 60 minutes at 0° C. and finally 60 minuts at 25° C. To the resulting mixture, 200 ml of a 0.5 M solution of K2HPO4 are added, the the pH is adjusted to bout 2 by addition of 5% H3PO4. The mixture is let to stand 30 minutes under stirring at 25° C., then the organic phase is separated, the organic one is extracted twice with dichloromethane and the collected organic phases are dried over sodium sulfate and concentrated under reduced pressure. The obtained oily residue is dissolved in 70 ml of ethyl acetate, the solution is cooled to 0° C. and treated first with a solution of 3.15 g of p-toluene sulfonic acid monohydrate in 70 ml of ethyl acetate, then with 70 ml of diethyl ether. After standing overnight at 4° C., the precipitate is filtered to give 3.92 g of practically pure (thin layer chromatography, eluent ethyl acetate/n-hexane 7/3, Rf=0.20) 4-methoxybenzyl 7β-amino-3-methylenecepham-4-carboxylate p-toluenesulfonic acid addition salt.

출처