Reaktion #362831

Reaktionsgleichung

(S)-N-tert-butoxycarbonyltyrosine

sodium hydride

sodium hydride

1-tosyl-2-chloroethanol

1-tosyl-2-chloroethanol

→

(S)-N-tert-butoxycarbonyl-4-O-(2-chloroethyl)tyrosine

Ausbeute 79.0%

Lösungsmittel

water

water

DMF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeare placed in a three-necked flask under a nitrogen atmosphere
2. 2
   workup.STIRRINGhas been stirred for 2 days
3. 3
   workup.WAITThe same procedure is carried out after 24 h
4. 4
   workup.WAITthe stirring is continued for a further 24 h
5. 5
   Einengenthe reaction mixture is concentrated to dryness under reduced pressure
6. 6
   SonstigeThe residue which is obtained
7. 7
   Extraktionextracted with 3 times 100 ml of ethyl acetate
8. 8
   SonstigeThe aqueous phase is separated off
9. 9
   Extraktionthe product is extracted with 3 times 100 ml of ethyl acetate
10. 10
    Waschenwashed with 2 times 50 ml of water
11. 11
    Sonstigeseparated off
12. 12
    Trocknendried over magnesium sulphate
13. 13
    Filtrationfiltered
14. 14
    Einengenconcentrated to dryness under reduced pressure in order

Vorschrift

14 g of (S)-N-tert-butoxycarbonyltyrosine, dissolved in 140 ml of DMF, are placed in a three-necked flask under a nitrogen atmosphere. 4.8 g of 50% sodium hydride in oil are added slowly using a spatula. 16.87 g of 1-tosyl-2-chloroethanol are added after the mixture has been stirred for 2 h at room temperature. 2.4 g of 50% sodium hydride in oil, and a further 8.4 ml of 1-tosyl-2-chloroethanol, are added after the mixture has been stirred for 2 days. The same procedure is carried out after 24 h and the stirring is continued for a further 24 h. The reaction is stopped by adding 100 ml of distilled water, and the reaction mixture is concentrated to dryness under reduced pressure. The residue which is obtained is taken up in 100 ml of distilled water and then extracted with 3 times 100 ml of ethyl acetate. The aqueous phase is separated off after settling and acidified to pH3 with 50 ml of 1N HCl, and the product is extracted with 3 times 100 ml of ethyl acetate. The organic phases are combined, washed with 2 times 50 ml of water, separated off, dried over magnesium sulphate, filtered and then concentrated to dryness under reduced pressure in order to yield 13.51 g of (S)-N-tert-butoxycarbonyl-4-O-(2-chloroethyl)tyrosine in the form of a chestnut oil (Rf=0.5, toluene 70%/methanol 20%/diethylamine 10%), which is used as such in the following step.

Quelle