تفاعل #11385

معادلة التفاعل

2-acetamido-4-fluoro-2,4-dideoxy-D-glucopyranose

acetic anhydride

→

2-acetamido-1,3,6-tri-O-acetyl-2,4-dideoxy-4-fluoro-D-glucopyranose

المذيبات

pyridine

ظروف التفاعل

المعالجة

1. 1
   أخرىclose spots
2. 2
   workup.STIRRINGStirring
3. 3
   workup.WAITcontinued for another 15 hours
4. 4
   أخرىSolvent was then removed by evaporation in vacuo
5. 5
   أخرىthen dried in vacuo
6. 6
   workup.ADDITIONpoured in CH2Cl2/acetone (8:1)
7. 7
   غسيلThe column was eluted with 500 ml of CH2Cl2/acetone (8:1)
8. 8
   غسيلeluted immediately
9. 9
   أخرىwith virtually no separation
10. 10
    أخرىThe CH2Cl2/CH3OH flush
11. 11
    أخرىproduced a trailing spot
12. 12
    أخرىAll were evaporated
13. 13
    أخرىdried in vacuo

الإجراء التجريبي

A solution of 2-acetamido-4-fluoro-2,4-dideoxy-D-glucopyranose (1.35 g, 6.048 mmol) in a mixture of pyridine (50 ml) and acetic anhydride (25 ml, 27 g, 264 mmol) was stirred at room temperature for 24 hours at which time no starting material but two close spots appeared by TLC. Stirring continued for another 15 hours. Solvent was then removed by evaporation in vacuo; the residue was now co-evaporated with toluene (4×50 ml) then dried in vacuo. This material was now adsorbed on 5 g of silica gel then placed on a silica gel column (45 g, 20×360 mm) poured in CH2Cl2/acetone (8:1). The column was eluted with 500 ml of CH2Cl2/acetone (8:1) followed by 500 ml of CH2Cl2/CH3OH (7:3). The product and trailing spots eluted immediately, with virtually no separation. The CH2Cl2/CH3OH flush produced a trailing spot. All were evaporated and dried in vacuo.

المصدر