تفاعل #87954

معادلة التفاعل

N-Bromosuccinimide

methyl 2-(tert-butyldimethylsilyloxy)-6-methylbenzoate

Intermediate 13

methyl 2-(tert-butyldimethylsilyloxy)-6-methylbenzoate

→

methyl 2-bromomethyl-6-(tert-butyldimethylsilyloxy)benzoate

المردود 32.7%

المذيبات

carbon tetrachloride

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةheated to reflux
2. 2
   درجة الحرارةThe mixture was cooled
3. 3
   workup.WAITleft
4. 4
   ترشيحthen filtered through a 25 g silica cartridge
5. 5
   غسيلeluting with a mixture of ethyl acetate and pentane (20%)
6. 6
   أخرىThe eluent was evaporated to dryness
7. 7
   workup.DISSOLUTIONthe residue was redissolved in carbon tetrachloride (150 mL)
8. 8
   workup.ADDITIONN-bromosuccinimide (6.96 g) was added
9. 9
   درجة الحرارةThe mixture was heated
10. 10
    درجة الحرارةto reflux
11. 11
    workup.ADDITIONazo-bis-isobutyronitrile (0.1 g) was added
12. 12
    أخرىThe resultant mixture was illuminated with a 500 W tungsten filament lamp overnight
13. 13
    درجة الحرارةAfter cooling
14. 14
    ترشيحthe mixture was filtered
15. 15
    غسيلthe solid was washed with pentane
16. 16
    أخرىThe combined organic solutions were evaporated to dryness
17. 17
    أخرىthe residue was purified by chromatography on silica
18. 18
    غسيلeluting with a mixture of TBME and pentane with a gradient of 0-10%

الإجراء التجريبي

N-Bromosuccinimide (7.6 g) was added to a solution of methyl 2-(tert-butyldimethylsilyloxy)-6-methylbenzoate (Intermediate 13, 11.9 g) in carbon tetrachloride (150 mL) and the mixture was stirred and heated to reflux. Azo-bis-isobutyronitrile (0.1 g) was added and the mixture was illuminated with a 500 W tungsten filament lamp for 2 hours. The mixture was cooled and left to stand overnight then filtered through a 25 g silica cartridge eluting with a mixture of ethyl acetate and pentane (20%). The eluent was evaporated to dryness and the residue was redissolved in carbon tetrachloride (150 mL) and N-bromosuccinimide (6.96 g) was added. The mixture was heated to reflux and azo-bis-isobutyronitrile (0.1 g) was added. The resultant mixture was illuminated with a 500 W tungsten filament lamp overnight. After cooling, the mixture was filtered and the solid was washed with pentane. The combined organic solutions were evaporated to dryness and the residue was purified by chromatography on silica, eluting with a mixture of TBME and pentane with a gradient of 0-10% to give methyl 2-bromomethyl-6-(tert-butyldimethylsilyloxy)benzoate (4.99 g) as a yellow oil.

المصدر