تفاعل #320783

معادلة التفاعل

sodium nitrite

7-amino-4-bromo-6-chloro-2,3-dihydro-2,2-dimethylbenzofuran

toluene

sulfuric acid

→

4-bromo-6-chloro-2,3-dihydro-2,2-dimethylbenzofuran

المردود 0.2%

المذيبات

ethanol

ظروف التفاعل

المعالجة

1. 1
   workup.ADDITIONis then added
2. 2
   أخرىThe ice bath is then removed
3. 3
   درجة الحرارةAfter this time the reaction mixture is warmed to 95° C.
4. 4
   workup.STIRRINGwhere it stirred for one hour
5. 5
   درجة الحرارةThe reaction mixture is then cooled
6. 6
   workup.ADDITIONpoured into 200 mL of water
7. 7
   استخلاصThe mixture is extracted with two 150 mL portions of diethyl ether
8. 8
   تجفيفThe combined extracts are dried with magnesium sulfate
9. 9
   ترشيحfiltered
10. 10
    تركيزThe filtrate is concentrated under reduced pressure to a residue
11. 11
    غسيلElution
12. 12
    تركيزconcentrated under reduced pressure

الإجراء التجريبي

A stirred solution of 5.1 grams (0.01 8 mole) of 7-amino-4-bromo-6-chloro-2,3-dihydro-2,2-dimethylbenzofuran and 25 mL of toluene in 100 mL of ethanol is cooled in an ice bath, and 2 mL (0.036 mole) of concentrated sulfuric acid is added slowly. Upon completion of addition, 2.0 grams (0.029 mole) of sodium nitrite is then added. The ice bath is then removed, and the reaction mixture is warmed to 75° C., where it is stirred for 30 minutes. After this time the reaction mixture is warmed to 95° C., where it stirred for one hour. The reaction mixture is then cooled and poured into 200 mL of water. The mixture is extracted with two 150 mL portions of diethyl ether. The combined extracts are dried with magnesium sulfate and filtered. The filtrate is concentrated under reduced pressure to a residue. The residue is subjected to column chromatography on silica gel. Elution is accomplished using petroleum ether. The product-containing fractions are combined and concentrated under reduced pressure, yielding 3.6 grams of 4-bromo-6-chloro-2,3-dihydro-2,2-dimethylbenzofuran. The NMR spectrum is consistent with the proposed structure.

المصدر