تفاعل #2446149

معادلة التفاعل

6-bromo-3,4-dihydroquinoxalin-2(1H)-one

formaldehyde

water

acetic acid

NaBH3CN

→

6-bromo-4-methyl-3,4-dihydroquinoxalin-2(1H)-one

المردود 94.0%

المذيبات

methanol

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةrefluxed for 1 h
2. 2
   workup.STIRRINGstirring
3. 3
   workup.WAITwas continued for 2.5 h at room temperature
4. 4
   أخرىThen methanol was removed under vacuum
5. 5
   workup.ADDITIONTo the remaining mixture water was added
6. 6
   استخلاصextracted several times with ethyl acetate
7. 7
   غسيلThe combined organic layers were washed with brine
8. 8
   تجفيفdried over MgSO4
9. 9
   أخرىevaporated

الإجراء التجريبي

To a solution of 6-bromo-3,4-dihydroquinoxalin-2(1H)-one (370 mg, 1.63 mmol) in 10 ml methanol was added a solution of 37% formaldehyde in water (59 mg, 1.95 mmol) and acetic acid (196 mg, 3.26 mmol). The mixture was stirred at room temperature for 2 h, then refluxed for 1 h. After addition of NaBH3CN (307 mg, 4.89 mmol) stirring was continued for 2.5 h at room temperature. Then methanol was removed under vacuum. To the remaining mixture water was added. Then the solution was basified to pH 8-9 with an aqueous solution of sodium hydrogen carbonate and extracted several times with ethyl acetate. The combined organic layers were washed with brine, dried over MgSO4 and evaporated, affording 6-bromo-4-methyl-3,4-dihydroquinoxalin-2(1H)-one (369 mg, 1.53 mmol, 94%) as off-white solid.

المصدر