تفاعل #67932

معادلة التفاعل

I2

ethyl 2-bromoisobutyrate

pyridine

Benzyl carbazate

→

2-(N′-benzyloxycarbonyl-hydrazino)-2-methyl-propionic acid ethyl ester

المذيبات

—

hexanes

ethyl acetate

DMF

ظروف التفاعل

المعالجة

1. 1
   أخرىFrom two separate
2. 2
   workup.ADDITIONaddition funnels
3. 3
   درجة الحرارةHeating
4. 4
   أخرىthe reaction to completion
5. 5
   درجة الحرارةto cool
6. 6
   workup.ADDITIONpoured onto ice water
7. 7
   استخلاصThe aqueous mixture was extracted with ethyl ether
8. 8
   أخرىthe solvent was removed in vacuo

الإجراء التجريبي

Benzyl carbazate (25 g, 0.15 mol) was dissolved in 50 mL of DMF in a round bottom flask. The solution was heated to 95-100° C. From two separate addition funnels, ethyl 2-bromoisobutyrate (58.5 g, 0.3 mol) and pyridine (29.7 g, 0.375 mol, 30 mL) were added drop-wise separately and simultaneously over 30-120 minutes. Heating was continued if necessary to propel the reaction to completion. The reaction was monitored by TLC (30% ethyl acetate in hexanes, I2 visualization). The mixture was allowed to cool, and then poured onto ice water. The aqueous mixture was extracted with ethyl ether, and the solvent was removed in vacuo. 2-(N′-benzyloxycarbonyl-hydrazino)-2-methyl-propionic acid ethyl ester was isolated, optionally after silica gel chromatography. 1H NMR (300 MHz, CDCl3) δ (ppm): 7.36 (br s, 5H), 6.6 (br s, 1H), 5.15 (br s, 2H), 4.2 (q, 2H), 1.3 (s, 6H), 1.25 (t, 3H). 1H NMR analysis alone is insufficient to ascertain the extent of the reaction.

المصدر