Reaction #1994222

Reaction equation

DCM

5

tert-Butyl 2-(4-((tert-Butyldimethylsilyloxy)methyl)-2-(hydroxymethyl)benzoyl)hydrazinecarboxylate

4-nitrophenyl chloroformate

pyridine

→

6

Yield 97.0%

tert-Butyl 2-(4-((tert-Butyldimethylsilyloxy)methyl)-2-(((4-nitrophenoxy)carbonyloxy)methyl)benzoyl)hydrazinecarboxylate

Yield 97.0%

Solvents

THF

THF

Conditions

Workup

1. 1
   Temperatureto warm up
2. 2
   workup.STIRRINGStirring
3. 3
   workup.WAITwas continued at room temperature for 16 h
4. 4
   WashThe mixture was washed with 1M HCl (3×60 mL) and brine (1×50 mL)
5. 5
   Extractionthe aqueous layers were re-extracted with DCM
6. 6
   DryingThe combined organic phases were dried over MgSO4
7. 7
   Otherthe volatiles were removed in vacuo

Procedure

To a solution of 4-nitrophenyl chloroformate (1.10 g, 5.48 mmol) in 40 mL of anhydrous THF was added pyridine (390 μL, 5.48 mmol) at 0° C. After stirring for 15 min, a solution of 5 (1.50 g, 3.65 mmol) in 15 mL of anhydrous THF was added dropwise within 10 min, and the mixture was allowed to warm up. Stirring was continued at room temperature for 16 h after which 50 mL DCM was added. The mixture was washed with 1M HCl (3×60 mL) and brine (1×50 mL), and the aqueous layers were re-extracted with DCM. The combined organic phases were dried over MgSO4 and the volatiles were removed in vacuo. Flash chromatography of the crude product (1:2 EtOAc-hexane) afforded 6 (97%) as a colorless solid: 1H-NMR (400 MHz, CDCl3): δ 0.11 (s, 6H), 0.94 (s, 9H), 1.49 (s, 9H), 4.79 (s, 2H), 5.58 (s, 2H), 6.71 (br s, 1H), 7.37-7.42 (m, 3H), 7.54 (s, 1H), 7.61 (d, J=8.1 Hz, 1H), 7.96 (br s, 1H), 8.23-8.29 (m, 2H); 13C-NMR (100 MHz, CDCl3): δ −5.1, 18.5, 26.0, 28.3, 64.3, 68.5, 82.3, 121.9, 125.4, 126.5, 127.4, 128.3, 131.4, 133.6, 145.5, 145.7, 152.5, 155.5, 155.6, 168.0; MS (TOF) m/z=598.2 (M+Na+, 100).

Source