Reaction #1121762

Reaction equation

NaH

6

4-Bromopyrrole-2-carboxaldehyde

p-toluenesulfonyl chloride

→

crystals

Yield 68.6%

4-Bromo-2-formyl-N-p-tosylpyrrole

Yield 68.6%

Solvents

THF

Conditions

Workup

1. 1
   workup.WAITAfter 16 h
2. 2
   OtherThe reaction mixture was quenched
3. 3
   workup.ADDITIONby adding aqueous NH4Cl
4. 4
   workup.ADDITIONEthyl acetate was added
5. 5
   Otherthe organic layer was separated
6. 6
   WashThe organic layer was washed with water, brine
7. 7
   Dryingdried (Na2SO4)
8. 8
   ConcentrationConcentration
9. 9
   Otherfollowed by crystallization (ethyl acetate/hexanes)

Procedure

Following a reported procedure,18 a stirred suspension of NaH (865 mg, 36.0 mmol) in THF (200 mL) was treated with 6 (5.22 g, 30.0 mmol) at room temperature. When the evolution of gas had ceased, the mixture was stirred for 1 h before treating with p-toluenesulfonyl chloride (6.30 g, 33.0 mmol). After 16 h, the conversion was complete as monitored by TLC. The reaction mixture was quenched by adding aqueous NH4Cl. Ethyl acetate was added and the organic layer was separated. The organic layer was washed with water, brine and dried (Na2SO4). Concentration followed by crystallization (ethyl acetate/hexanes) afforded pale yellow crystals (6.75 g, 68%): mp 83-85° C.; 1H NMR δ 2.43 (s, 3H), 7.09 (d, J=2.0 Hz, 1H), 7.35 (d, J=8.3 Hz, 2H), 7.57 (d, J=2.0 Hz, 1H), 7.81 (d, J=8.3 Hz, 2H), 9.94 (s, 1H); 13C NMR δ 22.0, 101.8, 125.4, 127.8, 127.9, 130.6, 133.5, 134.7, 146.7, 178.5. Anal. Calcd or C12H10BrNO3S: C, 43.92; H, 3.07; N, 4.27; S, 9.77. Found: C, 43.92; H, 3.02; N, 4.26; S, 9.84.

Source