Dimethylformamide → 1,3-Benzothiazole-2-carbaldehyde

HRID 2050777Notes

Reaction equation

HRID 2050777 reaction equation
[S:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[CH:2]1.C([Li])CCC.CN(C)[CH:17]=[O:18]>O1CCCC1>[S:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[C:2]1[CH:17]=[O:18]

Participants

5

Reactant 3

HCID 6228DimethylformamideHCID 7222BenzothiazoleHCID 178418339Butyllithium

Product 1

HCID 2416081,3-Benzothiazole-2-carbaldehydeYield 69.6%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

A solution of freshly distilled (b.p. 82° C., 2 torr) benzothiazole (10 g, 0.074 mole) in 250 ml tetrahydrofuran was colloed under nitrogen to -78° C. and stirred at this temperature for 15 minutes. To this was added dropwise over 15 minutes 29.6 ml (0.074 mole) 2,5M n-butyl-lithium, stirring continued for 25 minutes, and 8.6 ml (0.111 mole) dimethylformamide was added and the reaction mixture stirred for an hour. The mixture was allowed to warm to room temperature, 200 g ice was added and the solvent evaporated in vacuo. The aqueous residue was extracted with 5×100 ml ethyl acetate, the extractes dried (MgSO4), concentrated to a small volume and chromatographed on a silica gel column, eluting with 96:4 chloroform/ethyl acetate to yield 8.4 g of the desired aldehyde, m.p. 74.5-75° C. 1 -H--NMR(CDCl3)ppm (delta): 7.54 (m, 2H), 7.97 (m, 1H), 8.21 (m, 1H), 10.1 (s,1H.

Workup

  1. customwas colloed under nitrogen to -78° C.
  2. stirringstirring
  3. waitcontinued for 25 minutes
  4. stirringthe reaction mixture stirred for an hour
  5. customthe solvent evaporated in vacuo
  6. extractionThe aqueous residue was extracted with 5×100 ml ethyl acetate
  7. dry with materialthe extractes dried (MgSO4)
  8. concentrationconcentrated to a small volume
  9. customchromatographed on a silica gel column
  10. washeluting with 96:4 chloroform/ethyl acetate

Sources & evidence

ORD record
ord-2d1fb55bceb243f295db785abb00c2e8
Source dataset
uspto-grants-1991_05
Patent number
US05015473

Reaction notes

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