Dimethylformamide → 1,3-Benzothiazole-2-carbaldehyde
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
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- -78 °C
Procedure
A solution of freshly distilled (b.p. 82° C., 2 torr) benzothiazole (10 g, 0.074 mole) in 250 ml tetrahydrofuran was cooled 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-butyllithium, 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 extracts 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. 1H--NMR(CDCl3)ppm (delta): 7.54 (m, 2H), 7.97 (m, 1H), 8.21 (m, 1H), 10.1 (s, 1H).
Workup
- stirringstirring
- waitcontinued for 25 minutes
- stirringthe reaction mixture stirred for an hour
- temperatureto warm to room temperature
- customthe solvent evaporated in vacuo
- extractionThe aqueous residue was extracted with 5×100 ml ethyl acetate
- dry with materialthe extracts dried (MgSO4)
- concentrationconcentrated to a small volume
- customchromatographed on a silica gel column
- washeluting with 96:4 chloroform/ethyl acetate
Sources & evidence
- ORD record
- ord-89bac9bae588406298cfa81b71b03bc1
- Source dataset
- uspto-grants-1989_05
- Patent number
- US04826833
Reaction notes
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