Dimethylformamide → 3-Thiophenecarboxaldehyde, 2-ethyl- (9CI)
Reaction equation
Br[C:2]1[CH:6]=[CH:5][S:4][C:3]=1[CH2:7][CH3:8].[Li]CCCC.CN([CH:17]=[O:18])C>C(OCC)C>[CH2:7]([C:3]1[S:4][CH:5]=[CH:6][C:2]=1[CH:17]=[O:18])[CH3:8]Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- -78 °C
Procedure
A solution of 3-bromo-2-ethylthiophene, A7, (8.9 g, 0.0465 mol) in 50 mL of diethyl ether was cooled to -78° C., and a solution of n-BuLi (29.0 mL, 1.6M) in hexanes was added dropwise. When the addition was complete, the reaction was stirred at -78° C. for 5 min. Then DMF (5.1 g, 0.070 mol) was cannulated into the reaction mixture which was allowed to warm to ambient temperature and was stirred overnight. The reaction was quenched with water and extracted twice with diethyl ether. The organic extracts were combined, washed with twice with water and then brine and dried (MgSO4). The solution was filtered and concentrated to provide an oil which was purified on flash silica gel with 97.5:2.5 hexanes:diethyl ether to give 1.66 g (25%) of 2-ethylthiophene-3-carboxaldehyde, B7. The 1H NMR in CDCl3 supported the desired product structure. ##STR55##
Workup
- additionWhen the addition
- temperatureto warm to ambient temperature
- stirringwas stirred overnight
- customThe reaction was quenched with water
- extractionextracted twice with diethyl ether
- washwashed with twice with water
- dry with materialbrine and dried (MgSO4)
- filtrationThe solution was filtered
- concentrationconcentrated
- customto provide an oil which
- customwas purified on flash silica gel with 97.5:2.5 hexanes
Sources & evidence
- ORD record
- ord-2229459f21de4acc83888b1ca5918ff2
- Source dataset
- uspto-grants-1998_05
- Patent number
- US05750720
Reaction notes
Loading…