Oxalyl chloride → (S)-2-(3,4-dichlorophenyl)pent-4-enoyl chloride
Reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([C@H:9]([CH2:13][CH:14]=[CH2:15])[C:10](O)=[O:11])[CH:5]=[CH:6][C:7]=1[Cl:8].C(Cl)(=O)C([Cl:19])=O>CN(C)C=O.ClCCl>[Cl:1][C:2]1[CH:3]=[C:4]([C@H:9]([CH2:13][CH:14]=[CH2:15])[C:10]([Cl:19])=[O:11])[CH:5]=[CH:6][C:7]=1[Cl:8]Participants
Procedure
Combine (S)-2-(3,4-dichlorophenyl)pent-4-enoic acid (6.55 g, 26.7 mmol), dichloromethane (10 mL), and dimethylformamide (2 drops). Add a solution of oxalyl chloride (16 mL, 2 M, 32 mmol) in dichloromethane. After 2 hours, evaporate in vacuo to give (S)-2-(3,4-dichlorophenyl)pent-4-enoyl chloride. Combine with toluene (20 mL) and slowly add, with vigorous stirring, to a cooled (ice bath) aqueous solution of methylamine (4 mL, 40%) while maintaining the temperature of the reaction mixture at less than 10° C. When the addition is complete add toluene (40 mL). After 1 hour, partition the reaction mixture between water and dichloromethane. Separate the layers, extract the organic layer with a saturated aqueous sodium bicarbonate solution, dry over MgSO4, filter, and evaporate in vacuo to give a residue. Chromatograph the residue on silica gel eluting sequentially with 10% ethyl acetate/hexane, 20% ethyl acetate/hexane, and 30% ethyl acetate/hexane to give (S)-2-(3,4-dichlorophenyl)pent-4-enoic acid, N-methyl amide: Rf=0.50 (silica gel, 50% ethyl acetate/hexane).
Workup
- customevaporate in vacuo
Sources & evidence
- ORD record
- ord-ae4445c62127407f84e2318825ce2fd5
- Source dataset
- uspto-grants-2001_11
- Patent number
- US06316445B1
Reaction notes
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