Phosphorus pentachloride → HCID 18537043, compound
Reaction equation
[Cl:1][C:2]1[CH:10]=[C:9]([O:11][CH3:12])[C:8]([O:13][CH3:14])=[CH:7][C:3]=1[C:4](O)=[O:5].P(Cl)(Cl)(Cl)(Cl)[Cl:16]>>[Cl:1][C:2]1[CH:10]=[C:9]([O:11][CH3:12])[C:8]([O:13][CH3:14])=[CH:7][C:3]=1[C:4]([Cl:16])=[O:5]Participants
3
Conditions
- Temperature
- 120 °C
Procedure
2-Chloro-4,5-dimethoxybenzoic acid (0.5 g, 2.3 mmol) and PCl5 (0.54 g, 2.6 mmol) were placed in a round bottomed flask fitted with a reflux condenser. The mixture was heated in an oil bath at 120° C. for 70 min. The mixture was allowed to cool and the formed phosphorus oxychloride was removed under vacuum to give 0.52 g (96%) of 2-chloro-4,5-dimethoxybenzoyl chloride as a solid. 2-Chloro-4,5-dimethoxybenzoyl chloride (0.52 g, 2.2 mmol) was treated in a manner similar to that for Example 32 step (a) to give 2-bromo-1-(2-chloro-4,5-dimethoxyphenyl)ethan-1-one. The dry solid (0.65 g, 2.2 mmol) was dissolved in acetone (25 ml). To this solution 5-(methoxycarbonyl)-2-(methylthio)-thiophene-3-thiocarboxamide (0.55 g, 2.2 mmol) was added and heated at reflux for 5 h. At this point the solid that precipitated was filtered off and washed with acetone and dried under vacuum to give 0.53 g (54%) of methyl 4-[4-(2-chloro-4,5-dimethoxyphenyl)(1,3-thiazol-2-yl)]-5-methylthiothiophene-2-carboxylate. 1H-NMR (DMSO-d6; 300 MHz) δ2.73 (s, 3H), 3.83 (s, 3H), 3.84 (s, 3H), 3.85 (s, 3H), 7.13 (s, 1H), 7.69 (s, 1H), 8.13 (s, 1H), 8.17 (s, 1H).