[H-].[Na+].[CH3:3][O:4][CH:5]([C:14]1[CH:19]=[CH:18][C:17]([O:20][CH3:21])=[CH:16][CH:15]=1)[CH2:6][CH:7]=[CH:8][CH:9]=[CH:10][C:11](O)=[O:12].C(Cl)(=O)C([Cl:25])=O>C1C=CC=CC=1>[CH3:3][O:4][CH:5]([C:14]1[CH:19]=[CH:18][C:17]([O:20][CH3:21])=[CH:16][CH:15]=1)[CH2:6][CH:7]=[CH:8][CH:9]=[CH:10][C:11]([Cl:25])=[O:12]To a suspension of 60% NaH (0.059 g, 1.47 mmol) washed previously with dry pentane (2×5 mL) in dry benzene (5 mL) at 5° C. was added dropwise a solution of carboxylic acid 4 (0.30 g, 1.14 mmol) in dry benzene (5 mL) via cannula. After 20 min, oxalyl chloride (117 μL, 1.34 mmol) was added via microsyringe, and then the reaction mixture was allowed to warm to rt over 30 min. After stirring for an additional 1.5 h at rt, the mixture was filtered and the filtrate was concentrated under reduced pressure to give the desired acid chloride 5 in 93% yield as a red-orange oil. Without further purification, this crude product was used in the next step: 1H NMR (300 MHz, CDCl3) δ 7.40 (dd, J=15.3, 10.5 Hz, 1H), 7.20 (d, J=8.4 Hz, 2H), 6.90 (d, J=8.4 Hz, 2H), 6.30 (m, 2H), 5.98 (d, J=15.3 Hz, 1H), 4.18 (dd, J=7.5, 4.8 Hz, 1H), 3.82 (s, 3H ), 3.20 (s, 3H ), 2.61 (m, 1H), 2.48 (m, 1H).
Wird geladen…
