Benzoic acid, 4-(allyloxy)-3,5-dimethyl- → 4-Allyloxy-3,5-dimethyl-benzoic acid chloride

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反応手順

To a solution of 4-allyloxy-3,5-dimethyl-benzoic acid (5.26 g, 25.5 mmol) in CHCl3 (75 mL), thionylchloride (7.5 mL, 103 mmol) is added at rt. The mixture is refluxed for 2 h before the solvent is evaporated to give crude 4-allyloxy-3,5-dimethyl-benzoic acid chloride as a brownish oil. To a solution of the acid chloride in DCM (50 mL) hydrazine (75 mL of a 1 M solution in THF) in DCM (250 mL) is added at 0° C. The mixture is stirred at rt for 15 h before it is diluted with diethyl ether and extracted with 1 N aq. HCl (75 mL, then 5×50 mL). The combined aq. extracts are basified by adding 33% aq. KOH solution and extracted with DCM (5×50 mL). The combined DCM extracts are dried over Na2SO4, filtered and evaporated to give 4-allyloxy-3,5-dimethyl-benzoic acid hydrazide (5.39 g) as a white solid; LC-MS: tR=0.71 min, [M+1]+=221.20, 1H NMR (D6-DMSO): δ 2.22 (s, 6H), 4.28-4.37 (m, 2H), 4.39 (s, 2H), 5.19-5.28 (m, 1H), 5.36-5.47 (m, 1H), 6.00-6.15 (m, 1H), 7.49 (s, 2H), 9.55 (s, 1H).

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