[OH:1][C:2]1[CH:11]=[C:10]([OH:12])[CH:9]=[CH:8][C:3]=1[C:4]([O:6][CH3:7])=[O:5].[CH:13]1(O)[CH2:18][CH2:17][CH2:16][CH2:15][CH2:14]1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N(C(OC(C)C)=O)=NC(OC(C)C)=O>O1CCCC1>[CH:13]1([O:12][C:10]2[CH:9]=[CH:8][C:3]([C:4]([O:6][CH3:7])=[O:5])=[C:2]([OH:1])[CH:11]=2)[CH2:18][CH2:17][CH2:16][CH2:15][CH2:14]1A 3.00 g portion of methyl 2,4-dihydroxybenzoate was dissolved in 30 ml of tetrahydrofuran, and 2 ml of cyclohexanol, 9.00 g of triphenylphosphine and 7.38 ml of diisopropyl azodicarboxylate were added, followed by stirring for 12 hours at room temperature. After completion of the reaction, the solvent was evaporated, the resulting residue was mixed with hexane-ethyl acetate, and insoluble matter was removed by filtration. Solvent of the filtrate was evaporated and the resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=12:1-2:1) to give 1.70 g of methyl 4-cyclohexyloxy-2-hydroxybenzoate. Nuclear magnetic resonance spectrum (DMSO-d6, TMS internal standard) δ: 1.10-2.10 (10H, m), 3.86 (3H, s), 4.40-4.48 (1H, m), 6.43-6.58 (2H, m), 7.63-7.75 (1H, m), 10.71 (1H, s)
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