[OH:1][CH2:2][CH2:3][C:4]1[CH:5]=[C:6]([C:14]([O:16][CH3:17])=[O:15])[C:7]2[C:12]([CH:13]=1)=[CH:11][CH:10]=[CH:9][CH:8]=2.I[CH3:19].[H-].[Na+]>C1COCC1>[CH3:19][O:1][CH2:2][CH2:3][C:4]1[CH:5]=[C:6]([C:14]([O:16][CH3:17])=[O:15])[C:7]2[C:12]([CH:13]=1)=[CH:11][CH:10]=[CH:9][CH:8]=2Methyl 3-(2-hydroxyethyl)-1-naphthalenecarboxylate (1 eq.) from the previous step and iodomethane (19 eq.) were taken up in THF (0.3 M). To this solution was then added sodium hydride (60% w/w dispersion in oil, 1 eq.) and the resulting suspension was stirred at RT in darkness for 18 h. The volatiles were then removed in vacuo and the resulting residue partitioned between ether and 1 N aq. HCl. The aqueous layer was separated and back-extracted with ether. The combined organic extracts were then washed further with 1 N aq. NaOH, water and brine. This was then dried over Na2SO4, filtered and the filtrate concentrated in vacuo to afford a yellow oil. Purification of the crude product thus obtained by way of flash chromatography (SiO2, 19:1 (v/v) Hex:EtOAc→1:1 (v/v) EtOAc:Hex) afforded the title compound as a pale yellow oil.
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