[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[CH:9]=[C:8](C(O)=O)[CH:7]=[CH:6]2.C([N:18]([CH2:21]C)CC)C.C1(P(N=[N+]=[N-])(C2C=CC=CC=2)=[O:30])C=CC=CC=1.[C:40]([OH:44])([CH3:43])([CH3:42])[CH3:41]>>[C:40]([O:44][C:21](=[O:30])[NH:18][C:8]1[CH:7]=[CH:6][C:5]2[C:10](=[CH:11][CH:12]=[C:3]([O:2][CH3:1])[CH:4]=2)[CH:9]=1)([CH3:43])([CH3:42])[CH3:41]A mixture of 6-methoxy-naphthalene-2-carboxylic acid (10.00 g, 49.5 mmol), triethylamine (6.9 mL, 49.5 mmol) and diphenylphosphoryl azide (10.7 mL, 49.6 mmol) in 200 mL of anhydrous tert-butyl alcohol was refluxed under nitrogen for 5.5 h. The tert-butyl alcohol was removed under reduced pressure. The residue was dissolved in methylene chloride and extracted with 1 N HCl, 1 N NaOH, dried (MgSO4) and the solvent removed under reduced pressure to give (6-Methoxy-naphthalen-2-yl)-carbamic acid tert-butyl ester (11.14 g, 82%) as an off-white solid, mp 124-127° C.
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