N.[OH:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[CH:9]=[C:8]([C:13]([OH:15])=[O:14])[CH:7]=[CH:6]2.[Na].[Cl-].[NH4+]>C(O)C>[OH:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[CH2:9][CH:8]([C:13]([OH:15])=[O:14])[CH2:7][CH2:6]2Liquid ammonia (7 equi.) is condensed into a solution of 6-hydroxy-naphthalene-2-carboxylic acid (15) (1 equi) in ethanol (1.2 mL/mmole) at −78 C. Sodium (4.3 equi.) was added in 4 portions to the reaction mixture. Each portion gave blue color, but it disappeared quickly. The reaction mixture was stirred for 20 min, ammonium chloride (4.3 equi.) was added, it was stirred for another 1 h and anmmonia was distilled off by warming reaction pot to room temperature. The reaction mixture was quenched with water and 10% hydrochloric acid, extracted with ethyl acetate, washed with brine, dried over MgSO4, and concentrated in vacuo. Purification by recrystallization from acetonitrile gave 6-hydroxy-1,2,3,4-tetrahydro-naphthalene-2-carboxylic acid (29) as a white solid (73%).
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