28315-93-7

83-56-7

28315-93-7

The general procedure for the synthesis of 5-hydroxy-1-tetralone from 1,5-dihydroxynaphthalene is as follows: Example 1-1 Method A Preparation of [5-(biphenyl-4-sulfonylamino)-5,6,7,8-tetrahydronaphthalen-1-yloxy]-acetic acid; Synthesis of 5-hydroxy-3,4-dihydro-2H-naphthalen-1-one To a mixed solution of isopropanol (150 mL) and aqueous sodium hydroxide (40 mL) containing 1,5-dihydroxynaphthalene (25.0 g, 156 mmol) was added 10% palladium carbon catalyst (3.9 g) at room temperature. The reaction mixture was transferred to a Parr autoclave (Parr Instrument Company) and reacted at 80 °C for 20 h under 100 psi hydrogen pressure. Upon completion of the reaction, the mixture was cooled to room temperature, filtered through a diatomaceous earth pad (diatomaceous earth filter from World Minerals Inc.) and the filter cake was washed with isopropanol (200 mL). The combined filtrates were treated with activated carbon at 50 °C for 1 h and subsequently filtered through a Celite pad (diatomaceous earth filter). Isopropanol was removed by distillation under reduced pressure and the pH was adjusted to about 2 by slowly adding concentrated hydrochloric acid to the remaining solution, at which point a solid precipitated. The solid product was collected, washed with water (100 mL x 2), and then dried under high vacuum at 50 °C to afford 5-hydroxy-3,4-dihydro-2H-naphthalen-1-one (15.0 g, 60% yield) as a dark brown solid, which can be used in subsequent steps without further purification. Mass spectrometry analysis: calculated value (C10H10O2) 162, measured value (M+H)+ 163.