Sulfuric Acid → 3,4-dihydro-1-hydroxy-5-methyl-1-(trifluoromethyl)-2(1H)-naphthalenone oxime

Participants

Reaction Conditions

Reaction Steps

Cold concentrated H2SO4 (12 ml, 98% w/v H2SO4 in water) was added to a stirred suspension of 1,1,1-trifluoro-5-(2-methylphenyl)-2,3-pentanedione 3-oxime (11.9 g, 45.9 mmol) in toluene (16 mL) at 0° C. The reaction mixture and allowed to warm to room temperature (25° C.) and then stirred for 30 min. Ice was added to the reaction mixture. The resulting mixture was extracted with diethyl ether (2x). The ether extract was washed successively with water and a saturated aqueous solution of NaHCO3, dried (MgSO4) and concentrated under reduced pressure to give the title compound (10.4 g, 87% yield). This product was used for the reaction described in the following example. A small sample was triturated with hexane to give-off white crystals; mp 154°-156° C.; nmr (CDCl3) δ 2.3 (s, 3H), 2.9 (m, 4H), 7.2 (m, 2H), 7.6 (m, 1H); ir (CHCl3) 3570, 3480, 1170 cm-1 ; uvλmax (MeOH) 273 nm (ε570), 266 (590).

Provenance & Evidence