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 (2×). 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, 2 H), 7.6 (m, 1H); ir (CHCl3) 3570, 3480, 1170 cm-1 ; uvλmax (MeOH) 273 nm (ε 570), 266 (590).

Provenance & Evidence