Reaction of 2,4-Dibromomenthone with Zinc and Ethanol. Investigation of the Thujone of Guha and Nath

Abstract

Clemmensen reduction of the hydroxytetralone (XIII, 0.20 g.) led to a quantitative yield of the tetralol (VII, R = H) as brown crystals, m.p. 71-75°. Recrystallization from dilute methanol afforded colorless needles, m.p. 78°( mixed m.p ).When the relatively impure specimen of the methoxy acid (X) was used in the above reaction, a different result was obtained. X (0.70 g.), m.p. 114-115°, was treated with 48% hydrobromic acid (7 cc.) in glacial acetic acid (3.5 cc.), as described above. Along with the tetralone (XIII, 0.11 g., 20%), an acid (XIV, 0.13 g., 19%) was obtained as brown needles, m.p. 110-113°. Reaystallization from wrater gave colorless elongated needles, m.p. 116-117°.