Hydrochloric Acid → 2-Methylphenylacetylene

Participants

Reaction Conditions

Reaction Steps

Potassium hydroxide (10 g, 1.8 mol) added in 4 portions to a stirred solution of trimethyl-(2-methylphenyl)ethynylsilane (114.0 g, 0.61 mol) in methanol (400 ml) at 0° C. The mixture was stirred at 0° C. until the reaction was complete (by tlc 1:1 ethyl acetate:hexane). The mixture was neutralised by the addition of 10% hydrochloric acid and the product was extracted into dichloromethane (2×150 ml). The combined extracts were dried (MgSO4) and evaporated in vacuo. The residual oil was purified by short path distillation (Kugelrohr) to give 1-ethynyl-2-methylbenzene (52.03 g) as a clear oil. B.pt. 45° C./12 mBar. 250 MHz 1H-NMR (CDCl3) δ (ppm): 2.35 (s, 3H) (ArCH3), 3.2 (s, 1H)(CH), 7.0-7.2 (m, 3H) (3×ArH), 7.4 (m, 1H) (ArH); GC purity 98%, GC retention time 7.94 min.

Provenance & Evidence