Ethanol → 5-Heptynoic acid, 7-hydroxy-

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Reaction Steps

By following the procedure of A. I. Rachlin, et al., cited above, 6-chloro-2-hexyn-1-ol is prepared by condensing propargyl alcohol tetrahydropyran-2-yl ether and the dihaloalkane of formula VIII, 1-bromo-3-chloropropane, to give 1-[(tetrahydropyran-2-yl)oxy]-6-chloro-2-hexyne, which is then converted to the desired compound followed by hydrolysis in the presence of sulfuric acid. The 6-chloro-2-hexyn-1-ol (280 g) is dissolved in ethanol (2.8 l) then water (560 ml) and potassium cyanide (290 g) is added and the mixture stirred and refluxed for 20 hr. Potassium hydroxide (768 g) and water (500 ml) are added and the stirred mixture kept at reflux for an additional 20 hr. Methanol is evaporated and the water phase is acidified with concentrated HCl and extracted with ether for 2 days in a continuous liquid-liquid extractor. The ether extract is dried (Na2SO4) and concentrated to give the title compound, nmr (CDCl3) δ 4.22 (m, 2H), 7.41 (broad, 2H).

Provenance & Evidence