反应详情

An improvement in the process for preparing 3-(4-pyridinyl)-2-cyclohexen-1-one oxime by heating ethyl 5-oxo-2-[(4-pyridinyl)carbonyl]hexanoate under aqueous acidic conditions to produce 1-(4-pyridinyl)-hexan-1,5-dione, heating said hexan-1,5-dione with a basic condensing agent to produce 3-(4-pyridinyl)-2-cyclohexen-1-one, and converting said cyclohexen-1-one to its oxime, said improvement being a one pot sequence consisting of first heating ethyl 5-oxo-2-[(4-pyridinyl)carbonyl]hexanoate with excess aqueous sulfuric acid, neutralizing the excess acid, shaking the resulting warm mixture well with isopropyl alcohol to extract the 3-(4-pyridinyl)-2-cyclohexen-1-one, draining off the heavier warm aqueous layer, adding hydroxylamine hydrochloride to the isopropyl alcohol solution of 3-(4-pyridinyl)-2-cyclohexen-1-one, stirring the mixture at reflux, basifying the mixture and evaporating the reaction mixture to dryness, and isolating the 3-(4-pyridinyl)-2-cyclohexen-1-one oxime from the residue.