α-羧基烯酮环二硫代缩醛化学(Ⅷ)——以叔丁醇钾为碱合成脂肪族α-羰基烯酮环二硫代缩醛类化合物

The Chemistry of α-Oxo Ketene Cyclic Dithioacetals(Ⅷ) ——Studies on the Synthesis of Aliphatic α-Oxo Ketene Cyclic Dithioacetals with Potassium tert-Butoxide as Base

前文曾报道了以六甲基二硅氨基锂(LHMDS)为碱合成标题化合物的方法。进一步的实验表明,以叔丁醇钾为碱用于芳香族α-碳基烯酮环二硫代缩醛类化合物的合成效果较好。为此,本文以叔丁醇钾为碱合成了1_(a—j)等10个标题化合物,其中1_(d—j)为新化合物。实验表明,碱的浓度、反应所用溶剂对产物的产率有明显影响。叔丁醇钾的浓度以0.4 mol/L左右为宜,采用苯和DMF混合溶剂并以脂环酮为底物时产率较好。

Ten title compounds were synthesized starting from aliphatic ketones with potassium tert-butoxide as the base. The yields are strongly dependent on the concentration of the base and solvents used. Lower concentration is favorable to raising the yields. When the concentration of the base was 0. 4 mol/L, the best yield was obtained. The solvent mixed with benzene and DMF favored the increase of the yields of products with cyclic ketones as the substrates. For the IR spectra, the carbonyl absorptions of compounds 1 are normally lower than 1647 cm-1. This might result from the strong conjugation in compound 1. Among the products, 1d-1j are new compounds.