作者:Erin Campbell、Bradley J Newhouse、Jon Bordner、Edward F Kleinman
DOI:10.1016/s0040-4020(01)87220-3
日期:1993.8
catalyst yielded the epimeric spiro ketals 4a and 4b along with a minor amount of the pyranoid ketal 2. Contrary to a literature report, treatment of KBBL in 2% methanolic HCl gave the rearranged methyl ester 3 rather than ketal 2. Ketals 2, 4a, and 4b are potentially useful intermediates for the further elaboration of the ascorbic acid nucleus of KBBL because the ketone and one hydroxyl of the butyrolactone
用Amberlyst®15作为催化剂在干燥的甲醇中处理免疫刺激剂KBBL(1a),产生了差向异构的螺缩酮4a和4b以及少量的吡喃类酮缩酮2。与文献报道相反,在2%的HCl溶液中处理KBBL产生了重排的甲酯3而不是缩酮2。缩酮2,图4A,和图4B它们是KBBL抗坏血酸核进一步加工的潜在有用中间体,因为丁内酯核(来自抗坏血酸)的酮和一个羟基同时被保护为内部缩酮。获得了这些化合物的X射线结构,有助于我们了解免疫刺激剂KBBL家族的结构。