【摘要】 <正> 吡喃酮是许多天然产物的结构单元,我们曾由4-异丁酰基庚二酸在过量醋酸酐及乙酰氯存在下回流得到7-氧代-8,8-二甲基-△⁹-六氢香豆素.本文由二氰乙基-β-二酮进行酮解水解反应得到4-酰基庚二酸1_a-c。 在过量醋酸酐、乙酰氯存在下由1_a、1_c为底物进行反应没有得到双环的香豆素衍生物.其产物和单纯以乙酐为缩合剂时的产物2_a、2_c相同,产率分别为68％、63％。2_c可在硫酸铁催化更多还原

【Abstract】 5-(2’ -Carboxyethyl)-6-methyl-3,4-dihydropyrone(2a) and 5-(2’ -carboxyethyl)-6-isobutyl-3,4-dihydropyrone (2c) were prepared from 4-acetyl heptanedioic acid (1a) and 4-iso-valeryl hyptanedioic acid (1c) in the presence of acetic anhydride with yields of 63%, 68% respectively. When 1c was refluxed with ferric sulfate hydrate as the catalyst product 2c also formed in 63% yield. 2a,c or 5-(2’-carboxyethyl)-6-isopropyl-3, 4-dihydropyrone (2b) reacted with ethyl alcohol to afford 4-acylheptanedioic acid diethyl ester (3a-c) in the presence of hydrochlo-ride. Treatment of 2a-c with ammonia water gave 5-(2’ -carboxyethyl)-6-alkyl-3, 4-dihydro pyridone (4a-c) in 55%-72% yields.更多还原