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自烷氧基乙酸乙酯的乙氧草酰化,继以热裂去羰化反应,合成了一系列烷氧基丙二酸二乙酯(Ⅵ,R=n-C_3H_7,n-C_4H_9,iso-C_4H_9,iso-C_5H_(11)和C_6H_5CH_2);进一步烷基化,得到烷氧基烷基丙二酸二乙酯(Ⅶ,R′=CH_3,C_2H_5,n-C_3H_7和n-C_4H-9)。烷氧基烷基丙二酸二乙酯(Ⅶ)与脲、硫脲和与胍的缩合的容易程度相差颇巨。除苯甲氧基乙基丙二酸二乙酯曾与脲缩合生成相应的5,5-二取代巴比酸(I,Y=O)外,其他的各烷氧基烷基丙二酸二乙酯(Ⅶ)均未能与脲顺利地发生缩合。各烷氧基烷基丙二酸二乙酯(Ⅶ)与硫脲的缩合效果较佳,但其中仍有若干未能得到所期望的2-硫代巴比酸(I,Y=S)。两个系列的烷氧基烷基丙二酸二乙酯(Ⅶ,R=n-C_3H_7和C_6H_5CH_2;R′=CH_3,C_2H_5,n-C_3H_7,和n-C_4H_9)与胍的缩合非常顺利,生成相应的5,5-二取代-2-亚氨基巴此酸(I,Y=NH)。5-苯甲氧基-5-烷基-2-亚氨基巴比酸还进行了氢解,得到相应的5-羟基-5-烷基-2-亚氰基巴比酸(I,R=H,R′=烷基,Y=NH)。
A series of diethyl alkoxymalonate esters (VI, R = n-C_3H_7, n-C_4H_9, iso) were synthesized from the oxaloylation of ethyloxyacetate followed by thermal cleavage (VII), R’= CH_3, C_2H_5, n-C_3H_7 and n-C_4H-9) were obtained by further alkylation to give the alkoxyalkylmalonate . The ease of condensation of diethyl Alkoxyalkylmalonate (VII) with urea, thiourea and guanidine is quite different. In addition to the ethyl ester of phenyl methoxyethylmalonate which has been condensed with urea to give the corresponding 5,5-disubstituted barbituric acid (I, Y = O), other alkoxyalkylmalonic acid di Ethyl ester (Ⅶ) failed to condensation with urea smoothly. The condensation of diethyl Alkoxyalkylmalonate (VII) with thiourea is better, but several of these still fail to give the desired 2-thiobarbituric acid (I, Y = S). The condensation of two series of alkoxyalkylmalonate (VII, R = n-C_3H_7 and C_6H_5CH_2; R ’= CH_3, C_2H_5, n-C_3H_7, and n-C_4H_9) with guanidine proceeded very well to form The corresponding 5,5-disubstituted-2-iminobarbyl acid (I, Y = NH). The 5-benzyloxy-5-alkyl-2-imino-dibromic acid is also subjected to a hydrogenolysis to give the corresponding 5-hydroxy-5-alkyl-2-cyanobabalic acid (I, R = H, R ’= alkyl, Y = NH).