Dedicated to Professor Emeritus Volker Jäger, Institut für Organische Chemie, Universität Stuttgart, on the occasion of his 70th birthday.

Abstract

A series of tetrahydropyrazolo[1,5-c]pyrimidine-2,7(1H,3H)-diones 3a–h as the first representatives of the so far unexplored saturated heterocyclic system have been synthesized, formally in 12 steps from methyl acrylate (4). The synthesis comprises a four-step preparation of methyl N-Cbz-5-alkylamino-3-oxopentanoates 9a–c, their three-step transformation into 5-{2-[(alkyl)(benzyloxycarbonyl)amino]ethyl}pyrazolidin-3-ones 12a–c, three-step selective alkylation of the amidic N-2 to give 2-alkyl-5-{2-[(alkyl)(benzyloxycarbonyl)amino]ethyl}pyrazolidin-3-ones 16b–h, followed by hydrogenolytic Cbz-deprotection and subsequent cyclization of the intermediate 1,4-diamine with CDI to furnish the title compounds 3. Most of the synthetic steps were performed as a one-pot transformation.

A series of tetrahydropyrazolo[1,5-c]pyrimidine-2,7(1H,3H)-diones 3a–h as the first representatives of the so far unexplored saturated heterocyclic system have been synthesized, formally in 12 steps from methyl acrylate (4). The synthesis comprises a four-step preparation of methyl N-Cbz-5-alkylamino-3-oxopentanoates 9a–c, their three-step transformation into 5-{2-[(alkyl)(benzyloxycarbonyl)amino]ethyl}pyrazolidin-3-ones 12a–c, three-step selective alkylation of the amidic N-2 to give 2-alkyl-5-{2-[(alkyl)(benzyloxycarbonyl)amino]ethyl}pyrazolidin-3-ones 16b–h, followed by hydrogenolytic Cbz-deprotection and subsequent cyclization of the intermediate 1,4-diamine with CDI to furnish the title compounds 3. Most of the synthetic steps were performed as a one-pot transformation.

中文翻译：

---

四氢吡唑并[1,5-c]嘧啶-2,7（1H，3H）-二酮的合成

在他70岁生日之际，献给斯图加特大学有机化学研究所名誉教授VolkerJäger。

抽象

一系列四氢吡唑并[1,5- c ]嘧啶-2,7 （1 H，3 H）-二酮3a - h作为迄今未开发的饱和杂环系统的第一个代表已合成，从甲基开始以十二个步骤正式形成丙烯酸酯（4）。合成过程包括N -Cbz-5-烷基氨基-3-氧代戊酸甲酯9a-c的四步制备，将其三步转化为5- {2-[（烷基）（苄氧基羰基）氨基]乙基}吡唑啉丁-3 -a 12a – c，对酰胺基N-2进行三步选择性烷基化，得到2-烷基-5- {2-[（（烷基）（苄氧羰基）氨基]乙基}吡唑啉丁-3-ones 16b– h，然后进行Cbz脱氢氢解，然后将中间体1,4-二胺与CDI环合，得到标题化合物3。大多数合成步骤都是一锅法进行的。

一系列四氢吡唑并[1,5- c ]嘧啶-2,7 （1 H，3 H）-二酮3a - h作为迄今未开发的饱和杂环系统的第一个代表已合成，从甲基开始以十二个步骤正式形成丙烯酸酯（4）。合成过程包括N -Cbz-5-烷基氨基-3-氧代戊酸甲酯9a-c的四步制备，将其三步转化为5- {2-[（烷基）（苄氧基羰基）氨基]乙基}吡唑啉丁-3 -a 12a – c，对酰胺基N-2进行三步选择性烷基化，得到2-烷基-5- {2-[（（烷基）（苄氧羰基）氨基]乙基}吡唑啉丁-3-ones 16b– h，然后进行Cbz脱氢氢解，然后将中间体1,4-二胺与CDI环合，得到标题化合物3。大多数合成步骤都是一锅法进行的。