2-Benzyl, 2-phenyl, 2- (3-methoxyphenyl) and 2-(3-trifluoromethylphenyl) octahydropyrrolo[3,4-c]pyrrole (9a, 9b, 9c, and 9d, respectively) were prepared in five steps from 1-benzylpyrrole-3,4-dicarboxylic acid (2). 2-Methyloctahydropyrrolo [3,4-c]pyrrole (9′a) was prepared analogously in six steps from 1-methylpyrrole-3,4-dicarboxylic acid (3). Diborane reduction of 1-benzyl-N-methyl-1H-pyrrole-3,4-dicarboximide (7′a) and 1, N-dibenzyl-1H-pyrrole-3,4-dicarboximide (7a) gave 5-benzyl-2-methyl and 2, 5-dibenzyl-1,2,3,5-tetrahydropyrrolo [3,4-c]pyrrole (19′ and 19, respectively); the first reported members of the 1,2,3,5-tetrahydropyrrolo[3,4-c]pyrrole ring system. A detailed study of the carbon-13 nmr shifts permitted a complete assignment for all compounds. Mono and disubstituted products produce a systematic effect on the shifts for the bicyclic ring systems which can be readily interpreted in terms of substituent chemical shifts. The effect of protonation at nitrogen is also shown to produce a series of well defined chemical shifts for the octahydropyrrolo [3,4-c] pyrrole ring system.

中文翻译：

---

2-苄基，2-甲基，2-芳基氢吡咯并[3,4- c ]吡咯和1,2,3,5-四氢吡咯并[3,4- c ]吡咯环体系的合成及碳-13 NMR研究

从以下五个步骤制备2-苄基，2-苯基，2-（3-甲氧基苯基）和2-（3-三氟甲基苯基）八氢吡咯并[3,4- c ]吡咯（分别为9a，9b，9c和9d） 1-苄基吡咯-3，4-二羧酸（2）。由六个步骤，由1-甲基吡咯-3，4-二羧酸（3）类似地制备2-甲基八氢吡咯并[3，4- c ]吡咯（9′a）。1-苄基-N-甲基-1H-吡咯-3,4-二甲酰亚胺（7'a）和1，N-二苄基-1H-吡咯-3,4-二甲酰亚胺（7a）的乙硼烷还原）得到5-苄基-2-甲基和2，5-二苄基-1,2,3,5-四氢吡咯并[3,4- c ]吡咯（分别为19 '和19）；首次报道了1,2,3,5-四氢吡咯并[3,4- c ]吡咯环系统的成员。对碳13 nmr位移的详细研究允许对所有化合物进行完整分配。单取代和双取代的产物对双环体系的位移产生系统的影响，这可以根据取代基的化学位移容易地解释。氮原子上的质子化作用也显示出对八氢吡咯并[3,4- c ]吡咯环系统产生一系列定义明确的化学位移。