Synthesis and Rotational Isomerism of 1-Substituted Methyl (<i>S</i>)-[5-(2-Nitrophenyl)-1<i>H</i>-pyrazole-4-carbonyl]alaninates
作者:Luka Šenica、Karmen Stopar、Miha Friedrich、Uroš Grošelj、Janez Plavec、Marta Počkaj、Črtomir Podlipnik、Bogdan Štefane、Jurij Svete
DOI:10.1021/acs.joc.5b02467
日期:2016.1.4
Seven title compounds 12a–g and the (S)-prolinate analogue 13 were prepared in five steps from 2-nitrobenzoic acid (7). Reduction of the nitro group followed by derivatization of the so formed anilines 14 gave the N-alkyl-(15a–c), N-acyl-(16a,b and 19), and N-vinyl derivative 20. NMR spectra of (S)-alanine and (S)-proline derived compounds 12, 13, 14–16, 19, and 20 exhibited two sets of signals corresponding
从2-硝基苯甲酸(7)分五个步骤制备了七个标题化合物12a - g和(S)-脯氨酸盐类似物13。还原硝基基团,然后将如此形成的苯胺14衍生化,得到N-烷基-(15a - c),N-酰基-(16a,b和19)和N-乙烯基衍生物20。NMR谱(小号) -丙氨酸和(小号) -脯氨酸衍生的化合物12,13,14 - 16,19,和20显示出两套对应于对构象非对映体的信号。旋转的自由能垒ΔG ‡ 298 = 82–86 kJ mol –1通过1 H NMR测定12a,12d,12f和12g并通过DFT计算进行评估。