Abstract Nine new alkyl-oximes were obtained from 2-methyl-4(5)-nitro-1H-imidazole with 2-bromo-1-phenylethanone derivatives in a first step, as well as hydroxylamine hydrochloride and alkyl halide derivatives in a second step. Spectroscopic characterization mainly by NMR (nuclear magnetic resonance) allowed us to assign the 4-nitro and 5-nitro position isomers in the ethanone derivatives (3a-3c), it also allowed us to assign the geometric isomers (E/Z) in oximes (4a-4c) and alkyl-oximes (5a-5i). The HRMS (high-resolution mass spectrometry) allowed us to define the molecular ion (M + 1) with its isotopic pattern, complementing the unequivocal characterization of the nine compounds. Experimental and calculated FT-IR data (Fourier transform infrared spectroscopy) indicates that the symmetric and asymmetric bands of the nitro group do not change substantially when the ethanones become oximes. The position of the nitro group in the compounds, the optimized structures of minimum energy, as well as the geometric organization of the substituents in the isomers, have been interpreted by PBE0-D3/6–311++G(d,p) calculations and the results coincided with the spectroscopic data found experimentally.

中文翻译：

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新烷基肟衍生物合成中 (E/Z)-异构体的光谱和计算分析

摘要 第一步从 2-甲基-4(5)-硝基-1H-咪唑与 2-溴-1-苯基乙酮衍生物合成了 9 种新的烷基肟，第二步合成了盐酸羟胺和卤代烷衍生物。 . 主要通过 NMR（核磁共振）进行的光谱表征使我们能够确定乙酮衍生物 (3a-3c) 中的 4-硝基和 5-硝基位置异构体，它还允许我们确定肟中的几何异构体 (E/Z) (4a-4c) 和烷基肟 (5a-5i)。HRMS（高分辨率质谱）使我们能够定义分子离子 (M + 1) 及其同位素模式，补充了九种化合物的明确表征。实验和计算出的 FT-IR 数据（傅里叶变换红外光谱）表明，当乙酮变成肟时，硝基的对称和不对称带没有发生实质性变化。PBE0-D3/6–311++G(d,p)计算解释了化合物中硝基的位置、最小能量的优化结构以及异构体中取代基的几何结构结果与实验发现的光谱数据一致。