Unusual amino acids are of crucial importance to the synthesis of bioactive peptides and new chemical entities. Innovative methodology is always needed for the preparation of enantiomerically pure amino acids that does not rely on tedious resolution procedures. The proline-derived ligands (R)- and (S)-N-(2-benzoyl-4-chlorophenyl)-1-(3,4-dichlorobenzyl)pyrrolidine-2-carboxamide are outstanding, versatile, and recyclable reagents for the synthesis of tailor-made α- and β-amino acids. Here we report initial studies of the scale-up synthesis of the HCl salt of these reagents on the 100 g scale. The results demonstrate an increased efficiency and environmental friendliness of the bench-scale procedure and provides a firm foundation for the manufacture on multikilogram and larger scales.

中文翻译：

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按比例放大合成（R）-和（S）-N-（2-苄基-4-氯苯基）-1-（3,4-二氯苄基）吡咯烷-2-羧酰胺盐酸盐，一种通用的制备裁缝试剂对映体纯净形式的α-和β-氨基酸

异常的氨基酸对于生物活性肽和新化学实体的合成至关重要。制备不依赖乏味拆分程序的对映体纯氨基酸始终需要创新的方法。脯氨酸衍生的配体（R）-和（S）-N-（2-苯甲酰基-4-氯苯基）-1-（3,4-二氯苄基）吡咯烷-2-羧酰胺是杰出的，用途广泛且可回收的试剂，用于合成定制的α-和β-氨基酸。在这里，我们报告了这些试剂的HCl盐按100 g规模放大合成的初步研究。结果证明了台式方法的效率提高和环境友好性，并为多千克和更大规模的生产提供了坚实的基础。