Revisitation of the PCl5-chlorination reaction of α-amino acids: Spectroscopic and DFT insights, and synthesis of the L-proline-derived 2,5-diketopiperazine
作者:Marco Bortoluzzi、Fabio Marchetti、Maria Grazia Murrali、Guido Pampaloni
DOI:10.1016/j.ica.2014.10.033
日期:2015.3
conditions, both in the solid state and in solution. The 1:2 molar reaction of PCl5 with L-proline selectively afforded the salt 2, showing better inertness than the homologous 1. The slow degradation reaction of 2 may represent a strategy for the clean synthesis of the L-proline-derived 2,5-diketopiperazine, which was recovered in ca. 60% yield from a dichloromethane solution stirred at room temperature
摘要通过光谱学和DFT研究阐明了α-氨基酸与PCl5的传统氯化反应。因此,可以从中高收率地获得1和[RCH(NH3)C(O)Cl] [Cl](R = H,3; R = CH3,4; R = CH2Ph,5; R = CH2CHMe2,6)。等摩尔量的PCl5和L-脯氨酸,甘氨酸,L-丙氨酸,L-苯丙氨酸和L-亮氨酸。结果表明,化合物3–6在室温和氮气气氛下稳定,而化合物1在相同条件下无论在固态还是在溶液中都迅速降解。PCl5与L-脯氨酸的1:2摩尔反应选择性地提供了盐2,显示出比同系物1更好的惰性。2的缓慢降解反应可能代表了干净合成L-脯氨酸衍生的2,5的策略。 -diketopiperazine,约于20年回收。在室温下搅拌数天,从二氯甲烷溶液中收率60%,然后用氮气吹扫以除去释放的HCl。通过元素分析和IR光谱对化合物1-6进行表征,对于可溶性1和2进行化合物NMR表征。此外,通过DF