Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA.
Chemistry. 2012 Feb 27;18(9):2632-8. doi: 10.1002/chem.201103143. Epub 2012 Feb 13.
Open chain Cbz-L-aa(1)-L-Pro-Bt (Bt=benzotriazole) sequences were converted into either the corresponding trans- or cis-fused 2,5-diketopiperazines (DKPs) depending on the reaction conditions. Thermodynamic tandem cyclization/epimerization afforded selectively the corresponding trans-DKPs (69-75%). Complementarily, tandem deprotection/cyclization led to the cis-DKPs (65-72%). A representative set of proline-containing cis- and trans-DKPs has been prepared. A mechanistic investigation, based on chiral HPLC, kinetics, and computational studies enabled a rationalization of the results.
根据反应条件，将开链 Cbz-L-aa(1)-L-Pro-Bt（Bt=苯并三唑）序列转化为相应的反式或顺式稠合 2,5-二酮哌嗪（DKP）。热力学串联环化/差向异构化选择性地得到相应的反式 DKP（69-75%）。互补地，串联脱保护/环化得到顺式 DKP（65-72%）。已制备了一组代表性的脯氨酸顺式和反式 DKP。基于手性 HPLC、动力学和计算研究的机理研究使结果合理化。
