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Solution‐Phase Synthesis of Mixed Amide Libraries by Simultaneous Addition of Functionalities (SPSAF) to a Diketopiperazine Tetracarboxylic Acid Scaffold Monitored by GC Analysis of Isobutyl Alcohol
Author(s) -
Falorni Massimo,
Giacomelli Giampaolo,
Porcheddu Andrea,
Taddei Maurizio
Publication year - 2000
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(200004)2000:8<1669::aid-ejoc1669>3.0.co;2-r
Subject(s) - chemistry , amide , combinatorial chemistry , chloroformate , scaffold , solid phase synthesis , alcohol , organic chemistry , peptide , computer science , biochemistry , database
A symmetric diketopiperazine scaffold 2 has been prepared in a very simple two‐step procedure from L ‐aspartic acid dimethyl ester. This product (a tetracarboxylic acid equally protected at the two symmetric positions) has been employed as a template for the synthesis of mixed amide libraries in the solution phase using the SPSAF (simultaneous addition of functionalities) strategy. By judicious choice of the amines employed, it is possible to prepare parallel libraries containing hundreds of products using just a small number of different amines. We have also developed a simple method for monitoring the required conversion of the acid into amides based on an assay of the amount of i BuOH (determined by GC) formed during the coupling mediated by isobutyl chloroformate. We have observed that a conversion higher than 90% ( i BuOH by GC) guarantees correct formation of the desired amides. This indirect method for assessing the conversion in a combinatorial reaction employing mixed reactants (SPSAF) can conveniently be used for the routine determination of libraries prepared in the solution phase. In a broader perspective, the present results contribute as a further step in the development of new and simple systems for monitoring the progress and evolution of combinatorial reactions