Regular Article
Assignment of absolute configuration of chiral carboxylic acids via exciton-coupled CD treatment: 4-phenylthioproline as a case study†
Lorenzo Di Bari,
Serena Mannucci,
Gennaro Pescitelli,
Piero Salvadori,
Lorenzo Di Bari
Centro di Studio del CNR per le Macromolecole Stereordinate e Otticamente Attive, Dipartimento di Chimica e Chimica Industriale, Pisa, Italy
Search for more papers by this authorSerena Mannucci
Laboratori Guidotti S.p.A., S. Piero a Grado (PI), Italy
Search for more papers by this authorGennaro Pescitelli
Centro di Studio del CNR per le Macromolecole Stereordinate e Otticamente Attive, Dipartimento di Chimica e Chimica Industriale, Pisa, Italy
Search for more papers by this authorCorresponding Author
Piero Salvadori
Centro di Studio del CNR per le Macromolecole Stereordinate e Otticamente Attive, Dipartimento di Chimica e Chimica Industriale, Pisa, Italy
Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Pisa, via Risorgimento 35, I-56126 Pisa, ItalySearch for more papers by this authorLorenzo Di Bari,
Serena Mannucci,
Gennaro Pescitelli,
Piero Salvadori,
Lorenzo Di Bari
Centro di Studio del CNR per le Macromolecole Stereordinate e Otticamente Attive, Dipartimento di Chimica e Chimica Industriale, Pisa, Italy
Search for more papers by this authorSerena Mannucci
Laboratori Guidotti S.p.A., S. Piero a Grado (PI), Italy
Search for more papers by this authorGennaro Pescitelli
Centro di Studio del CNR per le Macromolecole Stereordinate e Otticamente Attive, Dipartimento di Chimica e Chimica Industriale, Pisa, Italy
Search for more papers by this authorCorresponding Author
Piero Salvadori
Centro di Studio del CNR per le Macromolecole Stereordinate e Otticamente Attive, Dipartimento di Chimica e Chimica Industriale, Pisa, Italy
Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Pisa, via Risorgimento 35, I-56126 Pisa, ItalySearch for more papers by this author†
Dedicated to Prof. Ernest L. Eliel on his 80th birthday.
Abstract
The 4-hydroxybenzoate chromophore was used as an exciton reporter group for the assignment of the absolute configuration of a chiral carboxylic acid of pharmaceutical interest, (−)-(2S,4S)-4-phenylthioproline, precursor of the ACE-inhibitor zofenopril. The nondegenerate coupling with the preexisting phenylthio chromophore was observed. A detailed conformational analysis, accomplished by means of 1H-NMR NOESY and semiempirical PM3 computational methods, and quantitative CD calculations were necessary to substantiate the assignment based on a weak experimental couplet. Chirality 14:611–617, 2002. © 2002 Wiley-Liss, Inc.
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