Atropisomerism in 3-arylthiazolidine-2-thiones. A combined dynamic NMR and dynamic HPLC study.
Sterically hindered 3-arylthiazolidine-2-thiones were prepared by a solvent-free reaction with arylisothiocyanates and 1,4-dithiane-2,5-diol. Atropisomerism was observed in two compounds (3 and 4, aryl = 1-naphthyl and 2-methylnaphth-1-yl), whose rotational energy barriers were measured using dynamic NMR and dynamic HPLC. The experimental analyses were supported by DFT calculations. Thermally stable atropisomers were obtained by dehydration of compounds 3 and 4 and the absolute configuration of the atropisomers of compound 6 was determined by theoretical simulation of the ECD and VCD spectra.
Department of Chemistry and Technologies of Drug, Sapienza University of Rome, Piazzale A. Moro 5, I-00185 Rome, Italy.
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Ciogli
Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai-625021, Tamil Nadu, India.
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Vivek Kumar
Department of Industrial Chemistry "Toso Montanari", University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy. andrea.mazzanti@unibo.it.
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Mancinelli
Department of Industrial Chemistry "Toso Montanari", University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy. andrea.mazzanti@unibo.it.
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http://orcid.org/0000-0003-1819-8863
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Mazzanti
Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai-625021, Tamil Nadu, India.
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Perumal
Department of Industrial Chemistry "Toso Montanari", University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy. andrea.mazzanti@unibo.it.
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http://orcid.org/0000-0001-6423-3928
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Severi
Department of Chemistry and Technologies of Drug, Sapienza University of Rome, Piazzale A. Moro 5, I-00185 Rome, Italy.
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http://orcid.org/0000-0002-3253-3608
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Villani