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Characteristic Conformation of Mosher’s Amide Elucidated Using the Cambridge Structural Database
Conformations of the crystalline 3,3,3-trifluoro-2-methoxy-2-phenylpropanamide derivatives (MTPA amides) deposited in the Cambridge Structural Database (CSD) were examined statistically as R(acid)-enantiomers. The majority of dihedral angles (48/58, ca. 83%) of the amide carbonyl groups and the trif...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6332137/ https://www.ncbi.nlm.nih.gov/pubmed/26193245 http://dx.doi.org/10.3390/molecules200712880 |
Sumario: | Conformations of the crystalline 3,3,3-trifluoro-2-methoxy-2-phenylpropanamide derivatives (MTPA amides) deposited in the Cambridge Structural Database (CSD) were examined statistically as R(acid)-enantiomers. The majority of dihedral angles (48/58, ca. 83%) of the amide carbonyl groups and the trifluoromethyl groups ranged from –30° to 0° with an average angle θ(1) of −13°. The other conformational properties were also clarified: (1) one of the fluorine atoms was antiperiplanar (ap) to the amide carbonyl group, forming a staggered conformation; (2) the MTPA amides prepared from primary amines showed a Z form in amide moieties; (3) in the case of the MTPA amide prepared from a primary amine possessing secondary alkyl groups (i.e., Mosher-type MTPA amide), the dihedral angles between the methine groups and the carbonyl groups were syn and indicative of a moderate conformational flexibility; (4) the phenyl plane was inclined from the O–C(chiral) bond of the methoxy moiety with an average dihedral angle θ(2) of +21°; (5) the methyl group of the methoxy moiety was ap to the ipso-carbon atom of the phenyl group. |
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