Characteristic Conformation of Mosher’s Amide Elucidated Using the Cambridge Structural DatabaseReport as inadecuate




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1

Division of Insect Sciences, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8634, Japan

2

Analytical Science Division, National Food Research Institute, Tsukuba, Ibaraki 305-8642, Japan

3

Department of Chemistry, Biology, and Environmental Science, Faculty of Science, Nara Womens University, Kita-Uoya Nishi-machi, Nara 630-8506, Japan





*

Author to whom correspondence should be addressed.



Academic Editor: Derek J. McPhee

Abstract 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 Racid-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 θ1 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–Cchiral bond of the methoxy moiety with an average dihedral angle θ2 of +21°; 5 the methyl group of the methoxy moiety was ap to the ipso-carbon atom of the phenyl group. View Full-Text

Keywords: chiral recognition; chirality; crystal engineering; Mosher’s method; MTPA chiral recognition; chirality; crystal engineering; Mosher’s method; MTPA





Author: Akio Ichikawa 1,* , Hiroshi Ono 2 and Yuji Mikata 3

Source: http://mdpi.com/



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