Reactions of crystalline (R)-(-)- and (S)-(+)-mandelic acid with amines. Crystal structure and dipole moment of (S)-mandelic acid. A method of determining absolute configuration of chiral crystals

Co‐crystallization with Nicotinamide in Two Conformations Lowers Energy but Expands Volume

“…As a control, calculations were performed that began with the 100 K structure of RMA and the room‐temperature structure of ( S ) ‐ mandelic acid (SMA, FEGHAA) . Given that RMA and SMA are related by symmetry, their energies must be identical at the same temperature.…”

“…As a control, calculations were performed that began with the 100 K structure of RMA and the room-temperature structure of (S)-mandelic acid (SMA, FEGHAA). 22 Given that RMA and SMA are related by symmetry, their energies must be identical at the same temperature. The actual minimizations indeed yielded identical unit cells (Table 1) and energies (within 0.01 kJ/mol) within the error of the method.…”

Enantiomer self‐disproportionation of chiral compounds on achiral ordered mesoporous silica M41S and regular silica gel as a stationary phase

“…3A and 3B, respectively) that the mode of hydrogen bonding significantly differs from each other. [29][30][31] Although this behavior may not exactly occur in solutions, nevertheless, in a similar manner, it reflects possibility of existence of homochiral and heterochiral agglomerations in solution, the extent of which would depend upon the nature of the solvent. This assumption is further supported by the observations from the fact that the ee obtained for the separation of same analyte was different in different solvents ( Table 4).…”

Oxonium (R)-O-acetylmandelate

“…A search of the January 1992 release of the Cambridge Structural Database (Allen, Kennard & Taylor, 1983) yielded no 'hits' for an Oacetylmandelate fragment, but did reveal numerous structures which contain the parent mandelate [PhCH(O)CO2] moiety. Three of these structural determinations were on the parent mandelic acid molecule [PhCH(OH)CO2H] (Cameron & Duffin, 1974;Wei & Ward, 1977;Patil, Pennington, Paul, Curtin & Dykstra, 1987); the first two studies were on DL-mandelic acid, the last on (S)-(+)mandelic acid. The conformation reported for the DLracemate (torsion angles OcarboxylatemCsp2mCsp3--Car 77.3 and -102.0°; Ocarboxylate--Csp2--Csp3--Ohydroxyl 23.9 and -156.7 ° ) is similar to that found here in PhCH(OAc)CO2-[Ocarboxylate--Csf m Csp3 --Car 84.6(2) and -92.3(2)°; Oearboxylate ~Csp 2 ~CsP 3-Oacetyl 26.4(1) and -156.7(3)°], even though the crystal enviroument is quite different.…”