Crystal structures of (E)-(3-ethyl-1-methyl-2,6-di-phenyl-piperidin-4-yl-idene)amino phenyl carbonate and (E)-(3-isopropyl-1-methyl-2,6-di-phenyl-piperidin-4-yl-idene)amino phenyl carbonate.

B Raghuvarman,R Sivakumar,V Thanikachalam,S Aravindhan

doi:10.1107/s1600536814018893

B Raghuvarman, R Sivakumar + Show 2 more

Open Access

https://doi.org/10.1107/s1600536814018893

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Abstract

In the title compounds, C27H28N2O3, (I), and C28H30N2O3, (II), the conformation about the C=N bond is E. The piperidine rings adopt chair conformations with the attached phenyl rings almost normal to their mean planes, the dihedral angles being 85.82 (8) and 85.84 (7)° in (I), and 87.98 (12) and 86.42 (13)° in (II). The phenyl rings are inclined to one another by 52.87 (8)° in (I) and by 60.51 (14)° in (II). The main difference in the conformation of the two compounds is the angle of inclination of the phen-oxy-carbonyl ring to the piperidine ring mean plane. In (I), these two planes are almost coplanar, with a dihedral angle of 2.05 (8)°, while in (II), this angle is 45.24 (13)°. In the crystal of (I), mol-ecules are linked by C-H⋯O hydrogen bonds, forming inversion dimers with R 2 (2)(14) loops. The dimers are linked via C-H⋯π inter-actions forming a three-dimensional network. In the crystal of (II), there are no significant inter-molecular inter-actions present.

Highlights

The main difference in the conformation of the two compounds is the angle of inclination of the phenoxycarbonyl ring to the piperidine ring mean plane
We report on the synthesis and crystal structures of (E)-(3ethyl-1-methyl-2,6-diphenylpiperidin-4-ylidene)amino phenyl carbonate, (I), and (E)-(3-isopropyl-1-methyl-2,6-diphenylpiperidin-4-ylidene)amino phenyl carbonate, (II)
For both compounds (I) and (II), the bond lengths and bond angles are comparable with the values reported for the 3methyl derivative (III), (E)-3-methyl-1-methyl-2,6-diphenylpiperidin-4-one O-phenoxycarbonyl oxime (Raghuvarman et al, 2014)

Summary

Chemical context

Piperidine derivatives are one of the simplest heterocyclic units found in nature, for example in several alkaloids. Such compounds have been used as antihistamines, anaesthetics, tranquilizers and hypotensive agents (Robinson, 1973). The synthesis and biological activity of piperidin-4-one derivatives has received considerable attention (Parthiban et al, 2009; Narayanan et al, 2012). Both natural and synthetic piperidine derivatives have high pharmaceutical value, our interest in the synthesis of 2,6-disubstituted piperidine derivatives. We report on the synthesis and crystal structures of (E)-(3ethyl-1-methyl-2,6-diphenylpiperidin-4-ylidene)amino phenyl carbonate, (I), and (E)-(3-isopropyl-1-methyl-2,6-diphenylpiperidin-4-ylidene)amino phenyl carbonate, (II)

Structural commentary

Supramolecular features

Database survey

Refinement