2-Amino-4-(1-naphthyl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile and 2-amino-7,7-dimethyl-4-(1-naphthyl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile

Abstract

Syntheses and X-ray structural investigations have been carried out for the two title compounds, C(20)H(16)N(2)O(2), (IIIa), and C(22)H(20)N(2)O(2), (IIIb). In (IIIa), the heterocyclic ring adopts a sofa conformation, while in (IIIb), the ring has a flattened boat conformation. In both molecules, the fused cyclohexenone ring adopts a sofa conformation. The dihedral angles between these two flat fragments are 3.5 (2) and 17.5 (2) degrees in (IIIa) and (IIIb), respectively. The dihedral angles between the pseudo-axial naphthalene substituents and the planes of the pyran rings are 90.9 (1) and 96.7 (1) degrees, respectively. In the crystal structure of (IIIa), intermolecular N-H.N and N-H...O hydrogen bonds link the molecules into infinite tapes along the b axis, while molecules of (IIIb) form centrosymmetric dimers via N-H...N hydrogen bonds, with only one H atom of the NH(2) donor group taking part in hydrogen bonding.

5-Acetyl-2-amino-6-methyl-4-phenyl-4H-pyran-3-carbonitrile and 2-amino-5-benzoyl-6-methyl-4-phenyl-4H-pyran-3-carbonitrile acetonitrile solvate

“…In (III), the acetonitrile solvent molecules do not participate in hydrogen bonds and do not form any short intermolecular contacts. Most of the geometric parameters in the molecules are very similar to standard values (Allen et al, 1987) and previous results on related compounds (Nesterov et al, 2004(Nesterov et al, , 2005.…”

“…Similar to related compounds (Nesterov et al, 2004), both (II) and (III) display a conjugation between the donor NH 2 and the acceptor CN groups via the C2 C3 double bond. In addition, the H atoms of the NH 2 group participate in inter-molecular NÐHÁ Á ÁN and NÐHÁ Á ÁO hydrogen bonds.…”

“…Compounds (II) and (III) were obtained by the reaction of benzylidenemalononitrile, (I), with acetylacetone and benzoylacetone, respectively, according to the literature (Nesterov & Viltchinskaia, 2001;Nesterov et al, 2004). The precipitates were isolated and recrystallized from ethanol for (II) (m.p.…”

N—H...O and N—H...N interactions in three pyran derivatives

“…As was described previously for related compounds (Nesterov et al, 2004(Nesterov et al, , 2006, there is conjugation in all three title compounds between the donor (NH) and acceptor (C-NO 2 ) groups via the C4 C5 double bond. Thus, in all three molecules, the C5-N2 distances are shorter than the average conjugated C-N single bond (1.370 Å ) found in the Cambridge Structural Database (Version 5.33; Allen, 2002) ( Table 3).…”

“…This seems to be a common feature in related structures (Nesterov et al, 2004(Nesterov et al, , 2006Nesterov & Viltchinskaia, 2001).…”