M. Tokarčík

N-(2,4,6-Trimethyl­phen­yl)maleamic acid

The molecular structure of the title compound, C13H15NO3, is stabilized by a short intramolecular O—H⋯O hydrogen bond within the maleamic unit. In the crystal, intermolecular N—H⋯O hydrogen bonds link molecules into zigzag chains propagating in [010].

N-(2,6-Dimethylphenyl)benzamide

The conformation of the NH bond in the structure of the title compound (N34DMPBA), C15H15NO, is anti to the meta-methyl substituent in the aniline ring, similar to that observed with respect to the meta-chloro substituent in N-(3,4-dichlorophenyl)benzamide (N34DCPBA), but in contrast to the syn conformation observed with respect to the meta-methyl substituent in N-(3,4-dimethylphenyl)acetamide. The bond parameters in N34DMPBA are similar to those in N34DCPBA and other benzanilides. The molecules in N34DMPBA are packed into a column-like structure in the direction of the a axis through N—H⋯O hydrogen bonds.

N-(2,6-Dimethylphenyl)maleamic acid

The asymmetric unit of the title compound, C12H13NO3, contains two independent molecules. The conformation of the N—H bond and the C=O bond in the amide segment are anti to each other. The molecular conformation of each molecule is stabilized by an intramolecular O—H⋯O hydrogen bond. In the crystal, molecules are connected through intermolecular N—H⋯O hydrogen bonds. In addition, there is a carbonyl–carbonyl dipolar interaction with an O⋯C contact of 2.926 (3) Å.

N-(4-Methylphenyl)benzamide

The structure of the title compound, C14H13NO, resembles those of N-(2-chlorophenyl)benzamide, 2-chloro-N-phenylbenzamide, N-(2,3-dichlorophenyl)benzamide, N-(3,4-dichlorophenyl)benzamide and 2-chloro-N-(2-chlorophenyl)benzamide with similar bond parameters. The benzene and methylphenyl rings have a dihedral angle of 63.41 (5)°, while the amide group makes a dihedral angle of 20.5 (1)° with the benzene ring. The molecules are linked into chains in the b-axis direction by N—H⋯O hydrogen bonds.

2-Chloro-N-phenyl-acetamide.

In the title compound, C8H8ClNO, the conformations of the N—H and C=O bonds are anti to each other, but the C—Cl and C=O bonds in the side chain are syn. The molecules are linked by N—H⋯O hydrogen bonds into infinite chains running in the [101] direction.

N,N'-Bis(3-methyl-phen-yl)propane-diamide.

The molecular structure of the title compound, C17H18N2O2, is symmetrical around the central C atom. The two halves of the molecule are related by a twofold rotation axis. In each half of the molecule, the structure is stabilized by intramolecular C—H⋯O hydrogen bonds. Furthermore, each amide group is almost coplanar with the adjacent benzene ring [dihedral angle is 9.2 (2)°]. The planes of the amide groups are inclined at an angle of 68.5 (1)°, while the two benzene rings make a dihedral angle of 70.40 (3)°. In the crystal, molecules are linked by intermolecular N—H⋯O hydrogen bonds into chains running along the c axis. Neighbouring chains are weakly coupled by π–π stacking interactions [centroid–centroid distance = 3.7952 (8) Å].

N-(2,3-Dimethylphenyl)-2-methylbenzamide

In the title molecule, C16H17NO, the N—H and C=O groups are in the antiperiplanar conformation that has been observed in related compounds. Furthermore, the conformation of the C=O group with respect to the methyl substituent in the 2-methylphenyl ring is syn, as has also been observed in related structures. The amide group makes dihedral angles of 50.3 (3) and 64.6 (3)° with the 2-methylphenyl and 2,6-dimethylphenyl rings, respectively, while the angle between the planes of the two rings is 14.26 (7)°. The molecules are packed into chains via N—H⋯O hydrogen bonds. An intramolecular C—H⋯O hydrogen bond is also observed.

N-(2-Methyl-phen-yl)maleamic acid.

In the title compound, C11H11NO3, the conformation of the N—H bond is anti to the C=O bond in the amide segment, while it is syn to the ortho-methyl group in the phenyl ring. In the maleamic acid unit, the amide C=O bond is anti to the adjacent C—H bond, while the carboxyl C=O bond is syn to the adjacent C—H bond. The C=O and O—H bonds of the acid group are in the relatively rare anti position to each other. This is an obvious consequence of the intramolecular O—H⋯O hydrogen bond donated to the amide carbonyl group. The ortho-substituted phenyl ring makes a dihedral angle of 12.7 (1)° with the mean plane of the maleamic acid unit. In the crystal structure, intermolecular N—H⋯O hydrogen bonds link the molecules into zigzag chains parallel to [001]. These chains are further linked into sheet by weak π–π interactions [centroid–centroid distance = 3.425 (2) Å].

N,N′-Diphenyl­suberamide

In the title compound (systematic name: N,N′-diphenyloctanediamide), C20H24N2O2, the two phenyl rings make an interplanar angle of 76.5 (2)°. The crystal structure is stabilized by intermolecular N—H⋯O hydrogen bonds, which link the molecules into chains running along the b axis. The crystal studied was non-merohedrally twinned, the fractional contribution of the minor twin component being 0.203 (2).

2-Methyl-N-(4-methylphenyl)benzamide

The conformations of the N—H and C=O bonds in the structure of the title compound, C15H15NO, are trans to each other. Furthermore, the position of the amide O atom is syn to the ortho-methyl group in the benzoyl ring. The central amide group is tilted at an angle of 59.96 (11)° to the benzoyl ring, and the benzoyl and aniline rings form a dihedral angle of 81.44 (5)°. N—H⋯O hydrogen bonds link the molecules into infinite chains running along the c axis.