2,4-Dichloro-6-(3-methylpiperidin-1-yl)-1,3,5-triazine

In the title compound, C9H12Cl2N4, the piperidine ring adopts a chair conformation. The electron delocalization of the molecule is indicated by the similar C⋯N distances within the triazine ring and by the double-bond character of the C=N triazine–piperidine connectivity. Weak intramolecular C—H⋯N hydrogen bonds link the two rings within the molecule, which exhibits a pseudo-mirror plane if the methyl group is ignored. π–π Interactions between pairs of triazine rings with stacking distances of 3.521 (7) Å are observed in the crystal structure, generated via crystallographic inversion centers.

In the title compound, C 9 H 12 Cl 2 N 4 , the piperidine ring adopts a chair conformation. The electron delocalization of the molecule is indicated by the similar CÁ Á ÁN distances within the triazine ring and by the double-bond character of the C N triazine-piperidine connectivity. Weak intramolecular C-HÁ Á ÁN hydrogen bonds link the two rings within the molecule, which exhibits a pseudo-mirror plane if the methyl group is ignored. -Interactions between pairs of triazine rings with stacking distances of 3.521 (7) Å are observed in the crystal structure, generated via crystallographic inversion centers.
Comment 2,4,6-Trichloro-1,3,5-triazine is an interesting building block since it shows an unusual ability of replacement of the chlorine atoms by nucleophiles. It is often used for the construction of an array of novel complex derivatives and of a variety of structurally diverse macrocycles by sequential nucleophilic aromatic substitution processes (Sandford, 2003;Masllorens et al., 2004). Besides, it can also be used to construct a target supramolecular network. A series of substituted triazine compounds stabilized by weak intermolecular interactions such as C-H···N hydrogen bonding and π···π interaction were reported before (Thalladi et al., 1998). Crystallographic evidence for the existence of C-H···N hydrogen bonds with H···N ranges between 2.52 and 2.72 Å was communicated by Taylor & Kennard (1982).
In the title compound, C 9 H 12 Cl 2 N 4 , the methylpiperidine group adopts a chair conformation and the chiral C6 atom is in S * configuration ( Figure 1). If the methyl group at the piperidine group is replaced by a hydrogen atom, the molecule is nearly mirror symmetrical. The crystal data shows that the N-C bond lengths of N1-C7, N3-C4 and N3-C8 are 1.330 (5), 1.344 (5) and 1.340 (5) Å respectively. These relative homogeneous bond distances indicate the inflexibility of the molecule. Though no classic hydrogen bond is found, there is evidence of weak C-H···N interactions in the molecule (Table 1). In contrast to these inflexible intramolecular C-H···N hydrogen bonds, an example of intramolecular C-H···N hydrogen bond interactions showed a stabilizing effect in the conformation of flexible pyranoid rings (Ciunik, 1997). Fig. 2 shows the packing diagram and the stacking between pairs of pyrazine rings. The stacking distance between the ring centroids Cg···Cg i is 3.521 (7) Å, indicating quite strong π···π interactions between the symmetry-related molecules (symmetry code: -x, 1 -y,1 -z). This face to face π···π interaction plays a very important function in stabilizing the crystal structure (Hunter & Sanders, 1990).
Experimental 2,4,6-Trichloro-1,3,5-triazine (1.84 g, 10 mmol) and 3-methylpiperidine (0.99 g, 10 mmol) were dissolved in the mixture of acetone (25 ml) and H 2 O (5 ml) in the presence of KOH (0.56 g, 10 mmol) and refluxed for 24 h. The conversion of reaction was monitored by TLC. After the mixture was cooled to room temperature, the solution was filtered and rotated in vacuum. A white solid was obtained after purification by column chromatography on silica gel (n-18 hexane). Colorless crystals suitable for single-crystal X-ray diffraction studies were obtained by slow evaporation of a solution in ethanol at room temperature over several days.

Refinement
Positional parameters of all the H atoms were calculated geometrically and were allowed to ride on the C atoms to which they are bonded, with U iso (H) = 1.2U eq (C).  Fig. 1. View of the molecular structure of the title compound with the atomic numbering scheme. Displacement ellipsoids were drawn at the 30% probability level. 2,4-Dichloro-6-(3-methylpiperidin-1-yl)-1,3,5-triazine Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.