2-Methyl-4,6-bis(1-methylhydrazino)pyrimidine

In the title compound, C7H14N6, the amine groups of the two methylhydrazino substituents are orientated in the opposite direction to the methyl substituent at the 2-position of the pyrimidine ring. The molecule is almost planar with only the two amine N atoms lying substantially out of the mean plane of the pyrimidine ring [by 0.1430 (2) and 0.3092 (2) Å]. The H atoms on these amine groups point inwards towards the aromatic ring, such that the lone pair of electrons points outwards from the molecule. Each molecule is linked to two others through N—H⋯N hydrogen bonds between the two amino groups, forming a one-dimensional chain in the [010] direction. Offset face-to-face π–π stacking interactions between the pyrimidine rings organize these chains into a two-dimensional array [centroid–centroid distance = 3.789 (2) Å].

In the title compound, C 7 H 14 N 6 , the amine groups of the two methylhydrazino substituents are orientated in the opposite direction to the methyl substituent at the 2-position of the pyrimidine ring. The molecule is almost planar with only the two amine N atoms lying substantially out of the mean plane of the pyrimidine ring [by 0.1430 (2) and 0.3092 (2) Å ]. The H atoms on these amine groups point inwards towards the aromatic ring, such that the lone pair of electrons points outwards from the molecule. Each molecule is linked to two others through N-HÁ Á ÁN hydrogen bonds between the two amino groups, forming a one-dimensional chain in the [010] direction. Offset face-to-facestacking interactions between the pyrimidine rings organize these chains into a two-dimensional array [centroid-centroid distance = 3.789 (2) Å ].

Related literature
For the use of related compounds in the synthesis of molecular strands see: , , Gardinier et al. (2000).

S1. Comment
Although 1 is unstable in air, we were able to isolate X-ray quality crystals. Compound 1 was prepared in quantitative yield through the reaction of methylhydrazine and 4,6-dichloro-2-methylpyrimidine under an inert N 2 atmosphere. In 1 the amine groups (N4 and N6) were orientated in the opposite direction to the methyl group (C5). The molecule was planar with only N4 and N6 being out of the mean plane of the pyrimidine ring by 0.1430 (2) and 0.3092 (2) Å, respectively. The hydrogen atoms on these amine groups were located from difference Fourier maps and freely refined.
They pointed inwards towards C3 such that the lone pair of electrons on N4 and N6 pointed outwards from the molecule.
Each molecule of 1 was linked to two others through H-bonding between N4 and N6 ( Figure 2). The N6-H···N4 distance was measured as 2.177 (16) Å, which corresponded to a N6···N4 distance of 3.093 (2) Å. This H-bond linked molecules of 1 together to form a one dimensional chain in the [0 1 -1] direction. The angle between the planes of adjacent H-bonded molecules was 72.97 (1)°. Offset, face-to-face π-π stacking interactions between the pyrimidine rings organized these chains into a two dimensional array. The centroid to centroid distance for this π-π interaction was 3.789 (2) Å.

S2. Experimental
Under magnetic stirring, 4,6-dichloro-2-methylpyrimidine, (0.4792 g, 2.94 mmol) dissolved in EtOH (30 ml), was added by portions over 20 min to ice cooled methylhydrazine (2.00 ml, 38.0 mmol) flushed with Ar. The mixture was refluxed for 6 h under an inert atmosphere of N 2 . After cooling, residual methylhydrazine and EtOH were evaporated, K 2 CO 3 (1.025 g) and CHCl 3 (50 ml) were added to the solid residue, and the mixture was stirred for 20 min. The liquid phase was filtered and the solid was washed with more CHCl 3 (50 ml then 30 ml). The combined liquid fractions were evaporated and the resulting solid was dried in vacuo to gave 1 as a white solid ( CN str). Crystals suitable for X-ray determination were grown by slow evaporation of a CDCl 3 solution of 1.

S3. Refinement
All H-atoms bound to carbon were refined using a riding model with d(C-H) = 0.93 Å, U iso =1.2U eq (C) for the CH H atoms and d(C-H) = 0.96 Å, U iso =1.5U eq (C) for the CH 3 H atoms. All H-atoms bound to nitrogen were located from difference Fourier maps and freely refined with U iso =1.5U eq (N).  The asymmetric unit of (1) showing the atom numbering with displacement ellipsoids drawn at the 50% probability level.

Figure 2
View of the arrangement of 1 into one-dimensional chains through H-bonding and organization of the chains into a twodimensional array through π-π stacking. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.20 e Å −3 Δρ min = −0.21 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. 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 > σ(F 2 ) is used only for calculating R-factors(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.