4,6-Dimethoxy-2-(methylsulfanyl)pyrimidine

The title compound, C7H10N2O2S, is essentially planar [maximum deviation 0.018 (4) Å]. In the crystal, molecules are linked into chains by C—H⋯N hydrogen bonds and the chains are arranged in layers parallel to the ab plane.

The title compound, C 7 H 10 N 2 O 2 S, is essentially planar [maximum deviation 0.018 (4) Å ]. In the crystal, molecules are linked into chains by C-HÁ Á ÁN hydrogen bonds and the chains are arranged in layers parallel to the ab plane.

Comment
Purine and pyrimidine derivatives are the constituents of nucleic acids and play important roles in many biological systems (Salas et al., 1995). 2-Thiopyrimidine shows a strong bacteriostatic activity in vitro on E. coli (Holy et al., 1974). Some aminopyrimidine derivatives are used as antifolate drugs (Hunt et al., 1980;Baker & Santi, 1965). The crystal structure of the title compound is presented here.
The molecules are linked into chains by C-H···N hydrogen bonds (Table 1). The chains are arranged in layers parallel to the ab plane ( Fig.2).

Experimental
Hot methanol solution (20 ml) of 4,6-dimethoxy-2-methylthiopyrimidine (46 mg, Aldrich) was warmed over a heating magnetic stirrer for 5 minutes. The resulting solution was allowed to cool slowly at room temperature. Crystals of the title compound appeared from the mother liquor after a few days.

Refinement
H atoms were positioned geometrically [C-H = 0.93-0.96 Å] and refined using a riding model with U iso (H) = 1.2U eq (C) and 1.5U eq (methyl C). A rotating-group model was used for the methyl groups. Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. 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 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq S1 0.6163 (