4-(4-Fluorophenyl)-6-(2-furyl)pyrimidin-2-amine

Molecules of the title compound, C14H10FN3O, are essentially planar and in the crystal structure they form dimers via hydrogen bonds, involving pyrimidinyl N atoms and amino H atoms, about inversion centers. The centroids of the furyl and pyrimidinyl rings are separated by 3.489 (2)Å, indicating π–π stacking interactions.


Comment
Compounds containing a pyrimidine moiety play a significant role in many biological systems (Hueso et al., 2003). The pyrimidine ring is present in nucleic acids, several vitamins, coenzymes and antibiotics. Pyrimidine based compounds have been reported as anticancer and antiviral agents (Miyazaki et al., 2005). They have been used as hypnotic drugs for the nervous system, e.g., barbiturates act as anaesthetic and sleeping agents and have been in use for the treatment of anxiety, epilepsy and other psychiatric disorders (Colorado & Brodbelt, 1996;Bojarski et al., 1985). We have prepared a series of pyrimidine based compounds from different chalcones following the literature method (Varga et al., 2003). In this paper we report the preparation and structure of the title pyrimidine compound, (I).
The crystal structure of (I) is composed of more or less planar molecules of 4-(4-fluorophenyl)-6-(2-furyl)pyrimidin-2yl-amine ( Fig. 1) wherein the dihedral angle between the mean-planes formed by the furyl and pyrimidinyl rings is 1.91 (12)°a nd the phenyl ring is oriented at 12.33 (11) and 10.45 (10)° with respect to these rings, respectively. The atoms F1 and N3 are displaced from the mean-planes of the phenyl and pyrimidinyl rings by 0.026 (2) and 0.032 (2) Å, respectively. The bond distances and bond angles in (I) agree well with the corresponding bond distances and angles reported in some compounds closely related to (I)(e.g., Gallagher et al., 2004;Fun et al., 2006;Miranda et al., 2006). The geometry at atom N3 is trigonal pyramidal with sum of the angles about N3 being 348.6°.
It is interesting to note that only one of the amino H-atoms, namely H31 is involved in hydrogen bonding, resulting in dimers about inversion centers ( Fig. 2) (details of hydrogen bonding geometry are given in Table 1). In addition, non-classical intermolecular hydrogen bonds, C5-H5···O1, and intramolecular interactions C2-H2···N1 were also observed. The shortest distance between the centroids of furyl and pyrimidinyl rings from adjacent molecules separated by translation along the b axis is 3.489 (2) Å indicating π-π stacking interactions.
The ethanol was removed under reduced pressure in a rotary evaporator and distilled water (20 ml) was added to the residue.
The product was isolated as precipitates, washed repeatedly with pure water and recrystallized from chloroform (yield 58%).

Refinement
Though all the H atoms could be distinguished in the difference Fourier map the H-atoms bonded to C-atoms were included at geometrically idealized positions and refined in riding-model approximation with the following constraints: C-H distances were set to 0.95 Å and U iso (H) = 1.2U eq (C). H-atoms bonded to N3 were taken from the difference map and were allowed to refine with U iso = 1.2 times U eq of N3. The final difference map was free of any chemically significant features. Fig. 1. ORTEP-3 (Farrugia, 1997) drawing of (I) with displacement ellipsoids plotted at 50% probability level.   (7) 0.0004 (7) 0.0051 (7) Geometric parameters (Å, °)