Crystal structure and self-assembly on graphite of a pyrazolo[1,5-c]pyrimidine derivative

The crystal structure of the heterocyclic compound 2-(4-methoxyphenyl)-7-phenylpyrazolo[1,5-c]pyrimidine, C19H15N3O, has been determined and its self-assembly on the surface of graphite has been examined using atomic force microscopy (AFM). The title compound crystallized in the monoclinic space group P21/c, with two independent molecules in the asymmetric unit. The packing of the L-shaped molecules in the crystal is governed by arene interactions, in the absence of any conventional hydrogen-bonding interactions. The packing arrangement reveals four types of dimeric motifs stabilized by π–π and C—H...π interactions. At low coverage, molecules assemble into long needle-like islands on the graphite surface. High-resolution AFM images reveal that the molecules interact through weak noncovalent interactions between the aromatic H atoms and the methoxy O atoms.

THE EFFECT OF PIR-20 COMPOUND ON COGNITIVE DEFICIT REDUCTION IN EXPERIMENTAL GLOBAL CEREBRAL ISCHEMIA IN RATS

A study was conducted to assess the effect of a new pyrimidine derivative PIR-20 (50 mg/kg) on the development of cognitive deficits in the conditions of global cerebral ischemia in rats. The study was performed on 40 male Wistar rats weighing 200–220 g, divided into 4 groups of 10 individuals. False-operated rats and negative control animals were injected with a suspension of purified water and tween-80, the third group of animals received Cavinton (3,2 mg/kg), the fourth — PIR-20 (50 mg/kg). All test subjects were injected intraperitoneally for ten days prior to surgery. The number of dives increased to 100%, while the decision-making time decreased by 55,2% (p<0,05) in the extrapolation escape test against the background of the PIR-20 compound administration. 75% of the animals treated with PIR-20 did not re-visit the dark compartment, and the time of entering the dark chamber increased by 172,9% (p<0,05) as compared to the group of negative control rats in the test of passive avoidance of the avesir environment. It was confirmed that the studied compound PIR-20 contributes to the improvement of cognitive and mnestic functions, which is confirmed by the results of tests of passive and active aversive environment avoidance. The obtained effect exceeded the results of the control group and the reference drug Cavinton.