Crystal and molecular structure of 1-amino-4-methoxycarbonyl-3-methyl-8-oxopyrazolo[1,5-a]pyrimidine monohydrate from laboratory powder data

The crystal structure of 1-amino-4-methoxycarbonyl-3-methyl-8-oxopyrazolo[1 ,5-a]pyrimidine monohydrate, C9H10N4O3. H2O, from the family of pyrazolo[1, 5-a]pyrimidines which demonstrate an activity against the influenzavirus A and coxsackievirus B3, has been determined from laboratory (Guinier-Johanns on photograph) powder diffraction data using a grid search procedure. Param eters of the monoclinic cell (P2(1)/a, No. 14, Z=4) at 295 K are a=11.599(7 ) Angstrom, b=11.550(7) Angstrom, c=8.575(5) Angstrom, beta=110.76(4)degree s. Rietveld refinement (full-pattern-decomposition) gave chi(2) =4.8(4.5), R-p=0.038(0.043), R-wp=0.065(0.062). The observed microstrain-induced aniso tropy of diffraction line broadening was approximated by a quartic form in h,k,l. The obtained results allowed to distinguish between several isomers which were indistinguishable by others methods. (C) 1999 International Cent re for Diffraction Data. [S0885-7156(99)00602-8].