The crystal of the title compound, 5-diazo-4-ethoxycarbonyl-3-methylthio pyrazole, has been prepared and determined by X-ray diffraction. The crystal belongs to the monoclinic system, space group C2/c with a = 29.174(8), b = 4.7592(12), c = 15.956(4) ? b = 117.632(4), C7H8N4O2S, Mr = 212.23, V = 1962.7(9) ?, Z = 8, Dx = 1.436 g/cm3, S = 1.000, m(MoKa) = 0.31 mm-1, T = 298(2) K, F(000) = 880, R = 0.0658 and wR = 0.1741 for 1091 independent reflections with I ≥ 2s(I). The crystal of the title compound is formed with p-p interactions through electrostatic attractions. Moreover, no HSO4- exists in the crystal structure. Therefore, only diazo pyrazole was obtained rather than either diazonium salt of the corresponding pyrazole or diazoaminopyrazole when 5-amino-4-ethoxycarbonyl-3-methylthio pyrazole was diazotized with sodium nitrite, catalyzed by sulfuric acid at 0 ℃.
The crystal structure of ethyl 2-methylthio-7-phenylpyrazolo[1,5-a]pyrimidine-3- carboxylate (C16H15N3O2S, Mr = 313.37) has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/n with a = 19.361(7), b = 7.595(3), c = 20.910(8) ?, β = 94.925(6)°, V = 3064(2) ?3, Z = 8, Dc = 1.359 g/cm3, μ = 0.222 mm-1, F(000) = 1312, R = 0.0546 and wR = 0.1082 for 5374 unique reflections with 3419 observed ones (I > 2σ(I)). The results show that all ring atoms in the pyrazolopyrimidine moiety are coplanar with strong tensile force. The structure analysis indicates that the single crystal contains strong nonclassical hydrogen bonds.
The condensation reactions of 5-amino-4-cyano-3-substituted-1H-pyrazole 2 or 3 with enaminones 1 in the presence of glacial acetic acid gave twelve new 7-aryl-3-cyano-2-substituted pyrazolo[1,5-a]pyrimidines 4 and 5 at room temperature. Their structures were characterized by elemental analysis, IR and 1H NMR. The structure of 4a was further confirmed by X-ray crystallography analysis. A plausible reaction mechanism for the formation of the title compounds was also proposed. The bioassay tests showed that compounds 4a, 4e, 4e, 4f, 5a and 5d possessed moderate herbicidal activity.
The title compound, C16H14N4S, has been synthesized by the reaction of pentane-2,4-dione with 5-amino-3-benzylthio-4-cyano-1-H-pyrazole in ethanol, and its crystal structure was determined by X-ray diffraction method. The crystal is of monoclinic, space group P21/n with a = 8.699(3), b = 23.139(9), c = 7.536(3) ? b = 92.400(8), V = 1515.5(10) 3, Z = 4, Mr = 294037, Dc = 1.290 g/cm3, = 0.71073 ? (MoKa) = 0.212 mm-1 and F(000) = 616. The structure was refined to R = 0.0533 and wR = 0.1141 for 2672 unique reflections with Rint = 0.06. The structure is a dimmer linked by intermolecular contact S(1)…HC(8) with the S(1)C(8) distance of 3.875 and the angle of 164.8.
