Intramolecular hydrogen bonding in imidazole-4(5)-alkoxycarbonyl-5(4)-carboxamide derivatives

The ir spectrum of imidazole derivatives, which have an alkoxycarbonyl group and a carboxamide group at the 4- and 5-positions of the imidazole ring respectively, exhibits the shift of the ester carbonyl band to a lower wave number. This phenomenon was investigated by spectroscopic measurements of a group of relevant compounds. The results indicate that the shift is caused by the intramolecular hydrogen bonds between the hydrogen atom of the amide and the carbonyl oxygen of the ester which is enhanced by the resonance stabilization of the imidazole ring.     

Sparfloxacindium tetrabromidocuprate(II) monohydrate crystal structure

Structure solution has been carried out for a compound containing doubly charged sparfloxacindium cation, namely ((C₁₉H₂₄F₂N₄O₃)[CuBr₄] · H₂O (I), where C₁₉H₂₂F₂N₄O₃ is sparfloxacin. The crystals of I are orthorhombic with a = 14.533(4) Å, b = 12.557(4) Å, c = 29.370(9) Å, V = 2360(3) ų, space group Pbca, Z = 8. In compound I, unlike in similar compounds of other fluoroquinolones, the second proton is attached to the sparfloxacin through the amino nitrogen atom instead of being attached through the ketone oxygen atom. This specific protonation feature of SfH is manifested in the specifics of supramolecular organization of I.     

The crystal structure of 1-(4-chlorophenyl)-3-(4-methylbenzoyl)thiourea

1-(4-Chlorophenyl)-3-(4-methylbenzoyl)thiourea was synthesized and characterized by IR,¹H and ¹³C NMR, mass spectroscopy and the elemental analysis. The crystal structure was confirmed from single crystal X-ray diffraction data. It crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a=12.038(3), b=6.330(6), c=18.912(5) Å and β=100.32(3)°. There is a strong intramolecular hydrogen bond of the type N?H...O, with distance N1...O1=2.659(3) Å. The structure is composed of dimers related by inversion centers. The dimers are formed by intermolecular interactions of the type N?H...S with N...S separation of 3.440(2) Å. The mass fragmentation pattern has also been discussed.     

Molecular and crystal structure of 4-acetyl-3-(5-nitrofurfuryl)-1-(4-chlorobenzylidene)-thiosemicarbazide

Krasnodarsk Polytechnical Institute. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 3, pp. 149–151, May–June, 1992.     

Molecular and crystal structure of 3,3-dimethyl-5-(2-naphthyl)-1-(4-nitrophenyl)-3,5a-dihydro-1H-azireno[1,2-c]imidazole

An X-ray study of 3,3-dimethyl-5-(2-naphthyl)-1-(4-nitrophenyl)-3,5a-dihydro-1H-azireno[1,2-c]imidazole revealed that the pyrazoline cycle has an envelope conformation. The endocyclic C=N double bond is slightly twisted. Quantum chemical calculations showed that this ring conformation is due to intramolecular interactions and is typical for substituted bicyclic aziridines.     

Selective alkylation of imidazole-4(5)-carboxamides

Alkylation of imidazole-4(b)-carboxamides by alkyl halides or dimethylsulfate leads to the selective formation of 1-alkyl-imidazole-4-carboxamides.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 475–477, April, 1990.     

Synthesis, characterization, crystal and molecular structure analysis of N-(2,4-dimethylphenyl)-6-methyl-4-(3-nitrophenyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide

A novel dihydropyrimidine (DHPM) derivative bearing a carbamoyl moiety was synthesized by an efficient three-component Biginelli reaction and was characterized spectroscopically and finally confirmed by X-ray diffraction studies. The title compound C₂₀H₂₀N₄O₄ crystallizes in the monoclinic space group P2₁/c with cell parameters a=12.8970(12) Å, b=13.6210(11) Å, c=11.8420(13) Å, β=115.860(3)°, Z=4 and V=1872.0(3) Å³. The conformation of the dihydropyrimidine ring is unusual; it is planar instead of the usual boat-like conformation. The 3-nitrophenyl ring is orthogonal to the 3,4-DHPM ring. The carbonyl group is in an anti-clinal conformation.     

Synthesis of analogs of 5(4)-aminoimidazole-4(5)-carboxamide

In order to obtain 5(4)-aminoimidazole-4(5)carboxamide antagonists, the.hydrazides of 5(4)-aminoimidazole-4(5)-carboxylic acid and 5(4)-aminoimidazole-4(5)hydroxamic acid were synthesized, and the reaction of 5(4)-bromo-4(5)sulfamoylimidazole with amines was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1421–1422, October, 1971.     

The decomposition mechanism of new solid-state 4(5)-aminoimidazole-5(4)-carboxamide coordination compounds

Imidazole ring coordination compounds are very useful models to better understand the coordination properties and the reaction mechanisms of biologically important systems. On the basis of previous work, new Co(II)-, Ni(II)- and Cu(II)-4(5)-aminoimidazole-5(4)-carboxamide coordination compounds have been synthesized and characterized by elemental analysis, UV-Vis and IR spectroscopies. Their thermal stability was determined by differential scanning calorimetry and by thermogravimetry, and the decomposition mechanisms were investigated by evolved gas analysis (EGA).     

3-氯-4-二苄胺基-5-甲氧基-2(5H)-呋喃酮的合成与晶体结构

在THF溶液中合成了标题化合物3-氯-4-二苄胺基-5-甲氧基-2(5H)-呋喃酮,并用FT-IR、UV-Vis、1HNMR、13C NMR、MS、元素分析和X-射线衍射等进行了表征。结果表明此化合物属正交晶系,空间群为Pbca,晶胞参数为:a=15.891(16),b=11.126(11),c=19.778(19),α=β=γ=90°,V=3497(6)3,Z=8,Dc=1.306Mg/m3,μ=0.234 mm-1,F(000)=1440。在化合物的分子结构中,两个苯环几乎垂直于呋喃酮平面,且它们与呋喃酮平面的两面角分别为89.38°和88.19°。     

Synthesis and crystal structure of thorium bis(hydrogenphosphate) monohydrate

Microcrystals of Th(HPO 4) 2.H 2O were hydrothermally obtained from a Th(NO 3) 4-CO(NH 2) 2-H 3PO 3-H 2O system ( T = 180 masculineC). The structure [orthorhombic, Pbca, a = 9.1968(2) A, b = 18.6382(2) A, c = 8.7871(2) A], unlike alpha-Zr(HPO 4) 2.H 2O-type layered compounds, consists of a three-dimensional framework with PO 4 tetrahedra coordinated to Th atoms. The water molecule is also coordinated to the Th atom and projected toward small channels running along the directions of the a and c axes. The ThO 6O(w) environment could be described as a highly distorted pentagonal bipyramid.     

Synthesis of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines

4-Chloroimidazo[4,5-d]-1,2,3-triazine was obtained by oxidative chlorinatlon from imidazo[4,5-d]-1,2,3-triazine-4-thione, and its reaction with nucleophilic agents and cleavage of the triazine ring to give 5-diazoimidazole-4-carbonitrile were studied. The newly synthesized diazoimidazole was subjected to C- and N-diazo coupling. It was established that 3-methylimidazo[4,5-d]-1,2,3-triazine-4-imine, formed by reaction of the diazo compound with methylamine, is capable of recyclization to 4-methylaminoimidazo[4,5-d]-1,2,3-triazine.See [1] for communication IV.Translated from Khimiya Getereotsiklicheskikh Soedinenii, No. 4, pp. 556–559, April, 1976.     

Synthesis of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines

The corresponding 5(4)-mercaptoimidazoles, from which various 5(4)-mercaptoimidazole-4(5)-carboxylic acid derivatives were synthesized, were obtained from the amide and ethyl ester of 5-diazoimidazole-4-carboxylic acid by substitution of the diazo group. 5-Diazo-imidazole-4-hydroxamic acid does not undergo substitution with sodium disulfide but does undergo cyclization to 3-N-hydroxyimidazo[4,5-d]-1,2,3-triazin-4-one under these conditions. The kinetics of the cyclization of diazoimidazoles were studied, and the interrelationship between the structure and reactivity of the latter was examined.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1550–1554, November, 1975.     

Synthesis of analogs of 5(4)-aminoimidazole-4(5)-carboxamide and purines

5-Diazoimidazole-4-carboxazide was isolated in the diazotization of 5(4)-aminoimidazole-4(5)-carboxhydrazide. The diazotization of N-substituted hydrazides of 5(4)-aminoimidazole-4(5)-carboxylic acis was studied. It is shown that the resulting diazo derivatives undergo cyclization to 3-arylideneaminoimidazo[4,5-d]-1,2,3-triazin-4-ones.See [1] for communication 7.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 984–985, July, 1979.