The reactivity of N-2-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxopyrimidinyl)-L-histidine towards copper(II) ions

The acid–base properties of the N-substituted amino acid HL [HL = N-2-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxopyrimidinyl)-L-histidine] and its reactivity towards the Cu^II ion have been measured by potentiometric and spectrophotometric techniques in aqueous solution at 25 °C and 0.1 M KCl ionic strength. These studies show that the neutral HL compound is present in aqueous solution (3–7 pH range) in the zwitterionic form with the diprotonated imidazolic residue. Studies of HL/Cu^II mixtures reveal the existence of complex species with the neutral ligand, HL and containing the deprotonated L ligand. By controlling the reaction conditions, four solid phases of stoichiometry: CuLCl(H₂O)₆, Cu₂LCl₃(H₂O)₈, CuL₂(H₂O)₆ and Cu(HL)₂Cl₂(H₂O)₆ were isolated and characterised by i.r. and electronic spectroscopy, thermal techniques and magnetic measurements.     

The stability and thermodynamic functions of 4-amino-1,6-dihydro-1-methyl-2-methylthio-5-nitroso-6-oxo-pyrimidine complexes with Zn(II), Cd(II) and Hg(II)

The stability constants of the complexes formed by 4-amino-1,6-dihydro-1-methyl-2-methylthio-5-nitroso-6-oxo-pyrimidine with Zn(II), Cd(II) and Hg(II) ions, in aqueous media at different ionic strengths and temperatures, have been calculated by Bjerrum's method.From the data obtained, the thermodynamic functions of complexation processes are reported.     

Reactivity of N-(6-amino-3-methyl-5-nitroso-4-oxo-3,4-dihydro- pyrimidin-2-yl)glycine with FeII,CoII, NiII,CdII and HgII metal ions

Reactions of N-(6-amino-3-methyl-5-nitroso-4-oxo-3,4-dihydropyrimidin-2-yl)glycine with N^III and Cd^II ions in 1:1 and 1:4 metal:ligand ratios, in aqueous media at 35°C and 0.1m KCl ionic strength, were studied by potentiometric methods to determine the complex species equilibria formation and their formation constants.Solid complex species from M^II/ligand systems (M^II=Fe^II, Co^II, Cd^II and Hg^II) in aqueous media were isolated and characterized by analytical data, spectroscopic methods (i.r.,¹ H-n.m.r., ¹³C-n.m.r. and electronic), and thermal and magnetic measurements.     

The selective preparation of 1,4-diaryl-6-methyl- and 1,6-diaryl-4-methyl-2-(1H)pyrimidinones

N-Phenylurea reacted with benzoylacetone derivatives (I) to give 1,4-diaryl-6-methyl-2-(1H)pyrimidinones (II) in addition to low yields of 1,6-diaryl-4-methyl-2-(1H)pyrimidinones (IV), while N-phenylthiourea afforded only 1,6-diaryl-4-methyl-2-(1H)pyrimidinethiones (III) in good yields. Further 1,6-diaryl-4-methyl-2-(1H)- pyrimidinethiones (III) were successfully converted in satisfactory yields into the corresponding 2-(1H)-pyrimidinones (IV) by the treatment with methyl iodide in the presence of sodium methoxide in methanol at room temperature.     

4-(1-Adamantylamino)-2-amino-6-methoxy-5-nitrosopyrimidine

The title compound, C₁₅H₂₁N₅O₂, lies on a crystallographic mirror plane and is hydrogen bonded to neighbouring mol­ecules by infinite chains formed by combinations of strong N—H⃛N and soft C—H⃛O hydrogen bonds. The pyrimidine moiety shows extensive delocalization.     

2-甲基-6-对甲苯基-1,6-庚二烯的合成

以对甲苯乙酮(1)为原料, 经烯醇硅醚化, Lewis酸催化Michael加成反应和Wittig反应, 合成了新倍半萜烯化合物2-甲基-6-对甲苯基-1,6-庚二烯.     

Complexing reactions in the Ni(II)-5-methyl-4-amino-3-thiooxo-1,2,4-triazapentene-1-methanal and Ni(II)-5-methyl-4-amino- 3-thiooxo-1,2,4-triazapentene-1-propanone triple systems

Complexing processes in the Ni^II-TTA-methanal (A) and Ni^II-TTA-propanone (B) triple systems (TTA–5-methyl-4-amino-3-thiooxo-1, 2, 4-triazapentene-1) in ethanol solution and nickel(II)hexacyanoferrate(II) gelatin-immobilized matrix have been studied. In the Ni^II-TTA- methanal system, formation of Ni^II oligomeric coordination compounds in which metal chelate cycles are connected by–H₂C–O–CH₂–structural groups, takes place. In the Ni^II-TTA-propanone triple system, formation of only Ni^II complexes with TTA takes place. No complexing process in the triple systems in nickel(II)hexacyanoferrate(II) gelatin-immobilized matrix was found.     

Synthesis of 1,6-dihydro-5-hydroxy-6-oxo-3-(trifluoromethyl)-4-pyridazinecarboxylates

The reaction of 2-(alkylamino)-3-(trifluoroacetyl)butenedioates 2a-b with alkyl and aryl hydrazines in ether provides 1,6-dihydro-6-oxo-3-(trifluoromethyl)-4-pyridazinecarboxylates as their alkylamine salts 3a-g . The structures of these products are substantiated using 2D nmr and ¹⁵N nmr techniques.     

Tautomerism of 1-methyl-5-amino-2,3-dihydro-1,2,4-triazolium-1-alkylidene(or arylidene)-2-methylaminoguanidinium iodide

¹H and ¹³C NMR spectroscopy has been used to examine the structures of the products of the condensation of aldehydes and ketones with 1-methyl-1-aminoguanidinium iodide, which in some instances in solution are involved in a ring-chain tautomeric equilibrium between 1-methyl-5-amino-2,3-dihydro-1,2,4-triazolium iodide and 1-alkylidene(or arylidene)-2-methylaminoguanidinium iodide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1071–1074, August, 1987.