Synthesis and acid-base and thermochromic properties of 5-(2-thiazolyl)-substituted formazans

As compared with benzothiazolylformazans, the thiazole ring of synthesized 5-substituted thiazolylformazans weakens their acidic properties and decreases their tendency to form intramolecular hydrogen bonds. The thiazolylformazans have positive red-blue thermochromism. Their IR and UV spectra are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 460–463, April, 1977.     

Synthesis and spectral properties of some bis-substituted formazans

Novel, 1,4-bis-[3,3'-phenyl-5,5'-(o-carboxyphenyl)-formaz-1-yl]-benzene-o-sulphonic acid and its derivatives contained OH group at the o-, m-, p-positions of the 3-phenyl ring were synthesized. The structures of the formazans were confirmed by elemental analyses, GC-mass, IR, (1)H NMR, UV-vis spectra. Their absorption properties were investigated. It was seen that lambda(max) values shifted towards shorter wave lengths by 130nm in CSPF relative to 1,3,5-triphenylformazan (TPF) due to the fact that the structure of CSPF contained electron withdrawing COOH and SO(3)H groups (hypsochromic effect). With binding of OH group to 3-phenyl ring of CSPF, it was observed a small bathochromic effect in accordance to the electron donating effect of OH group.     

Investigations of benzazoles and naphthazoles

1-(5-Benzimidazolyl)-5-phenylformazans, which are isomers of the previously obtained 1-(2-benzimidazolyl)-5-phenylformazans, and 1-(5-benzimidazolyl)-5-(2-benzimidazolyl)formazans, which are isomers of 1,5-bis(2-benzimidazolyl)formazans, were synthesized. In contrast to their isomers, the benzimidazole ring in the formazans obtained is connected to the formazan chain at the 5 position rather than at the 2 position, and this leads to substantial differences in the properties, structures, and chromaticities of the isomeric formazans. The imidazole ring in 1-(5-benzimidazolyl)-5-phenylformazans is far removed from the chain and cannot participate in amino-imino tautomerism, in connection with which, the indicated formazans behave like 1,5-diphenylformazans and do not form complexes with metal ions in the cold. For the same reasons, 1-(5-benzimidazolyl)-5-(2-benzimidazolyl)formazans differ from the isomeric symmetrical 1,5-bis(2-benzimidazolyl)formazans by a hipsochromic shift of the long-wave maximum of the spectrum and are similar (with respect to their spectrophotometric characteristics and complexing properties) to the unsymmetrical 1-(2-benzimidazolyl)-5-phenylformazans. Conclusions regarding the state of the hydrogen bond of the formazan chain were drawn on the basis of the IR spectral data.See [1] for communication XXXI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1136–1138, August, 1971.     

Structure and color of protonated benzimidazolyl formazans

Benzimidazolyl formazans were titrated spectrophotometrically and their base constants were determined. On the basis of quantum mechanical calculations of electron spectra a hypothesis concerning the chelate structure of the unsymmetrical benzimidazolyl formazans is proposed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 822–826, June, 1985.     

Synthesis and biological activity of phosphorylated compounds of 2‐substituted benzazoles

A series of organophosphorus derivatives have been synthesized by the reaction of phosphorylchloride with 2‐(2′‐hydroxyphenyl)benzimidazole and 2‐(2′‐hydroxynaphthyl)benzimidazole in the presence of KHCO₃ in dry THF in different molar ratios. Newly synthesized derivatives were tested for their insecticidal activity against Periplenata americana. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:246–249, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20533     

QSAR of genotoxic active benzazoles

Previously synthesized 2,5-disubstituted benzoxazole and benzimidazole derivatives, were tested for their genotoxic activity in the Bacillus subtilis rec- assay. The results revealed that 5-methyl-2-(p-aminobenzyl)benzoxazole exhibited the highest genotoxic response, which was comparable to 4-nitroquinoline 1-oxide (4-NQO), the reference agent of classical positive mutagen. Among the other tested compounds, four showed a genotoxic activity. A QSAR study revealed that structural parameters IY(C(2)H(4)) and IY(CH(2)O), indicating the bridge elements between the phenyl moiety and the fused ring system at position 2 and the quantum chemical parameter (DeltaE ), showing the difference between HOMO and LUMO energies, were found significant for enhancing the genotoxic activity in these compounds. In addition, the substituent effects on positions R and R(1) were found important for the activity as well as holding a substituent possessing a maximum length with a minimum width property on position R(1) like alkyl groups. On the other hand, substituting position R with an electron donating group instead of electron withdrawing group increased the genotoxic activity.     

Synthesis and Photochromic Properties of 2-(3-Nitro-2-pyridylmethyl)benzazoles

2-(3-Nitro-2-pyridylmethyl)benzazoles were synthesized, and their photochromic properties were studied by flash photolysis. Introduction of a nitropyridyl instead of the nitrophenyl moiety into the 2-methyl group insignificantly increases the basicity of the methylene group. Nitropyridyl-substituted benzazoles give rise to three detectable photoinduced forms: the corresponding anion at pH > 10, azamerocyanine at pH 4 , and monomethinecyanine at pH 1. Irradiation of solutions of weakly basic benzoxazole and benzothiazole derivatives at pH 4 results in formation of neutral chelate structures in which the hydrogen atom is linked simultaneously to two nitrogen atoms: one in the pyridine ring, and the second, in the azole ring.     

Synthesis of coumarin/phenanthridine-fused heterocycles and their photochemical and thermochromic properties

Four coumarin and phenanthridine-fused heterocycles were efficiently synthesized using base-mediated annulation of N-alkylquinolinium iodide and coumarin as a key step. One compound is found to be sensitive to light and changes color upon UV irradiation; the others are sensitive to heat and possess negative thermochromic properties. A novel light- and heat-sensitive molecular skeleton is introduced.     

Synthesis,structure, and tautomerism of formazans that contain 1-aryl-2-benzimidazolyl residues

1,5-Bis(1-aryl-2-benzimidazolyl)-3-methyl- and 1-(p-tolyl)-3-methyl-5-(1-aryl-2-benzimidazolyl)formazans were synthesized. It was shown by IR spectroscopy (from the change in the spectral characteristics of the NH, groups) that the formazans exist in the imino form in solutions in CCl₄, whereas a tautomeric equilibrium between the amino and imino forms of the investigated compounds is observed in solutions in CHCl₃. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 818–821, June, 1980.     

Microbial screening of novel synthesized formazans having amide linkagesΦ

Formazans 5(a‐j) have been prepared by the condensation between schiff base 3 and diazonium salt of substituted 2‐amino benzothiazole 4(a‐j) . The intermediate schiff base 3 was synthesized by the condensation of p‐nitrobenzolyhydrazide 1 with thiophene‐2‐aldehyde 2 . All the compounds have been screened for their antifungal activity against Candida albicans (ATCC‐64550), Candida krusei (ATCC‐14243) and Candida parapsilosis (ATCC‐22019) and antibacterial activity against Escherchia coli (ATCC‐6538), Staphylococcus aureus (ATCC‐6538), Pseudomonas aeruginosa (ATCC‐1539) and Bacillus substilis (ATCC‐6633). The structures of the synthesised compounds 5(a‐j) have been characterized on the basis of their elemental analysis and spectral data (UV, IR, ¹H NMR, ¹³C NMR and Mass).     

Synthesis and characterization of poly(benzazoles) containing the bicyclo[2.2.2]octane moiety

Poly(benzobisoxazoles) (PBOs), poly(benzobisthiazoles) (PBTs) and copolymers thereof containing the 2,5-dihydroxybicyclo[2.2.2]octane moiety have been prepared and studied. The homopolymers were synthesized by the polycondensation of 2,5-dihydroxybicyclo[2.2.2]octane-1,4-dicarboxylic acid with 4,6-diamino-1,3-benzenediol dihydrochloride or 2,5-diamino-1,4-benzenedithiol dihydrochloride in poly(phosphoric acid). Random and block copolymers (PBO–PBT) were also prepared. The polymers were characterized by solubility, X-ray diffraction, spectroscopy (infrared and solid-state ¹³C nuclear magnetic resonance), and thermal analysis such as differential scanning calorimetry and thermogravimetric analysis. Thermogravimetric analysis showed thermal stability of the polymers above 375°C in air and under argon atmosphere. The polymers exhibited high resistance to organic and inorganic solvents. The polymers were converted to the more stable aromatic polymers via dehydration and retro Diels–Alder reactions of the 2,5-dihydroxybicyclo[2.2.2]octyl moiety by pyrolysis. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 277–281, 1998     

Investigations in the field of benzazoles and naphthazoles

1-(Alkyl benzimidazolyl)-, 1-benzothiazolyl- and 1-benzoxazolyl-3-methyl-5-phenylformazans containing sulfo groups (in the meta or para position) in the phenyl residue have been synthesized. It has been established that some of them can be used as analytical reagents.For part XXI, see [5].     

Synthesis of a number of N-ω-dimethylaminoalkylmaleimide methiodides

Conclusions A number of N-ω-dimethylaminoalkylmaleimide methiodides was obtained. Institute of Heteroorganic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2385–2386, October, 1976.     

Photochromic and thermochromic spiranes 33. Synthesis of a new indolinonaphthoxazino- bisspiropyran and investigation of its photochromic characteristics

A new unsymmetrical bisspiropyran was synthesized on the basis of 2,4-dihydroxyisophthalic aldehyde with naphthoxazinone and indoline fragments in the structure. The structure of the obtained compound was proved by the data from ¹H NMR and IR spectroscopy and X-ray crystallographic analysis. The photochromic characteristics of the obtained compound were investigated. It was established by means of the data from B3LYP/6-31G** quantum-chemical calculations that irradiation of a solution of the obtained biphotochrome with unfiltered light leads to opening of both pyran fragments. This is the first corroborated example of the twofold cleavage of C_spiro–O bonds for compounds of this class.     

四碘合汞酸银的合成及其在热致变色方面的应用

以硝酸汞、碘化钾和硝酸银为原料,在室温条件下,用液相法合成了四碘合汞酸银,并利用XRD谱和红外光谱技术对合成的四碘合汞酸银进行表征,证实了目标产物四碘合汞酸银已经形成。用扫描电镜技术观测四碘合汞酸银固体颗粒的形貌。然后采用一定方法,将合成的四碘合汞酸银分散到有机玻璃中,制得到掺有四碘合汞酸银的有机玻璃复合材料,并对该复合材料进行了热致变色的研究,发现该材料热致变色温度为48℃,而且可逆变色性能好,在热致变色方面具有应用的前景。     

Synthesis and properties of a number of salts of N-succinylmethionine

A comparative study has been made of the radioprotector activity of cystamine and the synthesized cobalt and copper salts of N-succinylmethionine. Activity falls in the sequence cystamine-copper salt-cobalt salt.Khar'kov Scientific-Research Institute of Endocrinology and Hormone Chemistry. Khar'kov Medical Institute. Khar'kov Scientific-Research Institute of Medical Radiology. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 86–88, January–February, 1990.