Laser pulse photolysis was used to study the nature and reactions of intermediates in the photochemistry of the flat dithiocarbamate complex Cu(Et(2)dtc)(2) in CCl(4). A nanosecond laser pulse (355 nm) is shown to induce intermediate absorption bands of bivalent copper complex whose coordination sphere contains a dithiocarbamate radical Et(2)dtc(?) and a chloride ion at the axial position ([(Et(2)dtc)Cu(Et(2)dtc(?))Cl(a)]). At room temperature during some microseconds after the laser pulse, this intermediate interacts with the initial complex to form presumably a dimer [Cu(2)(Et(2)dtc)(3)(Et(2)dtc(?))Cl]. The latter vanishes in the second-order reaction. Analysis of kinetic and spectral features gives the arguments for the formation of a cluster [Cu(2)(Et(2)dtc)(3)Cl-tds-Cu(2)(Et(2)dtc)(3)Cl], which produces a new absorption band at 345 nm. The cluster decomposes in ~5 ms into final products, a binuclear complex [Cu(2)(Et(2)dtc)(3)Cl] and tetraethylthiuramdisulfide (Et(4)tds). 相似文献
Unusual course of the reaction was revealed on the oxidation of functionally substituted acridine containing the activated methyl groups by well‐known oxidants, such as selenous acid and selenium(IV) oxide. Treatment of 2‐methoxy‐4,9‐dimethyl‐1‐nitroacridine ( 5 ) with an excess of H2SeO3 in boiling ethanol gave a mixture of the normal reaction products, 2‐methoxy‐4‐methyl‐1‐nitro‐9‐formylacridine ( 11 ) (isolated yield 29%) and 2‐methoxy‐4‐methyl‐1‐nitroacridine‐9‐carboxylic acid ( 12 ) (36%), together with an abnormal product, 3‐methoxy‐5‐methyl‐1H‐selenopheno[2,3,4‐k,l]acridine‐1‐one ( 13 ) (21%), which is the first example of a new seleno‐containing ring system. With the use of SeO2 the yield of selenolactone 13 was much lower. J. Heterocyclic Chem., 2011. 相似文献
The reaction between pyridine-2-carbaldehyde and zinc chloride in wet MeCN yielded a zinc chelate complex with hemiacetal formed in situ from the hydrated pyridine-2-carbaldehyde and the second molecule of pyridine-2-carbaldehyde. According to X-ray diffraction data, the pentacoordinated environment of the zinc ion is formed by two chlorine atoms and the N,N',O-tridentate ligand. In the crystal, molecules are combined into a 3D supramolecular framework due to the intermolecular hydrogen bonds O–H···Cl, C–H···Cl, and π–π stacking interactions between pyridine rings. 相似文献
An unusual cleavage of the Cpy–Cpy bond in the reaction of 2,2′-bipyridine N,N′-diimine and its C-methyl substituted derivatives with acetylenes is described. The effect of the solvent on the yield of 7,7′-bipyrazolo[1,5-a]pyridine-2,2′,3,3′-tetracarboxylates and the products of cleavage of the Cpy–Cpy bond has been studied. The mechanism of the cleavage reaction is discussed on the basis of DFT calculations. 相似文献
New analogs of fragment 113–121 of the basic protein of myelin were synthesized: Phe-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Arg, in which the phenylalanine in the first position has been replaced by L-alanine (V) and by D-phenylalanine (IX), and also a shortened analog with the deletion of the serine in the second position (XIII) and a lengthened analog with the insertion of glycine between the phenylalanine and tryptophan (XVII). In experiments on guinea pigs, one of the compounds obtained exhibited encephalitogenic activity. The circular dichroism spectra of compounds (I) and (IX), and also of some model compounds, have been studied in order to analyze the contribution of the aromatic amino acid residues to the dichroic absorption.
A comparative investigation of the acid-base properties, the polarographic behavior, and the spectral characteristics of oxochromeno- and oxothiochromenopyrazoles, oxodipyrazolopyrans, and their electronic analogs xanthone and thioxanthone, has been performed. The difference in properties is due to the electron-accepting nature of the condensed pyrazole ring.For communication III, see [8].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 990–992, July, 1973. 相似文献
The corresponding σ complexes of the Meisenheimer type, viz., anions of the potassium salts of 6H-5-nitro-6-acetonylpyrimidines,
were obtained and isolated in the reaction of 5-nitro-, 5-nitro-4-methoxy-, 5-nitro-2-methoxy-, and 5-nitro-2,4-dimethoxypyrimidines
with acetone in the presence of potassium hydroxide. The structures of the complexes were proved by means of the PMR, IR,
and UV spectra. It is shown that the acetone anion in all cases adds to the methoxy-unsubstituted position of the pyrimidine
ring, whereas nucleophilic attack takes place at the C4 atom when the 2 and 4 positions are free.
See [1] for communication 1.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 239–242, February, 1980. 相似文献