Synthesis of 5,12-diazadibenz[a,h]anthracene

5, 12-Diazadibenz[a,h]anthracene ( 20 ) was synthesized in 21% overall yield for seven steps. Salient features of the synthesis include the initial, one-step conversion of trans, trans-1,4-bis-(β-nitrovinyl)benzene into 2,2″-dinitro-p-terphenyl by Diels-Alder condensation plus elimination, monocyclization of the derived 2,2″-diformylamino-p-terphenyl to give 8-(2-amino-1-phenyl)-phenanthridine ( 10 ) in the presence of fortified polyphosphoric acid, and accomplishment of a second cyclization step only after reduction of the heteroring in 10 (by means of diisobutyl-aluminum hydride) plus formylation. The 6-methyl and 6,13-dimethyl derivatives of 20 were prepared similarly.     

Common and Specific Features of the Michael Condensation in the Series of 3-R-3H-Furan-2-ones

The Michael condensation in the series of 5-aryl-3H-furan-2-ones with chalcones containing electron-donating substituents was studied. In the case of ,-unsaturated ketones containing an electrondonating substituent, the reaction does not stop at the stage of formation of 1,5-dicarbonyl compounds but is accompanied by intramolecular cyclodehydration yielding a new series of furo[2,3-b]-4H-pyrans. A mechanism of formation of these products was suggested. The structure of reaction products was proved by IR and ¹H NMR spectroscopy.     

Synthesis ofO-methyloximes and nitrones of a series of substituted 4-[2-hydroxy-2-(1H-1,2,4-triazol-1-ylmethyl)cyclohexylidenemethyl]-benzaldehydes and their fungicidal activity

O-Methyloximes and nitrones of a series of substituted 4-[2-hydroxy-2-(1H-1,2,4-triazol-1-ylmethyl)cyclohexylidenemethyl]benzaldehydes have been synthesized, and their fungicidal activity has been assayed. All of them exhibit low fungicidal activity in thein vitro assays and high activity in thein vivo assays; theO-methyl oximes are more active than the corresponding nitrones.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2082–2087, December, 1993.     

Lipophilic extracts in phytotherapy and phytocosmetics: Production and biological properties

This review considers methods of obtaining lipophilic extracts from plant raw material, and their composition, biological properties, and use in phytotherapy and phytocosmetics.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 240 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 437–448, July–August, 1998.     

UV-spektrographische Untersuchungen an Derivaten des 1,8-Naphthyridins

Zusammenfassung Es werden die Absorptionsspektren von sechs Derivaten des 1,8-Naphthyridins und ihre Abhängigkeit vom pH-Wert des Lösungsmittels besprochen. Die vermutlichen Gründe hierfür werden diskutiert. Weiters wird auf Zusammenhänge mit den Spektren des Naphthalins und Chinolins hingewiesen.Mit 7 Abbildungen     

Synthesis and electrical conductivity of poly(arylene vinylene). I. Poly(2,5-dimethoxyphenylene vinylene) and poly(2,5-dimethylphenylene vinylene)

The highly conjugated aromatic polymers, poly(2,5-dimethoxyphenylene vinylene) and poly(2,5-dimethylphenylene vinylene), were obtained from their water soluble, sulfonium salt precursor polymers. Films of these polymers were reacted with either AsF₅ or I₂ vapor. Poly(2,5-dimethoxyphenylene vinylene) showed increases in electrical conductivity of up to 14 to 15 orders of magnitude for these two dopants, while an 8 to 9 order of magnitude increase was observed for poly(2,5-dimethylphenylene vinylene) with the same dopants. The synthesis of the precursor polymers, the properties and elimination reactions of films of the precursors, the doping reactions, and the conductivities of the resulting phenylene vinylene films are discussed.     

Magic numbers of large rare gas clusters

The superior stability of closed-shell icosahedral structures is evident from size distributions of argon, krypton and xenon cluster ions in the size range 100?n?1000.     

Rapid determination of protein in plant material by flow injection spectrophotometry with trinitrobenzenesulfonic acid

The rapid determination of protein in plant material based on spectrophotometric determination of amino acids in protein hydrolysates with trinitrobenzenesulfonic acid has been adapted to flow injection analysis. With the manifold described, a routine sampling rate of 120 samples/h is possible, though this, as well as sensitivity, can easily be varied. The method was calibrated against the Kjeldahl method and a good correlation was obtained between the two methods over a wide range of protein values for beans.     

The photoelectron spectrum of tetramethyldiazetine: The elucidation of ring size effects on azo group ionization potentials

The photoelectron spectrum of 3,3,4,4-tetramethyldiazetine (4-Me₄) has been measured. By comparison with the previously reported photoelectron spectra of 3,3-dimethyldiazirine and 3,3,5,5-tetramethylpyrazoline, 4-Me₄ has three resolved low energy ionization (8.87, 10.36, and 11.65 eV) with an anomalously low second ionization potential. MINDO/3-and ab initio STO-3G calculations on 3-, 4-, and 5-membered ring azo compounds (diazenes) have been carried out, and these allow definite conclusions about the order of n_?, n₊, and π ionization potentials to be made for the diazetine (n_? < N₊ < π) and for 3,3-dimethyldiazirine and 3,3,5,5-tetramethylpyrazoline(n_? < π n₊), in agreement with the predictions of Heilbronner. Ab initio STO-3G calculations on the nitrogen and alkyl fragments of the cyclic diazenes reveal the origin of ionization energy shifts with changes in ring size.