Synthesis of isoxazolines from nitrile N-oxides generated from nitroalkenes

In this review, information on the production of isoxazolines and condensed isoxazoline systems by the intramolecular 1,3-bipolar cycloaddition of unsaturated nitrile N-oxides generated in situ from nonconjugated nitroalkenes is generalized and systematized. The isoxazoline derivatives formed as the result of these reactions are promising synthons in the synthesis of various natural compounds and their analogues.Krakow Polytechnic Institute, Poland. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 291–305, May–August, 1992.     

Acetylenic thiophenes from the roots of Escinops ellenbeckii from Ethiopia

The hexane fraction from the roots of Echinops ellenbeckii O. Hoffm. from Ethiopia yielded seven acetylenic thiophenes of which five compounds (1, 3, 4, 6, 7) are reported for the first time in this species: the monothiophenes 5-(penta-1,3-diynyl)-2-(but-3-en-1-ynyl)-thiophene (1), 5-(penta-1,3-diynyl)-2-(4-acetoxy-but-1-ynyl)-thiophene (2), 5-(penta-1,3-diynyl)-2-(3-hydroxy-4-acetoxy-but-1-ynyl)-thiophene (3), 5-(penta-1,3-diynyl)-2-(3,4-diacetoxy-but-1-ynyl)-thiophene (4), 5-(penta-1,3-diynyl)-2-(3-chloro-4-acetoxy-but-1-ynyl)-thiophene (5), 5-(penta-1,3-diynyl)-2-(3,4-epoxy-but-1-ynyl)-thiophene (6) and the dithiophene 5-[(5-acetoxymethyl-2-thienyl)-2-(but-3-en-1-ynyl)]-thiophene (7). Additionally, four fatty acids (C14, C15, C16 and C18), seven fatty acid esters and three long-chain hydrocarbons could be identified. All the structures were elucidated on the basis of spectral data by GC-MS, HRMS and the NMR techniques.     

Precipitation from homogeneous solution of cations released from ETDA complexes

The suitability of EDTA complexes for use in precipitation of certain cations from homogeneous solution under various experimental conditions can be predicted from a knowledge of the solubility product of the compound to be precipitated and the complex stability constant. A brief review of previous work in the field of masking effectiveness is given. An examination of factors influencing precipitation has been carried out. It is shown that a simple ratio can be used for predicting the likelihood of precipitation at various pH values and that more rigorous theoretical approaches are not necessarily more advantageous.     

Products from dehydration of dicarboxylic acids derived from anthranilic acid

Treatment of N-(carboxymethyl)-anthranilic acids 1 with several dehydrating agents, gave the cyclic ortho amides 6, or the 7-membered anhydrides 7. After reaction of N-(carboxymethyl)-anthranilic acid (1a) with acetic anhydride, a diacetylated fused diketopiperazine indole dimer (18) could be isolated. Dehydrations of 2,2'-iminobis-benzoic acid led to the corresponding cyclic ortho amides 23. The dynamic behaviour of some of these compounds, and their precursors, was studied.     

Electrochemical deposition of platinoids from ammonia-nitrate eluates from silver refining

The differences in the electrochemical behavior of palladium and platinum in the individual and mixed ammonia-nitrate eluates from silver refining, insufficient for selective electrowinning of palladium, were revealed and studied. The possibility of obtaining the binary alloys of metals from the platinum group was shown. A method for the preparation of platinized titanium anodes by platinum electrodeposition on the titanium cathodes from palladium-depleted electrolytes of refining at OAO Uralelektromed’ was suggested.     

利用盐酸法钛白废液制备铁黄颜料研究

氧化铁黄又称羟基铁,简称铁黄,化学式为α-FeOOH,具有良好的耐光性、耐大气性和耐碱性。较其他黄色颜料的遮盖力高,着色力也强。广泛地用于橡胶制品、油漆、塑料、油墨、药片糖衣等的着色,也是人造大理石、水磨石地面、铺路砖、墙面粉饰等的着色剂[1]。四川省自贡市金红石厂以3     

Synthesis of substituted dihydroisocarbostyrils from 5-hydroxyamides obtained from dilithio-N-substituted o-toluamides

δ-Hydroxyamides, prepared by condensation of ketones or aldehydes at the 2-methyl group of Nsubstituted o-toluamides by means of n-butyllithium, were cyclodehydrated with sulfuric acid to form 2,3-disubstituted and 2,3,3-trisubstituted 3,4-dihydroisocarbostyriIs. Also, δ-hydroxyamides obtained from condensation of ketones at the 2-benzyl group of N-methyl-o-benzylbenzamide, were cyclodehydrated to give 2,3,3,4-tetrasubstituted 3,4-dihydroisocarbo-styrils. All of the products appeared to be new. This new method, which involves an unusual acid catalyzed cyclodehydration, is convenient and apparently quite general.     

Synthesis of functionalized pentacenes from isobenzofurans derived from C-H bond activation

The synthesis of unsymmetric functionalized pentacenes from 1,4-anthraquinones and functionalized isobenzofurans, which were prepared by transformation via C-H bond activation, was successfully accomplished. Examples of the synthesis of pentacenes with functional groups at the 5-position are still rare. These obtained functionalized pentacenes are highly soluble in hexane, toluene, and THF.     

Syntheses of 1,5-dideoxy-1,5-imino-D-mannitol from D-mannose and from D-glucose

Unambiguous enantiospecific syntheses of 1,5-dideoxy-1,5-imino-D-mannitol (LU1, 1-deoxy-mannojirimycin) are reported (i) from D-mannose via hydrogenation of a 5-azido-5-deoxy mannose, and (ii) from D-glucose, in which the key step involves nucleophilic substitution of a trifluoromethanesulphonyl group from C-2 of D-glucose.     

Oxygen transfer from sulfoxide: formation of aromatic aldehydes from dihalomethylarenes

The conversion of dihalomethylarenes to the corresponding aldehydes is accomplished conveniently by using sulfoxides as the oxygen donor under neutral conditions.     

Polymers from intermediates obtained from hydrogen cyanide

The recent demonstration of an easy synthesis of diiminosuccinonitrile (DISN) from hydrogen cyanide and cyanogen, the reduction of DISN to diaminomaleonitrile (DAMN), and the use of these compounds to form difunctional heterocycles has made several new polyamide intermediates accessible. The 1- and 2-methyl-1,2,3-triazole-4,5-dicarbonyl chlorides have been polymerized interfacially to form high-melting polyamides of good heat stability. Interfacial polymerization of 1-methylimidazole-4,5-dicarbonyl chloride and trans-2,5-dimethylpiperazine has given a polyamide that is water-soluble. The 2,6- and 2,3-pyrazinedicarbonyl chlorides have been similarly converted to high-melting polyamides. 2,6-Dicyano-3,5-dipiperazinylpyrazine has been prepared from tetracyanopyrazine and piperazine and reacted with toluene diisocyanate to form a strong, stiff polyurea. Polyamides were also made from 2,3-diaminoquinoxaline, 1,4,5,6-tetrahydro-5,6-dioxo-2,3-pyrazinedicarbonitrile, and DAMN.     

Essential oil from aerial parts of of Betonica grandiflora Willd. from Iran

The chemical composition of the essential oil obtained from the aerial parts of Betonica grandiflora Willd., growing wild in Iran, was analysed by gas chromatography-mass spectrometry for the first time. Overall, 40 volatile components were identified on the basis of their mass spectra characteristics and retention indices in which ledol (21.8%), myrtenyl acetate (21.7%), eudesm-7(11)-en-4-ol (6.5%), trans-caryophyllene (5.5%), α-bisabolol (4.9%) and isolongifolol (4.5%) were the major constituents. Oxygenated sesquiterpenes, monoterpene hydrocarbons and sesquiterpene hydrocarbons were the main groups of compounds with 45.6%, 23.1% and 18.4%, respectively. The oil was moderately active against Bacillus subtilis and Staphylococcus aureus and inactive against Enterococcus faecalis and Klebsiella pneumoniae.     

Constituents of the essential oil from aerial parts of Chromolaena odorata from Thailand

The chemical composition of the essential oil from the aerial parts of Chromolaena odorata, collected from Phitsanulok, Thailand was analyzed by means of GC-(FID) and GC-MS. Twenty-two constituents were identified. The major components were pregeijerene (17.6%), germacrene D (11.1%), alpha-pinene (8.4%), beta-caryophyllene (7.3%), vestitenone (6.5%), beta-pinene (5.6%), delta-cadinene (4.9%), geijerene (3.1%), bulnesol (2.9%), and trans-ocimene (2.2%).     

Comparative Analysis of Proteins from Cytoplasmatic Organelles of Pollen from Certain Cotton Species

The protein composition of cytoplasmatic organelles within species, phylogenetic group, and genus was investigated using electrophoretic separation of protein fractions.