Created are the sorbents based on Silica gel non-covolently modified with partially hydrogenated heterocyclic compounds (PHHC), containing nitrogen as donor atoms for purification of aqueous media from technogenic contaminants. The investigations show that the modified silica gel is characterized by a sorption capacity relatively higher than that of unmodified one. The sorption degree of metal ions is studied depending on their concentrations, total mineralization and pH value of the solutions. Conditions for selective sorption of microquantities of Eu3+ which has been used as chemically identical to Am-241 are described. Moreover it was shown that PHHC-modified silica gel was potential to use as the sorbent to concentrate the Eu3+ and Sr2+ metal ions with :initial concentrations near 1 mg.L-1 for the quantitative analysis. Also the possible mechanism of metal ion sorption on the developed sorbents was proposed.

We have studied the reactions of 3-amino, 3,5-diamino-, and 3-amino-5-trifluoromethyl-1,2,4-triazole with esters of substituted cinnamic acids and aromatic unsaturated ketones; we have established the directionality of formation of the tetrahydrooxopyrimidine ring. We have carried out hydrolysis and hydrazinolysis of 7-phenyl-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]pyrimidin-5-one. We have conducted an X-ray diffraction study of isopropylidene hydrazide of 3-(5-amino-1,2,4-triazol-1-yl)-3-phenylpropionic acid.

Novel simple, efficient, and eco-friendly synthetic procedure for preparation of pyrazolo[3,4-b]quinolin-5-ones based on three-component microwaves-assisted heterocyclization reaction of 5-aminopyrazoles, aromatic aldehydes, and dimedone in hot-water medium was developed. The new method allows obtaining target heterocycles in good and excellent yields and with high degree of purity. J. Heterocyclic Chem., (2011).

The synthesis of new amino and alkoxy derivatives of thiazole-5-carbaldehyde, on the basis of which α,β-unsaturated ketones of the thiazole series were synthesized, are described in this paper. The possibility of obtaining chalcones and variation of substitution reactions in the thiazole ring has been shown.

An efficient method for the synthesis of novel 3-(1,3-thiazol-2-yl)-7,8-dihydroquinoline-2,5(1H,6H)-diones from various 2-dimethylaminomethylidenecyclohexane-1,3-diones, (1,3-thiazol-2-yl)acetonitriles, and dimethylformamide dimethyl acetal was developed. These transformations proceeded through intermediate 2-[2-(4-aryl-1,3-thiazol-2-yl)-2-cyanoethenyl]-3-oxocyclohex-1-en-1-olates. They were isolated as piperidinium salts and used in further heterocyclization reactions with aromatic amines, giving novel 1-aryl-3-(1,3-thiazol-2-yl)-7,8-dihydroquinoline-2,5(1H,6H)-diones. These compounds were also obtained by preparative three-step “one pot” synthesis under controlled microwave irradiation.

Regio- and chemoselective multicomponent protocols for the synthesis of 1,4,6,7,8,9-hexahydro-1H-pyrazolo[3,4-b]quinolin-5-ones, 5,6,7,9-tetrahydropyrazolo[5,1-b]quinazolin-8-ones, and 5a-hydroxy-4,5,5a,6,7,8-hexahydropyrazolo[4,3-c]quinolizin-9-ones starting from 5-amino-3-phenylpyrazole, cyclic 1,3-dicarbonyl compounds and aromatic aldehydes are described. Whereas the three-component coupling in ethanol under reflux conditions provides mixtures of pyrazoloquinolinones and pyrazoloquinazolinones, the condensation can be successfully tuned toward the formation pyrazoloquinolinones (Hantzsch-type dihydropyridines) by performing the reaction at 150 degrees C in the presence of triethylamine base applying sealed vessel microwave or conventional heating. On the other hand, using sonication at room temperature under neutral conditions favors the formation of the isomeric pyrazoloquinazolinones (Biginelli-type dihydropyrimidines). These products are also obtained when the three-component condensation is executed in the presence of trimethylsilylchloride as reaction mediator at high temperatures. A third reaction pathway leading to pyrazoloquinolizinones in a ring-opening/recyclization sequence can be accessed by switching from triethylamine to a more nucleophilic base such as sodium ethoxide or potassium tert-butoxide. The reaction mechanism and intermediates leading to these three distinct tricyclic condensation products are discussed.

The reactions of 3-substituted 5-aminopyrazoles with arylidenepyruvic acids and their synthetic precursors, pyruvic acid and aromatic aldehydes, were studied. Several different reaction pathways for these cyclocondensation reactions were established depending on the reaction conditions and building block selection. The formation of pyrazolo[3,4-b]pyridine-6-carboxylic acids as major products and related compounds was discussed from the mechanistic point of view.

The present work is devoted to the investigation of 2,4,6-triaryl-1,2,5,6-tetrahydropyrimidine derivatives. A new facile approach to their synthesis based on the reaction of α,β-unsaturated ketones, carbonyl compounds and ammonia was developed. Some stereochemical features of the compounds obtained were fixed on the base of NMR data (including COSY and NOESY experiments).

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Substituted 1,10b-dihydro-5H-pyrazolo[1,5-c] 1,3-benzoxazines have been obtained by condensation of 5-(2-hydroxyphenyl)-3-phenylpyrazole with aromatic aldehydes. The detailed structure of the compounds obtained has been elucidated from their1H NMR spectra by application of the nuclear Overhauser effect and the conclusions have been confirmed by an X-ray diffraction study.

The bond lengths in the five-membered ring of the title compound, C3H3F3N4, (1) are equal within three standard deviations to those in 5-amino-3-nitro-1H-1,2,4-triazole. The amino group in 1) has a trigonal-pyramidal configuration. Molecules of (1) form layers in the ab plane via intermolecular hydrogen bonds of the type N-H ... N.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.