Latvian Institute of Organic Chemistry

Riga, Latvia

Latvian Institute of Organic Chemistry

Riga, Latvia
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Batenko N.,Riga Technical University | Belyakov S.,Riga Technical University | Belyakov S.,Latvian Institute of Organic Chemistry | Kiselovs G.,Latvian Institute of Organic Chemistry | Valters R.,Riga Technical University
Tetrahedron Letters | Year: 2013

Novel 6,7-dichloropyrido[1,2-a]benzimidazole-8,9-dione derivatives and its analogues were synthesized directly from chloranil and different 2-amino(di)azines without using a catalyst or activation. Further nucleophilic substitution reactions were carried out. © 2013 Elsevier Ltd. All rights reserved.


Batenko N.,Riga Technical University | Neibolte I.,Riga Technical University | Belyakov S.,Riga Technical University | Belyakov S.,Latvian Institute of Organic Chemistry | Valters R.,Riga Technical University
Journal of Fluorescence | Year: 2016

This communication concerns the synthesis, structural characterization and fluorescent properties of novel naphtho[2,3-b]indolizine-6,11-dione derivatives. The target compound synthesized by one-pot multicomponent reaction between naphthoquinone, indandione and pyridine derivatives. The structures of synthesized compounds were characterized by IR, 1H NMR and 13C NMR analysis. The structure of two compounds was confirmed by single crystal X-ray diffraction. The photophysical properties of synthesized compounds were measured in a variety of organic solvents. The effects of substituents and solvents on UV-vis spectra and fluorescence emission were analyzed. All compounds were showed negative solvatochromism. The fluorescence emission of these derivatives was sensitive to solvent basicity and the large Stokes shifts (up to 129 nm, 4599 cm-1) were observed. The similar multicomponent reaction between naphthoquinone, bindone and pyridine derivatives provide the formation of stable non-fluorescent compound possessing zwitter-ionic structure. © 2015 Springer Science+Business Media New York.


Vorona M.,Latvian Institute of Organic Chemistry | Veinberg G.,Latvian Institute of Organic Chemistry | Vikainis S.,Latvian Institute of Organic Chemistry | Kuznetsov E.,Latvian Institute of Organic Chemistry | And 5 more authors.
Chemistry of Heterocyclic Compounds | Year: 2012

Two novel methods have been developed for the preparation of 2-[(4 R)-2-oxo-4-phenylpyrrolidin-1-yl]acetamide ((R)-Phenotropil). In the first, n-butyl (3 R)-4-amino-3-phenylbutyrate is alkylated with haloacetamide in DMF in the presence of potassium phosphate monohydrate, and the intermediate 4-carbamoylmethylamino-3-phenylbutyrate is subsequently cyclized by refluxing in toluene in the presence of potassium phosphate monohydrate and tetrabutylammonium bromide. In the second, chloroacetonitrile is used under similar conditions in place of the haloacetamide. Both methods lead to (R)-Phenotropil in 40-60% yields calculated on the starting n-butyl (3 R)-4-amino-3-phenylbutyrate. © 2012 Springer Science+Business Media, Inc.


Vorona M.,Latvian Institute of Organic Chemistry | Veinberg G.,Latvian Institute of Organic Chemistry | Vikainis S.,Latvian Institute of Organic Chemistry | Kuznetsov E.,Latvian Institute of Organic Chemistry | And 4 more authors.
Chemistry of Heterocyclic Compounds | Year: 2012

Two novel methods have been developed for the preparation of 2-[(4R)-2-oxo-4-phenylpyrrolidin-1-yl]acetamide ((R)-Phenotropil). In the first, n-butyl (3R)-4-amino-3-phenylbutyrate is alkylated with haloacetamide in DMF in the presence of potassium phosphate monohydrate, and the intermediate 4-carbamoylmethylamino-3-phenylbutyrate is subsequently cyclized by refluxing in toluene in the presence of potassium phosphate monohydrate and tetrabutylammonium bromide. In the second, chloroacetonitrile is used under similar conditions in place of the haloacetamide. Both methods lead to (R)-Phenotropil in 40-60% yields calculated on the starting n-butyl (3R)-4-amino-3-phenylbutyrate. © 2012 Springer Science+Business Media, Inc.


Arsenyan P.,Latvian Institute of Organic Chemistry | Vasiljeva J.,Latvian Institute of Organic Chemistry | Belyakov S.,Latvian Institute of Organic Chemistry
Chemistry of Heterocyclic Compounds | Year: 2011

A two-stage method has been developed for the synthesis of the methyl ester of 3-bromo-2-(2-hydroxy-2-propyl)-7-oxo-7H-selenolo[2,3-f]chromene-8-carboxylic acid - a new example of a class of selenophene-containing polycyclic heterocycles. The molecular structure was confirmed by X-ray crystallography. © 2011 Springer Science+Business Media, Inc.

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