Anton Prokhorov - Academia.edu (original) (raw)
Papers by Anton Prokhorov
Tetrahedron Letters, Apr 1, 2009
The N-oxides of azines 1a–g react with lithium and/or potassium acetylides to give the correspond... more The N-oxides of azines 1a–g react with lithium and/or potassium acetylides to give the corresponding ethynylazines 2a–g. Reaction with lithium acetylide requires subsequent acylation of the intermediate anionic adduct for rearomatization whereas in the case of potassium acetylide, auto-aromatization takes place.
Chemistry of Heterocyclic Compounds, Nov 1, 2012
Information on the development of a valuable synthetic methodology based on inverse electron-dema... more Information on the development of a valuable synthetic methodology based on inverse electron-demand Diels–Alder reaction in the series of π-deficient azadienes (triazines and tetrazines) is summarized and classified. By this method it is possible to obtain mono-, di-, and triazines containing functional substituents both from the initial azine and from the dienophile. Such reactions are often the simplest and even the only possible method for the synthesis of substances with properties suitable for practical applications.
Journal of Organometallic Chemistry
Russian Chemical Bulletin, 2003
Nucleophilic substitution of hydrogen in pyrazine N-oxides under the action of CH-active compound... more Nucleophilic substitution of hydrogen in pyrazine N-oxides under the action of CH-active compounds requires activation with acylating agents. This activation facilitates aromatization of intermediate σH adducts via elimination of the acid residue to form substituted pyrazines. More electrophilic 1,2,4-triazine 4-oxides react with carbanions derived from CH-active compounds without additional activation according to a scheme, which has previously been unknown for azine N-oxides. This scheme involves aromatization of σH adducts through elimination of water by the E1cb mechanism. The reaction products occur in DMSO-d6 solutions predominantly as 6-methylene-1,6-dihydropyrazines and 5-methylene-4,5-dihydro-1,2,4-triazines.
Liquid Crystals, 2016
Herein, we report on a new series of mesomorphic compounds synthesised by directional functionali... more Herein, we report on a new series of mesomorphic compounds synthesised by directional functionalisation of 2,5-di(4-dodecoxyphen-1-yl-c-cyclopentene-pyridine) on the c-cyclopentene moiety. The first functionalisation of the starting compound gave rise to a racemic product modified with a hydroxyl group on the fused cyclopentene ring. Further oxidation of this alcohol to a prochiral ketone and subsequent enantioselective reduction back to the alcohol afforded a new chiral alcohol. Further, the hydroxyl group of the chiral alcohol could be substituted by fluorine in a S N 2 reaction, leading to a chiral compound with enantiomeric excess (ee) of 66% and chiral nematic liquid-crystalline (LC) phase.
ChemInform, 2005
Triazine derivatives R 0655 Regioselectivity of Nucleophilic Attack in the Reactions of 1,2,4-Tri... more Triazine derivatives R 0655 Regioselectivity of Nucleophilic Attack in the Reactions of 1,2,4-Triazine 4-Oxides with Certain C-Nucleophiles.-The reactions of 1,2,4-triazine 4-oxides (I) with C-nucleophiles under conditions of thermodynamic control occurs via nucleophilic attack at the position 3 of the heterocycle [→ (III) and (V)] whilst under conditions of kinetic control the position 5 is attacked [→ (VII)].
ChemInform, 2001
Auto-aromatization of the σ H-Adducts of 1,2,4-Triazine 4-Oxides with Carbanions in Reactions of ... more Auto-aromatization of the σ H-Adducts of 1,2,4-Triazine 4-Oxides with Carbanions in Reactions of Nucleophilic Substitution of Hydrogen.-Triazine 4-oxides (I) react with stable carbanions to furnish 5-substituted triazines (III) (9 examples) as products of a deoxidative nucleophilic substitution reaction.-(KOZHEVNIKOV, DMITRY N.; PROKHOROV, ANTON M.;
Progress in Heterocyclic Chemistry, 2014
Abstract This review covers the work published in the calendar year 2013. Novel reaction chemistr... more Abstract This review covers the work published in the calendar year 2013. Novel reaction chemistry and new ring synthetic methods for 1,2,3-triazines, 1,2,4-triazines, 1,3,5-triazines, and tetrazines are reviewed.
ChemInform, 2004
Addition of the Grignard reagents to 1,2,4-triazine 4-oxides followed by aromatization ofthe inte... more Addition of the Grignard reagents to 1,2,4-triazine 4-oxides followed by aromatization ofthe intermediate σ H -adducts by dehydrogenation or dehydration was used for synthesis of 5-alkyl- or 5-aryl-substituted 1,2,4-triazines and their 4-oxides.
ChemInform, 2004
Reactions of Pyrazine N-Oxides and 1,2,4-Triazine 4-Oxides with CH-Active Compounds.-The nucleoph... more Reactions of Pyrazine N-Oxides and 1,2,4-Triazine 4-Oxides with CH-Active Compounds.-The nucleophilic substitution of hydrogen in triazine N-oxides (V) with anionic nucleophiles usually proceeds with autoaromatization of the intermediate σ H adducts. Pyrazine N-oxides like (I), however, require activation by acylating agents to undergo this reaction.-(KOZHEVNIKOV, D. N.; KOVALEV, I. S.;
Tetrahedron Letters, 2000
Addition of hydroxylamine at the 3 position of 6-aryl-5-amino-1,2,4-triazine-4-oxides initiates t... more Addition of hydroxylamine at the 3 position of 6-aryl-5-amino-1,2,4-triazine-4-oxides initiates the amidine rearrangement resulting in 6-aryl-5-hydroxylamine-1,2,4-triazines, as con®rmed by an experiment with 15 N-labeling.
Tetrahedron Letters, 2012
Tetrahedron Letters, 2009
The N-oxides of azines 1a–g react with lithium and/or potassium acetylides to give the correspond... more The N-oxides of azines 1a–g react with lithium and/or potassium acetylides to give the corresponding ethynylazines 2a–g. Reaction with lithium acetylide requires subsequent acylation of the intermediate anionic adduct for rearomatization whereas in the case of potassium acetylide, auto-aromatization takes place.
Russian Chemical Bulletin, 2000
It was shown that cyanamide can successfully be used in reactions of nucleophilic substitution of... more It was shown that cyanamide can successfully be used in reactions of nucleophilic substitution of hydrogen with 1,2,4-triazin-4-oxides in the presence of a base to give 5-cyanoimino-1,2,4-triazines. It was found by13C NMR spectroscopy that these compounds and their alkylation products at the cyclic nitrogen atom exist in the form of 5-cyanoimino-2,5-dihydro-1,2,4-triazines.
Mendeleev Communications, 2000
Triazine 4-oxides react with stable carbanions to form 5-substituted 1,2,4-triazines as the produ... more Triazine 4-oxides react with stable carbanions to form 5-substituted 1,2,4-triazines as the products of deoxygenation nucleophilic substitution of hydrogen.
Chemistry of Heterocyclic Compounds, 2012
Information on the development of a valuable synthetic methodology based on inverse electron-dema... more Information on the development of a valuable synthetic methodology based on inverse electron-demand Diels–Alder reaction in the series of π-deficient azadienes (triazines and tetrazines) is summarized and classified. By this method it is possible to obtain mono-, di-, and triazines containing functional substituents both from the initial azine and from the dienophile. Such reactions are often the simplest and even the only possible method for the synthesis of substances with properties suitable for practical applications.
Chemistry of Heterocyclic Compounds, 2004
The addition of CH-active compounds to 6-aryl-1,2,4-triazine 4-oxide is reversible and occurs und... more The addition of CH-active compounds to 6-aryl-1,2,4-triazine 4-oxide is reversible and occurs under conditions of kinetic control at position 5 of the heterocycle to form cyclic C(5)-σ H adducts. Under conditions of thermodynamic control the nucleophilic attack is directed to position 3 of the heterocycle and is accompanied by its opening to form the more stable open chain addition products. Attack of ethylmagnesium bromide is directed exclusively to the 5 position of the 6-aryl-1,2,4-triazine 4-oxides as a result of the irreversibility of the given reaction.
Tetrahedron Letters, Apr 1, 2009
The N-oxides of azines 1a–g react with lithium and/or potassium acetylides to give the correspond... more The N-oxides of azines 1a–g react with lithium and/or potassium acetylides to give the corresponding ethynylazines 2a–g. Reaction with lithium acetylide requires subsequent acylation of the intermediate anionic adduct for rearomatization whereas in the case of potassium acetylide, auto-aromatization takes place.
Chemistry of Heterocyclic Compounds, Nov 1, 2012
Information on the development of a valuable synthetic methodology based on inverse electron-dema... more Information on the development of a valuable synthetic methodology based on inverse electron-demand Diels–Alder reaction in the series of π-deficient azadienes (triazines and tetrazines) is summarized and classified. By this method it is possible to obtain mono-, di-, and triazines containing functional substituents both from the initial azine and from the dienophile. Such reactions are often the simplest and even the only possible method for the synthesis of substances with properties suitable for practical applications.
Journal of Organometallic Chemistry
Russian Chemical Bulletin, 2003
Nucleophilic substitution of hydrogen in pyrazine N-oxides under the action of CH-active compound... more Nucleophilic substitution of hydrogen in pyrazine N-oxides under the action of CH-active compounds requires activation with acylating agents. This activation facilitates aromatization of intermediate σH adducts via elimination of the acid residue to form substituted pyrazines. More electrophilic 1,2,4-triazine 4-oxides react with carbanions derived from CH-active compounds without additional activation according to a scheme, which has previously been unknown for azine N-oxides. This scheme involves aromatization of σH adducts through elimination of water by the E1cb mechanism. The reaction products occur in DMSO-d6 solutions predominantly as 6-methylene-1,6-dihydropyrazines and 5-methylene-4,5-dihydro-1,2,4-triazines.
Liquid Crystals, 2016
Herein, we report on a new series of mesomorphic compounds synthesised by directional functionali... more Herein, we report on a new series of mesomorphic compounds synthesised by directional functionalisation of 2,5-di(4-dodecoxyphen-1-yl-c-cyclopentene-pyridine) on the c-cyclopentene moiety. The first functionalisation of the starting compound gave rise to a racemic product modified with a hydroxyl group on the fused cyclopentene ring. Further oxidation of this alcohol to a prochiral ketone and subsequent enantioselective reduction back to the alcohol afforded a new chiral alcohol. Further, the hydroxyl group of the chiral alcohol could be substituted by fluorine in a S N 2 reaction, leading to a chiral compound with enantiomeric excess (ee) of 66% and chiral nematic liquid-crystalline (LC) phase.
ChemInform, 2005
Triazine derivatives R 0655 Regioselectivity of Nucleophilic Attack in the Reactions of 1,2,4-Tri... more Triazine derivatives R 0655 Regioselectivity of Nucleophilic Attack in the Reactions of 1,2,4-Triazine 4-Oxides with Certain C-Nucleophiles.-The reactions of 1,2,4-triazine 4-oxides (I) with C-nucleophiles under conditions of thermodynamic control occurs via nucleophilic attack at the position 3 of the heterocycle [→ (III) and (V)] whilst under conditions of kinetic control the position 5 is attacked [→ (VII)].
ChemInform, 2001
Auto-aromatization of the σ H-Adducts of 1,2,4-Triazine 4-Oxides with Carbanions in Reactions of ... more Auto-aromatization of the σ H-Adducts of 1,2,4-Triazine 4-Oxides with Carbanions in Reactions of Nucleophilic Substitution of Hydrogen.-Triazine 4-oxides (I) react with stable carbanions to furnish 5-substituted triazines (III) (9 examples) as products of a deoxidative nucleophilic substitution reaction.-(KOZHEVNIKOV, DMITRY N.; PROKHOROV, ANTON M.;
Progress in Heterocyclic Chemistry, 2014
Abstract This review covers the work published in the calendar year 2013. Novel reaction chemistr... more Abstract This review covers the work published in the calendar year 2013. Novel reaction chemistry and new ring synthetic methods for 1,2,3-triazines, 1,2,4-triazines, 1,3,5-triazines, and tetrazines are reviewed.
ChemInform, 2004
Addition of the Grignard reagents to 1,2,4-triazine 4-oxides followed by aromatization ofthe inte... more Addition of the Grignard reagents to 1,2,4-triazine 4-oxides followed by aromatization ofthe intermediate σ H -adducts by dehydrogenation or dehydration was used for synthesis of 5-alkyl- or 5-aryl-substituted 1,2,4-triazines and their 4-oxides.
ChemInform, 2004
Reactions of Pyrazine N-Oxides and 1,2,4-Triazine 4-Oxides with CH-Active Compounds.-The nucleoph... more Reactions of Pyrazine N-Oxides and 1,2,4-Triazine 4-Oxides with CH-Active Compounds.-The nucleophilic substitution of hydrogen in triazine N-oxides (V) with anionic nucleophiles usually proceeds with autoaromatization of the intermediate σ H adducts. Pyrazine N-oxides like (I), however, require activation by acylating agents to undergo this reaction.-(KOZHEVNIKOV, D. N.; KOVALEV, I. S.;
Tetrahedron Letters, 2000
Addition of hydroxylamine at the 3 position of 6-aryl-5-amino-1,2,4-triazine-4-oxides initiates t... more Addition of hydroxylamine at the 3 position of 6-aryl-5-amino-1,2,4-triazine-4-oxides initiates the amidine rearrangement resulting in 6-aryl-5-hydroxylamine-1,2,4-triazines, as con®rmed by an experiment with 15 N-labeling.
Tetrahedron Letters, 2012
Tetrahedron Letters, 2009
The N-oxides of azines 1a–g react with lithium and/or potassium acetylides to give the correspond... more The N-oxides of azines 1a–g react with lithium and/or potassium acetylides to give the corresponding ethynylazines 2a–g. Reaction with lithium acetylide requires subsequent acylation of the intermediate anionic adduct for rearomatization whereas in the case of potassium acetylide, auto-aromatization takes place.
Russian Chemical Bulletin, 2000
It was shown that cyanamide can successfully be used in reactions of nucleophilic substitution of... more It was shown that cyanamide can successfully be used in reactions of nucleophilic substitution of hydrogen with 1,2,4-triazin-4-oxides in the presence of a base to give 5-cyanoimino-1,2,4-triazines. It was found by13C NMR spectroscopy that these compounds and their alkylation products at the cyclic nitrogen atom exist in the form of 5-cyanoimino-2,5-dihydro-1,2,4-triazines.
Mendeleev Communications, 2000
Triazine 4-oxides react with stable carbanions to form 5-substituted 1,2,4-triazines as the produ... more Triazine 4-oxides react with stable carbanions to form 5-substituted 1,2,4-triazines as the products of deoxygenation nucleophilic substitution of hydrogen.
Chemistry of Heterocyclic Compounds, 2012
Information on the development of a valuable synthetic methodology based on inverse electron-dema... more Information on the development of a valuable synthetic methodology based on inverse electron-demand Diels–Alder reaction in the series of π-deficient azadienes (triazines and tetrazines) is summarized and classified. By this method it is possible to obtain mono-, di-, and triazines containing functional substituents both from the initial azine and from the dienophile. Such reactions are often the simplest and even the only possible method for the synthesis of substances with properties suitable for practical applications.
Chemistry of Heterocyclic Compounds, 2004
The addition of CH-active compounds to 6-aryl-1,2,4-triazine 4-oxide is reversible and occurs und... more The addition of CH-active compounds to 6-aryl-1,2,4-triazine 4-oxide is reversible and occurs under conditions of kinetic control at position 5 of the heterocycle to form cyclic C(5)-σ H adducts. Under conditions of thermodynamic control the nucleophilic attack is directed to position 3 of the heterocycle and is accompanied by its opening to form the more stable open chain addition products. Attack of ethylmagnesium bromide is directed exclusively to the 5 position of the 6-aryl-1,2,4-triazine 4-oxides as a result of the irreversibility of the given reaction.