Dmitry G. Beresnev

Direct Modification of Benzoannelated Crown Ethers with 1,2,4-Triazin-5(2H)-one Moieties

A convenient method for one-step coupling of benzoannelated crown ethers with 1,2,4-triazinones based on the reaction of nucleophilic addition to unsubstituted carbon atom of the triazine ring has been worked out. It has been shown that the reaction of 3-substituted 1,2,4-triazin-5(2H)-ones (1) with benzocrown ethers (benzo-12-crown-4, benzo-15-crown-5, benzo-18-crown-6) in the presence of acetic or trifluoroacetic anhydride is accompanied by acylation of triazine ring and results in formation of 3-(1-acyl-5-oxo-1,4,5,6-tetrahydro-1,2,4-triazin-6-yl)benzocrown ethers (7-12). The latters were converted to 3-(5-oxo-2,5-dihydro-1,2,4-triazin-6-yl)benzocrown ethers (18-20) using two alternative routes: the elimination of acetic or trifluoroacetaldehyde or the deacylation followed by the oxidation of the 1,4,5,6-tetrahydro derivatives (13-15).

Direct C-C Coupling of meso-Octamethylcalix[4]pyrrole with 6-Nitroazolopyrimidines

It has been found that the reaction of meso-octamethylcalix[4]pyrrole with four equivalents of 6-nitroazolopyrimidine is accompanied by the C-C coupling of unsubstituted carbon atom in azines with P-position of pyrrole rings and results in the formation of tetrapyrimidine-substituted calix[4]pyrroles without introduction of any catalysts. Mono- and di-substituted calixpyrroles have been isolated.

Modification of macrocyclic compounds by azaheterocycles

Synthesis, modification and properties of macrocycles, such as crown ethers, their open-chain analogues, i.e. podands, calixarenes and resorcinarenes, having azaheterocyclic fragment are discussed.

SNII - REACTIONS OF 1,2,4-TRIAZINE DERIVATIVES WITH ACETOPHENONES

SN-products were obtained by the reaction of azoloannelated 1,2,4-triazines and 3-substituted 1,2,4-triazin5(2H)-ones with acetophenones. The reasons of extraordinary readily aromatization of a-adducts have been discussed. Introduction. It has been known that most approaches used for functionalization of 1,2,4-triazines and their azoloannelated analogues are based on the reaction of nucleophilic substitution of good leaving groups (1). However, according to the modern conceptions of nucleophilic substitution in aromatic systems the nucleophilic attack first of all takes place at the unsubstituted carbon atom of triazine ring even if good leaving group is in the cycle. o-Adducts obtained by interaction of aza-aromatic compounds with nucleophiles can undergo dissociation or take part in the further transformations, such as aromatization by oxidizing or awfo-aromatization (SN-processes), ring opening or recyclization. As a rule the o-adducts obtained from 1,2,4-triazines are stable compounds. The main difficulty of realizing SN-process consists in the aromatization of o-adducts (2). Discussion. In present work the extraordinary readily oxidation of o-intermediates obtained by the reaction of 1,2,4triazines (azoloannelated 1,2,4-triazines 1_,2 and l,2,4-triazin-5(2H)-ones 8-10) with acetophenones 3a-c has been found. Thus, such a-adducts 4,5 a-c were oxidized very readily by the action of oxygen contained in a solvent and in

The first example of direct heterylation of calixpyrrole

Abstract1,2,4-Triazine derivatives react with calixpyrrole to give stable nucleophilic addition products.

New 1,2,4-triazine-containing podands: synthesis and properties

A method of one-step C-C coupling of 1,5-bis(2,6-dimethylphenoxy)-3-oxapentane (1a) and 1,8-bis(2,6-dimethylphenoxy)-3,6-dioxaoctane (1b) with 3-methylthio- (2) and 3-amino-1,2,4-triazine (3) and 3-aryl-1,2,4-triazin-5-one (6-8) has been described. The reaction of compounds 1a,b with compounds 2 and 3 in the presence of trifluoroacetic acid results in the addition of the dimethylphenoxy group to the unsubstituted C(5) carbon atom of the triazine ring. The reactions of triazinones 6-8 with compounds 1a,b in a mixture of trifluoroacetic acid and organic anhydrides are accompanied by the acylation of the nitrogen atom adjacent to the reaction center and affords bis[(3-R-1-acyl-5-oxo-1,4,5,6-tetrahydro-1,2,4-triazin-6-yl)-2,6-dimethylphenoxy]-3-oxapentane or -3,6-dioxaoctane. The obtained adducts can smoothly be oxidized under mild conditions to form more stable products of nucleophilic hydrogen substitution in the triazine ring. The extraction and transport of Ca2+ and Mg2+ cations through an organic membrane by the compounds synthesized are discussed.

The formation of 1,2,4-triazolylimidazolidine-2,4-diones in reactions of 3-aryl-1,2,4-triazin-5(2H)-ones with alkylureas

Recyclization of the addition products of alkylureas to 3-aryl-1,2,4-triazin-5(2H)-ones affording 1,2,4-triazole derivatives was found to occur in Ac2O.

SNH-Reactions of triazolo[4,3-b]- and tetrazolo[1,5-b]-1,2,4-triazines with methylene-active carbonyl compounds

Unsubstituted triazolo[4,3-b]- and tetrazolo[1,5-b]-1,2,4-triazines react with carbanions generated from dimedone and barbituric acid to give adducts of a C-nucleophile with the heterocyclic system through the C=N double bond. The adducts can be oxidized under mild conditions into products of nucleophilic hydrogen substitution. Analogous adducts with carbanions produced in the reactions of ethyl cyanoacetate and ethyl malonate with ButOK proved to be unstable; in this case, the title azolotriazines immediately yield products of nucleophilic hydrogen substitution in position 7. Tautomerism of the SNH products obtained is discussed.

Direct introduction of heterocyclic units into porphyrin derivatives

In the reaction with quinazoline and 5-phenyl-1,2,4-triazin-5(2H)-one, 5,10,15,20-tetra(4-methoxyphenyl)porphyrin exhibits nucleophilic properties. In quinazoline excess, C—C coupling occurs at the C=N bond of azines and position 3 of the aryl ring to form 5,10,15,20-tetrakis(3-heteryl-4-methoxyphenyl)porphyrins. Monoheteryl-substituted porphyrin was obtained by the reaction of equimolar amounts of 5,10,15,20-tetra(4-methoxyphenyl)porphyrin and 5-phenyl-1,2,4-triazin-5(2H)-one.