N. V. Yashin

Complexes of hypervalent iodine compounds with nitrogen ligands

The stable 1:1 complexes of benziodoxole with heterocyclic amines were prepared by a reaction of 1-hydroxy-1H-1λ3-benzo[d][1,2]iodoxol-3-one with trimethylsilyl triflate and pyridine or 1,1′-sulfonyldiimidazole. The structure of these complexes was confirmed by spectroscopic data and a high resolution ES mass-spectrometry. A novel pentavalent iodine complex with a chelating, polydentate nitrogen ligand was prepared from bis(acetoxy)iodylbenzene, trimethylsilyl triflate, and 2,2′-bipyridyl.

Synthesis of amino acids of cyclopropylglycine series

The review covers methods of synthesis of amino acids of the cyclopropylglycine series published in the past decade. Main methods of synthesis of cyclopropylglycines are based on the carbene and ylide addition to alkenes, enzymatic reactions, the Kulinkovich cyclopropanation of esters and amides, MIRC reactions, the modification of cyclopropanecarbaldehydes by the Strecker reaction, and other transformations of functional groups of cyclopropanes. Particular attention is given to 2-carboxycyclopropylglycines and 3,4-methanoprolines. These compounds have attracted interest as conformationally rigid cyclopropane-containing analogs of glutamic acid and proline and also as components of physiologically active peptides. The physiological properties of cyclopropylglycines are briefly characterized.

Synthesis of nitrosubstituted triangulanes

The [1+2] cycloaddition of ethyl nitrodiazoacetate to various methylenecyclopropanes afforded 1-ethoxycarbonyl-1-nitropolyspirocyclopropanes. These compounds were used in the synthesis of first representatives of nitrosubstituted triangulanes. Nitrospiropentane was prepared also by dehydrohalogenation of 1-bromomethyl-1-(nitromethyl)cyclopropane.

Synthesis of novel non-natural conformationally restricted cyclopropane amino acids of spirane series

New conformationally rigid spirane analogues of γ-aminobutyric acid, namely, 4-aminospiro[2.2]pentanecarboxylic and 1-aminospiro[2.3]hexane-5-carboxylic acids were synthesized from the corresponding 4and 5-methoxycarbonyl-1-nitrospiro[2.n]alkane-1-carboxylic esters obtained in turn by the [1+2] cycloaddition of ethyl nitrodiazoacetate to methylidenecycloalkanecarboxylic esters.

Synthesis of conformationally restricted Analogs of γ-aminobutyric acid

Data on methods of the synthesis of conformationally restricted analogs of γ-aminobutyric acid (GABA) are systematized in the review. Approaches to the synthesis of different types of conformationally restricted GABA analogs are presented: γ-aminobutenoic acids, aminocycloalkanecarboxylic acids, carboxy-substituted azetidines, prolines, amino acids containing aromatic (heterocyclic including) fragments.

The standard enthalpies of formation of nitro compounds with small rings

The energies of combustion and standard enthalpies of formation of 1-nitrospiro[2.3]hexane, 7-nitrodispiro[3.0.3.1]nonane, and 1,1-dinitrocyclopropane were determined experimentally.

Oxidative nucleophilic substitution reaction of alkyl iodides upon treatment with perchlorate and dinitramide anions. Synthesis of alkyl-substituted perchlorates

Reactions of oxidative nucleophilic substitution of alkyl iodides with lithium perchlorate and dinitramide were studied. The reactions of alkyl iodides and lithium perchlorate, proceeding in the presence of nitronium tetrafluoroborate as an oxidant, furnished a series of new alkyl perchlorates, including those containing an adamantyl fragment. Spectral properties of alkyl perchlorates were studied in detail for the first time. The reactions of oxidative nucleophilic substitution of iodoacetic ester and lithium dinitramide, proceeding upon treatment with nitronium tetrafluoroborate or ozone, resulted in the substitution of an iodine atom with the nitrate anion.

Methods of synthesis and synthetic application of α-diazomethylphosphonates

Data on methods of synthesis and reactivity of α-diazomethylphosphonic acid esters are classified. Main approaches to obtain diazomethylphosphonate ester (the Seyferth—Gilbert reagent) as well as α-substituted diazomethylphosphonates are considered. The most important reactions of α-diazomethylphosphonates are discussed: [1+2] cycloaddition to alkenes, insertion into heteroatom—heteroatom bonds, reactions with aldehydes and ketones, being of interest as preparative methods to obtain cyclopropane phosphonates, α-substituted methylphosphonic esters and alkynes, correspondingly.

The Standard Enthalpies of Formation of 1-Nitrodispiro(2.0.2.1)heptane and 1-Nitrodispiro(2.0.3.1)octane

The energies of combustion and standard enthalpies of formation of 1-nitrodispiro[2.0.2.1]heptane and 1-nitrodispiro[2.0.3.1]octane were determined experimentally.

Synthesis of novel non-natural spiro[2.3]hexane amino acids, the conformationally restricted analogs of γ-aminobutyric acid

Abstract3-Methylenecyclobutanecarboxylic acid and its methyl ester were used as the starting compounds for the synthesis of new spiro[2.3]hexane amino acids, the conformationally rigid analogs of γ-aminobutyric acid, namely, 5-aminospiro[2.3]hexanecarboxylic and 5-amino-spiro[2.3]hexanephosphonic acids, promising modulators of GABAergic cascades in the human central nervous system. The methods developed for the synthesis of the target amino acids are based on the reactions of catalytic [1+2] cycloaddition of diazoacetic and diazophosphonic esters to 3-substituted methylenecyclobutanes, as well as on a modified Curtius reaction for the transformation of a carboxy group to the amine one.