L. A. Sviridova

Synthesis of hydroxyisoxazolidines on adsorbents

Abstract 3- And 5-hydroxyisoxazolidines can be synthesized in solution and on the surface of an adsorbent. The regioselectivity depends on the type of adsorbent used.

Synthesis of isoxazolidine derivatives from N-substituted hydroxylamines and α,Β-unsaturated ketones

The reaction of methyl vinyl ketone with N-Phenyl-hydroxylamine leads to a tautomeric mixture of 5-hydroxy-2-phenyl-5-methylisoxazolidine and its linear form, while the reaction with benzohydroxamic acid leads to linear products of addition to the oxygen or nitrogen atoms, depending on the reaction conditions. The first representatives of 5-hydroxyisoxazolidines with the residue of an aliphatic carboxylic acid attached to the nitrogen atom were obtained by acylation of 5-hydroxy-3,3,5-trimethylisoxazolidine.

Electrophilic substitution reactions of acylated 2-aminoindole derivatives

The bromination, nitration, and acylation reactions of various acyl derivatives belonging to the 2-aminoindole series of compounds have been investigated. It has been found that substitution occurs both at the β-carbon atom as well as at the 5- and 6-positions of the benzene ring. The ratio of reaction products depends upon the nature of the electrophile as well as on the degree of substitution of the 2-aminoindole.

Pharmacological Activity of 4,5-Dihydropyrazole Derivatives (Review)

The various types of pharmacological activity of 4,5-dihydropyrazole derivatives are reviewed. Attention is focused on the influence of various substituents in the dihydropyrazole core on the pharmacological effects of these compounds.

Bromination of 3-acyl-2-aminoindoles

Unlike 3-acylindoles, 3-acyl-2-aminoindoles display high selectivity on being electrophilically attacked in the benzene ring, and are substituted at the 6-position. At the same time, an unco-subsitution of the acyl group takes place (to the greatest extent — the formyl group). Direct bromination of 3-acyl- and 3-cyano-2-aminoindoles provides the 6-bromo- and 6,4-dibromo-2-aminoindoles and their derivatives.

Synthesis and structure of hydroxyisoxazolidines and derivatives of hydroxylamine and alkenals

The reactions of N-substituted hydroxylamines with alkenals serve as a method for the synthesis of the corresponding 2-substituted 3(5)-hydroxyisoxazolidines. The reaction pathway is determined by the nature of the substituent attached to the nitrogen atom. Ring-chain isomerism has been detected in these newly obtained compounds

Synthesis 5-(pyrazolin-3-ylmethylidene)-2-thiohydantoins and 2-alkylsulfanyl-5-(pyrazolin-3-ylmethylidene)-3,5-dihydro-4 H -imidazol-4-ones

A reaction of 3-allyl- and 3-phenylthiohydantoins with 1,5-diphenyl- and 1-phenyl-substituted 3-formyl-2-pyrazolines was used to obtain a series of 5-(pyrazolin-3-ylmethylidene)-2-thioxotetrahydro-4H-imidazol-4-ones, the subsequent alkylation of which with methyl iodide or ethyl chloroacetate gave the corresponding 2-alkylthio-5-(pyrazolin-3-ylmethylidene)-3,5-dihydro-4H-imidazol-4-ones in the yields from 30 to 77%. The oxidation of (5Z)-3-phenyl-5-[(1,5-diphenylpyrazolin-3-yl)methylidene]-2-methylsulfanyl-4,5-dihydroimidazol-4-one with lead tetraacetate led to the corresponding pyrazole in 48% yield.

Regioselective Synthesis of 3- and 5-Functional Derivatives of Pyrazolidine. 1. Synthesis of Ketones of the Pyrazolidine Series

When 5-hydroxypyrazolidines reacted with ketones on the surface of basic adsorbents the 3-regioisomers were obtained in addition to the expected 5-oxoalkylpyrazolidines. The conditions for the regiodirection of the process have been found.

Reactions of Hydroxyazolidines with π-Donor Heterocycles. 3. Reaction of 1-Acetyl-5-hydroxypyrazolidines with Oxindoles

The reaction of oxindoles with 5-hydroxypyrazolidines on the surface of potassium fluoride-modified alumina leads to 3-(5-pyrazolidinyl)oxindoles. The structure of these products was studied.

Acylation of 1-arylpyrazolidin-3-ones

Acylation of 1-arylpyrazolidin-3-ones using aromatic acid anhydrides and chlorides in the presence of base occurs principally at the oxygen atom to give 1-aryl-3-acyloxy-2-pyrazolines, subsequent heating or microwave irradiation of which leads to the corresponding N-acylpyrazolidin-3-ones. The action of aliphatic acid anhydrides and chlorides on 1-arylpyrazolidin-3-ones gives predominantly the N-acylpyrazolidin-3-ones.