A. B. Zolotoi

Stereoselective synthesis of tricyclic derivatives of 2-amino-1-pyrrolin-5-one dimethyl acetals

Reactions of a tetracyanobicycloalkene (1) with methanol and ethylene glycol give derivatives of 2-aminopyrrolin-5-one (2 and 3), and acid hydrolysis of3 gives an imide (4). According to an X-ray structural investigation, acis orientation of the heterocycle (with respect to the C=C bond) is realized in2; in the case of4, thecis/trans ratio of the isomers in the crystal and solution is 2∶1.

Chemistry of 1,1,2,2-tetracyanoethane. 11. Synthesis and stereochemical characteristics of 3-methyl-5-oxo-2′-amino-5′-phenyl -3′,4′,4′-tricyanoisoxazoline-4-spiro-1′-cyclopent-2′-ene

The Michael condensation of 1,1,2,2-tetracyanoethane with 3-methyl-4-benzylideneisoxazolin-5-one having the Z configuration leads to a heterocyclic spiran with retention of the cis orientation of the phenyl and keto groups. The deviations of the series of bond angles of the spiran from the standard values, the abnormal lengths of the C-C bonds adjacent to the gem-dicyano group, and the appearance of nonbonding >C=O(...)C≡N interactions and conjugation effects in the enaminonitrile fragment are discussed.

Formation pathways and structure—Property interrelationship of 3-imino-1-methyl-5,5-dialkyl-4,7,7-tricyano-2-oxabicyclo-[2.2.1]heptane derivatives

The problems of the structure—property interrelationship of 3-imino-2-oxabicyclo[2.2.1]heptane derivatives are discussed on the basis of x-ray diffraction studies (XDS). A pathway for the formation of the bicyclic compounds is proposed, and the realization of spirans in the reaction of sym-tetracyanoethane with conjugated cyclic systems containing s-cis C=C and C=O fragments is substantiated. The factors responsible for the syn orientation of the oxygen atom and the N-substituent of the imino group are analyzed. It is shown that a change in the steric hindrance in the bicyclic compounds leads to a change in the conformation of the latter. The reasons for the shortening of the Csp3-Csp3, Csp3-Csp and C=N exo bonds and the correlation of the XDS and IR spectroscopic data are examined. From the XDS data for N-bromo-substituted imines, a model for Br+...N≡C electrophilic attack was proposed

Chemistry of 1,1,2,2-tetracyanoethane. 14. Structure of 3-(N′,N′-dimethyl-N-acetylhydrazino)-5-methyl-1,1,2,2-tetracyanocyclopentane in solution and the crystal and the reasons for the selective addition of nucleophiles to a specific cyano group

Knowledge of the stereochemistry of starting I and products II and III indicated a stepwise pathway for this reaction such that the nucleophilic agents attack the trans C~N group in the G-position to the methyl substituent in I [2]. In the present work, NM!E spectral and x-ray diffraction data were used to analyze the structure of I in solution and in the crystal and the reasons for the selective addition of the nucleophile to a specific cyano group.

Chemistry of 1,1,2,2-tetracyanoethane. Reaction of 1,1,2,2-tetracyanoethane with α-dicarbonyl compounds

Abstract1,1,2,2-Tetracyanoethane reacts with α-dicarbonyl compounds in water to form 7-amino-4-hydroxy-1,8-dicyano-3-aza-6-oxabicyclo-[3.3.0]oct-7-en-2-ones. Their structures were confirmed by IR,13C NMR and mass spectra.

Chemistry of 1,1,2,2-tetracyanoethane. 12. Condensation of 1,1,2,2-tetracyanoethane with crotonaldehyde in alcoholic solution

Conclusions1.Condensation of 1,1,2,2-tetracyanoethane with crotonaldehyde and the solvent (alcoholic medium) takes place in the ratio 1∶2∶1 to give 2-amino-5-methyl-3-(1-methyl-3-alkoxyallyl)-1-formyl-3, 4,4-tricyanoyclopentenes.2.On the basis of an x-ray diffraction analysis of the product with an isopropoxy-group in the 3-position, the main features of its molecular structure are discussed, and a stepwise route is proposed for the reaction and its stereochemical features examined.

Chemistry of 1,1,2,2‐Tetracyanoethane. Part 7. Synthesis and Addition Reactions of Nucleophilic Agents to One of the Cyano Groups of 3‐(N′,N′‐Dimethyl‐N‐acetylhydrazino)‐5‐methyl‐1,1,2,2‐tetrahydrocyanocyclopentane.

Starting with the tetracyanoethane (I) and the crotonaldehyde hydrazone (II), the title compound (V) is synthesized as shown in the reaction scheme.

Chemistry of 1,1,2,2-tetracyanoethane. Part 7. Synthesis and nucleophilic additions to one cyano group in 3-(N′,N′-dimethyl-n-acetylhydrazino)-5-methyl-1,1,2,2,-tetracyanocyclopentane

Conclusions1.Reactions of 1,1,2,2-tetracyanoethane were performed to give 3-(N′,N′-dimethyl-N-acetylhydrazino)-5-methyl-1,1,2,2-tetracyanocyclopentane. The latter reacted with nucleophiles to give 3-azabicyclo[3.3.0]oct-2-enes and 3-azabicyclo[3.3.0]oct-2-en-4-ones.2.X-ray analysis has been used to establish the stereochemistry of the cyclopentanes and bicyclic compounds derived from them.

Synthesis of derivatives of 4-imino-2-amino-2-imidazoline. New example of a multicomponent condensation involving isonitriles

Isonitriles have been found to react with ketones and ammonium and methylammonium thiocyanates in methanol or ethyleneglycol at 20 °C to form derivatives of 4-imino-2-amino-2-imidazoline and 2,4-diaminoimidazolium salts.