Showing papers by "Yu. A. Strelenko published in 1996"

A novel general method for the synthesis of nitrones by reaction of nitroso compounds with anions of aliphatic nitro compounds

Abstract: Anions of aliphatic nitro compounds R1R2C=NO2− react with nitroso compounds RNO to give nitrones R1R2C=N(O)R. Salts of nitro compounds with metals and Et3N, as well as trimethylsilyl nitronates in the presence of F−, can serve as the sources of the anions. The structure of the nitrones was established by NMR spectroscopy. 1,3-Dipolar cycloaddition of a series of the nitrones obtained to olefins was investigated.

New reactions of aci-1-nitropropane trimethylsilyl ester with 4-nitronitrosobenzene in the presence of trimethylsilylating reagents

Abstract: We found new unusual reactions of trimethylsilyl ester of aci-l-nitropropane (1) with 4-nitronitrosobenzene (2) in the presence of silylating reagents (Scheme 1). The reaction of compound 1 (1.2 equiv.) with compound 2 (1 equiv.) in the presence of MeC(OSiMe3)=NSiMe 3 (BSA) (2.5 equiv.) affords N(4-nitrophenyl)-N-(1 -acetylaminopropyl)N-trimethylsilyloxyamine (3), which is converted into N-(4nitrophenyl)-N-(1-acetylaminopropyl)hydroxylamine (4) on treatment with a catalytic amount of KF in MeOH. At the same time, the reaction of compound 1 (1.3 equiv.) with compound 2 (1 equiv.) in the presence of Me3SiCI/Et3N (2.5 equiv.) yields 1-(4-nitrophenylimino)-2-(trimethylsilyloxyimino)propane 1-N-oxide (5) (see Scheme 1). One may assume that l-(4-nitrophenylimino)propane N-oxide (A) is the key intermediate of both reactions. At present, the mechanism of these transformations and the possibility of conducting them using other substances are being studied.

Acylation of aliphatic diamines with methyl nitroacetate

Abstract: N,N′-Bis(nitroacetyl)diamines were synthesized for the first time by the reaction of methyl nitroacetate with aliphatic diamines in H2O or EtOH in the presence of pyridine or imidazole. In the case of 1,2-ethylenediamine, theN-mononitroacetyl derivative was isolated as an intermediate product.

Stereoselective Free Radical Cycloaddition‐Macrocyclization in Facile Synthesis of trans‐Cyclohexano‐fused 12‐Membered Crown Thioethers.

Abstract: Homolytic cycloaddition of dithiols 1,2 derived from trans- and eis-1,2-cyclohexanediols to alkynes, induced by Pr3B-O2, offers an extremely simple approach to trans- and cis-cyclohexano-fused 12-membered crown thialactones 4a-c-7a-c. The reaction of trans-1 proceeds with pronounced remote 1,6-asymmetric induction to give predominantly (IS *, 6R *, 12S *)-4a–c, while cis-2 reacts nonstereoselectively. Basing on molecular mechanics calculations the stereoselectivity is rationalized as a result of entropy favored pathway of macrocyclization.

New Products from the Reactions of 4,5‐Dihydroxyimidazolidin‐2‐ones with Sulfonamides.

Abstract: For the first time the interactions of N -alkyl- and N , N ′-dialkyl-4,5-dihydroxyimidazolidin-2-ones with sulfonamides have been studied and as a result N -alkyl- and N , N ′-dialkyl-4(5)-aryl(alkyl)sulfonyliminoimidazolidin-2-ones and 4,4′-sulfonyldiiminobis( N , N ′-dimethylimidazolidin-2-one) have been synthesized.