Reaction of hydrazonoyl halides with N-aryl substituted benzamidines

The reaction between hydrazonoyl halides and N-arylbenzamidines leads to the simultaneous formation of products derived from a substitution and a cycloaddition reaction via two independent paths.     

The contraction of K to NM

By studying the contraction of K to $\text{N}\text{M}$ inside the Iwasawa decomposition of a semisimple Lie group of real rank 1, we realize the representations of $\text{NM}$ as limits of representations of K, obtaining in particular, limiting formulas for matrix entries.     

An electrochemical investigation on the reduction path of the arene complexes [CpM(arene)]2+ and [(η-9-SMe2-7,8-C2B9H10)M(arene)]2+ (M=Rh, Ir)

The reduction behavior of the isoelectronic complexes [CpM^III(η⁶-C₆R₆)]²⁺ (M=Rh, Ir; R=H, Me) and [(η-9-SMe₂-7,8-C₂B₉H₁₀)M^III(η⁶-C₆R₆)]²⁺ (M=Rh, Ir; C₆R₆ = C₆H₆, C₆H₅OMe, C₆H₃Me₃) has been studied by cyclic voltammetry and controlled potential coulometry in acetonitrile and propylene carbonate at 253 and 298 K, respectively. The extent of chemical reversibility of the pertinent sequences Rh(III)/Rh(II)/Rh(I) and Ir(III)/Ir(I) is highly dependent on both the nature of the solvent and the intrinsic electronic properties of the arene substituents. The arene η⁶ coordination makes the derivatives in their lower oxidation states notably short lived, even if, in some cases, the use of propylene carbonate improves their stability or causes the increase in their lifetimes before changing the arene coordination from η⁶ to η⁴. Cations [(η-9-SMe₂-7,8-C₂B₉H₁₀)M(η⁶-C₆R₆)]²⁺ were obtained by the bromide abstraction from [(η-9-SMe₂-7,8-C₂B₉H₁₀)MBr₂]₂ with Ag⁺ in the presence of benzene and its derivatives. The structure of [(η-9-SMe₂-7,8-C₂B₉H₁₀)Ir(η⁶-C₆H₅OMe)](BF₄)₂ was determined by X-ray diffraction.     

Identification of the nitrosation reaction products of alkyl esters of 1,2-benzisoxazole-3-acetic acid by chemical and crystallographic methods

The reaction between methyl or ethyl esters of 1, 2-benzisoxazole-3-acetic acid and iso-amyl nitrite is reported. The main product is identified as 4-(2′-hydroxyphenyl)furazan-3-carboxylic acid ( 4 ) by chemical and X-ray crystal structure analyses. The synthesis of esters of E- and Z-α-(hydroxyimino)-1, 2-benzisoxazole-3-acetic acid is also reported.     

ON THE FORMATION AND REACTIVITY OF DIOXIRANE INTERMEDIATES IN THE REACTION OF PEROXOANIONS WITH ORGANIC SUBSTRATES*

Abstract— Kinetics and ¹⁸O-labeling studies have provided evidence for the involvement of dioxirane intermediates (V) in the ketone-catalysed decomposition of peroxomonosulfate (Caroate) HSO;. Reaction rates depend on ketone structure. In competition with catalysis of peroxide decomposition, the dioxirane intermediate is capable of oxidizing several organic and inorganic substrates. Thus, cis- and rrans-cinnammic acids could be converted stereospecifically into the corresponding epoxides. Also, oxidation of phenylpropiolic acid, a substrate which is representative of weakly nucleophilic alkynes, could be carried out using the Caroatehetone oxidizing system. Under the conditions adopted, no oxidation of the substrates examined was found to occur in the absence of ketone. The possibility that formation of dioxathiirane intermediates (XXII) occurs following a side pathway in the reaction of Caroate with sulfoxides (which produces sulfones in high yield) has been explored. Preliminary experiments using ¹⁸O-labeling of p-tolyl phenylsulfoxide, however. failed to support this hypothesis. pointing out the need for further detailed studies.