A. Yu. Gavrilova

Reactions of cyclopropanes with potassium dihaloiodates

Reactions of potassium dihaloiodates with arylcyclopropanes and polycyclic compounds containing a cyclopropane fragment characterized by different degrees of strain lead to formation of mixed 1,3-halogenation products. If iodohalogenation should give rise to products having a iodine atom in the benzylic position, 1,3-dichloro or 1,3-dibromo derivatives are formed. Iodohalogenation of exo-tricyclo[3.2.1.02,4]octane is stereoselective and is accompanied by Wagner-Meerwein rearrangement.

Transformations of gem-dichloroarylcyclopropanes in the reaction with NOCl·2SO3. Synthesis of 3-aryl-5-chloroisoxazoles

Nitrosation with complex NOCl·2SO3 of gem-dichloroarylcyclopropanes containing acceptor substituents in the aromatic ring proceeded chemo- and regioselectively affording 3-aryl-5-chloroisoxazoles in high yields. The presence of donor substituents complicated the reaction by the occurrence of competing processes.

4,5-dihydroisoxazoles from arylcyclopropanes: II. Reaction of arylcyclopropanes with nitrosyl chloride activated by sulfur(VI) oxide

Arylcyclopropanes react with nitrosyl chloride activated by sulfur(VI) oxide to give the corresponding 5-aryl-4,5-dihydro-1,2-oxazoles in quantitative yields. The complex NOC1·2SO3 is a highly efficient nitrosating agent which makes it possible to involve in the process arylcyclopropanes having both donor and acceptor substituents in the aromatic ring.

Δ2-isoxazolines from arylcyclopropanes: III. Phenylcyclopropanes substituted in three-membered ring in reaction with nitrosyl chloride activated with oxides of sulfur(IV, VI)

The reaction of phenylcyclopropanes substituted in the three-membered ring with nitrosyl chloride activated with sulfur(IV, VI) oxides provided in good yield substituted 5-phenylisoxazolines as a mixture of structural isomers.

2-isoxazolines from arylcyclopropanes: I. Monoarylcyclopropanes in a reaction with nitrosyl chloride activated by sulfur(IV) oxide

A reaction of monoarylcyclopropanes with nitrosyl chloride activated by sulfur (IV) oxide gave in good yields 5-arylisoxazolines. The reaction is of electrophilic character. A scheme of the reaction was suggested.

Transformations of gem-dibromoarylcyclopropanes under nitrosation conditions on treatment with NOCl·(SO3)n

The reaction of 2-aryl-1,1-dibromocyclopropanes with adduct NOCl·(SO3)n leading to 3-aryl-5-bromoisoxazoles as a result of nitrosation—heterocyclization of the cyclopropane ring was studied. The reaction is accompanied with electrophilic aromatic bromination. The mechanism of the transformation was discussed, the optimal reaction conditions to enhance the reaction selectivity were developed.

Reaction of unsaturated compounds with the thiobisamine-SOHal2 system

A convenient method for the synthesis of di(β-haloalkyl)sulfides based on the reaction of unsaturated compounds with the thiobisamine-SOHal2 (Hal = Cl, Br) system was created. The reaction proceeds through an electrophilic mechanism with the formation of trans-addition products. Reactions with alkynes result in the formation of a mixture of regioisomeric divinyl sulfides.

Two-step synthesis of β-haloalkanesulfonamides from alkenes

Aromatic sulfonamides have long been successfully used in medicine as antibacterial, diuretic, and hypoglycemic drugs [1]. It has been found recently that aliphatic sulfonamides also exhibit antimicrobial activity [2]. The present work was aimed at developing a procedure for the synthesis of β-haloalkanesulfonamides which are promising as intermediate products for the preparation of β-substituted alkanesulfonamides due to the possibility for replacement of the halogen atom by other functional groups.

Aminosulfenates in the electrophilic addition reactions

The reactions of methyl and ethyl diethylaminosulfenates and ethyl piperidinylsulfenate with cyclohexene and norbornene in the presence of chloro- or bromotrimethysilanes were studied.

Oxonitrates VO(NO3)3 and MoO2(NO3)2 and nitronium and nitrosonium nitratometallates as nitrating agents

Dissolution of vanadium in anhydrous HNO3 followed by exposure of the solution in a dessicator over P2O5 gave liquid vanadyl trinitrate (I). The X-ray diffraction analysis of I was carried out for a single crystal grown on cooling the liquid in a sealed capillary. The structure is composed of VO(NO)3 molecules in which the V atom has an unusually high C.N. 7; it coordinates the terminal O atom and three bidentate nitrate groups to form a distorted pentagonal bipyramid as the coordination polyhedron with the terminal O atom occupying one axial vertex. Using the GAMESS program package, ab initio calculation of the structure of VO (NO3)3 in the liquid phase was carried out. It was shown that in all three physical states, vanadyl trinitrate retains its molecular structure almost invariable. Toluene and naphthalene nitration using I and (NO2)[Fe(NO3)4], NO[Cu(NO3)3], (NO)3/4(NO2)1/4[Zr(NO3)5], and MoO2(NO3)2 proceeds at high rates at low temperatures to give an unusually high para-nitrotoluene percentage in the products as compared with the ortho-isomer. The activity of the studied compounds in the nitration of naphthalene decreases in the series VO(NO3)3 > (NO)3/4(NO2)1/4[Zr(NO3)5] > MoO2(NO3)2.