Epoxidation of Stereoisomeric Benzoylureas of Norbornene Series

Russian Journal of Organic Chemistry -     

Epoxidation of Multiblock Copolymers of Norbornene and Cyclooctene

The epoxidation of double bonds in random multiblock copolymers of norbornene and cyclooctene is studied for the first time. The initial copolymers with different composition and average block length are synthesized via the cross-metathesis reaction between polynorbornene and polycyclooctene in the presence of the first-generation Grubbs catalyst. New multiblock copolymers containing oxirane fragments in the backbone are obtained with a yield of 85–92% through epoxidation conducted under the action of m-chloroperbenzoic acid in toluene. The kinetics of epoxidation of polynorbornene, polycyclooctene, and their multiblock copolymers in deuterochloroform and deuterobenzene is investigated via the in situ monitoring of transformation of double bonds using ¹Н NMR spectroscopy. It is shown that on the whole the modification of cyclooctene units occurs more easily in copolymers than that in the homopolymer. The thermal properties of epoxidized homo- and copolymers are examined. It is found that upon epoxidation the glass-transition temperature and the melting temperature of multiblock copolymers increase by 40–50 and 20–30°С, respectively, wherein the degree of crystallinity and the temperature of melting grow with the length of the cyclooctene block.     

Heterocyclization of acylthiosemicarbazides

The review summarizes published data on the behavior and reactions of acylthiosemicarbazides and their derivatives, which lead to the formation of heterocyclic systems, including methods of preparation in addition to synthesis of pyrrole, thiazole, thiadiazole, thiadiazolidine, and triazole derivatives as well as fused heterocyclic compounds. J. Heterocyclic Chem., (2012).     

Heterocyclization of N-propionylaminoindoline

Treatment of N-propionylaminoindine with a solution of phosgene in benzene gives the 1-[(indolin-1-yl)imino]propyl ester of 7-(1-cyanoethyl)indoline-1-carboxylic acid. The structure of the compound was proved using¹H and¹³C NMR spectroscopy.All-Russian Science Center for the Safety of Biologically Active Materials, Staraya Kupavna, Moscow Region 142450. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 168–170, February, 1995. Original article submitted January 11, 1995.     

Heterocyclization of 1,3-Butadienethiolates

Condensation of derivatives of ethoxymethylenecyanoacetic acid with cyanothioacetamide with base catalysis gave butadienethiolates and mercaptopyridines. On interaction with alkyl halides, butadienethiolates are cyclized into alkylthiopyridines, but their reactions with phenacyl bromides give substituted thiazoles.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 589–596, April, 2005.     

Microwave-Assisted Efficient Methylation of Alkyl and Arenesulfonamides with Trimethylsulfoxonium Iodide and KOH

Abstract

A solvent-free synthesis of N-methyl and N,N-dimethylsulfonamides has been achieved by treating the primary and secondary sulfonamides with Me₃S⁺OI^? and KOH under microwave irradiation on alumina support.     

Synthesis and Heterocyclization of 3-Arylaminothiocrotonanilides

Reactions of acetylthioacetanilide with arylamines in acetic acid in the presence of sodium acetate give 3-arylaminothiocrotonanilides in good yields. When treated with -bromoacetophenone in acetone, these products are converted to substituted 4-hydroxy-²-thiazolinium bromides, one of which was dehydrated to obtain the corresponding thiazolium bromide. The structure of the heterocyclization products was confirmed by single crystal X-ray diffraction and NMR study of 2-acetonylidene-3,4-diphenyl-2,3-dihydrothiazole formed by dehydration of the corresponding ²-thiazolinium salt with simultaneous hydrolysis.     

The Vinyl Homopolymerization of Norbornene

A full literature and patent account (about 100 references) is given on work describing vinyl polymerization to form the homopolymer poly(norbornene). The interest in vinyl‐poly(norbornene) is driven by its dielectric and mechanical properties for the technical application as an interlevel dielectric in microelectronics applications. For comparison, the norbornene/olefin copolymerization is discussed also. The metal catalysts are introduced and important polymer product properties are emphasized. The six possible isomers for stereoregular poly(norbornene) are presented.     

Photoaddition of Iodoform with Norbornene

The reaction of norbornene with iodoform in the inert solvent under irradiation resulted in Kharasch type addition to give endo-3-iodo-exo-2-diiodomethyl-bicyclo[2.2.1]heptane, and a carbene addition to give tricyclic compound, anti-3-iodo-exo-tricyclo[3.2.1.0^2,4]octane. The structural assignments of these adducts are based on elemental analyses, ir, nmr, and mass spectral studies.     

Norbornene probes for the study of cysteine oxidation

Cysteine residues on proteins can react with cellular oxidants such as hydrogen peroxide. While this process is important for scavenging excess reactive oxygen species, the products of this oxidation may also mediate cell signalling. To understand the role of cysteine oxidation in biology, selective probes are required to detect and quantify its occurrence. Cysteine oxidation products such as sulfenic acids are sometimes unstable and therefore short-lived. If such cysteine derivatives are to be analysed, rapid reaction with the probe is required. Here we introduce norbornene derivatives as probes for cysteine oxidation, and demonstrate their ability to trap sulfenic acids. The synthesis of norbornene derivatives containing alkyne or biotin affinity tags are also reported to facilitate the use of these probes in chemical biology and proteomics.     

Radical Heterocyclization and Heterocyclization Cascades Triggered by Electron Transfer to Amide‐Type Carbonyl Compounds

Radical heterocyclizations triggered by electron transfer to amide‐type carbonyls, using SmI₂‐H₂O, provide straightforward access to bicyclic heterocyclic scaffolds containing bridgehead nitrogen centers. Furthermore, the first radical heterocyclization cascade triggered by reduction of amide‐type carbonyls delivers novel, complex tetracyclic architectures containing five contiguous stereocenters with excellent diastereocontrol.     

Heterocyclization of Amidophenacylation Products of Uracil

When uracil is reacted with benzoylamino(chloro)acetophenone, we obtain two amidophenacylation products depending on the condensation conditions. The first product contains an amidophenacyl moiety at the N¹ center, and in the second product two such moieties are located at the N¹ and N³ centers of the uracil. Treatment of these accessible uracil derivatives with phosphorus oxychloride, thionyl chloride, or phosphorus pentasulfide leads to cyclization of the amidophenacyl side group, which is used to synthesize a number of modified pyrimidine bases with 2,5-diphenyloxazole or 2,5-diphenylthiazole residues.     

2-Aminothiophene. Heterocyclization of benzylthionitriles

Synthesis of unstable 2-aminothiophene by way of its hydrochloride salt has been achieved in excellent yield. The key reaction in the scheme involves a novel heterocyclization of benzylthionitriles, which would appear to have general utility. Spectral and physical properties are tabulated and a possible mechanism is proposed.     

Epoxidation of homoisoflavones

A comparative study of the epoxidation of homoisoflavones (3‐benzyl‐4‐chromones) 1–4 has been performed by various oxidizing agents, víz. Epoxidation with isolated dimethyldioxirane (Method A), with alkaline hydrogen peroxide (Method B), and with sodium hypochlorite (Method C) to obtain the epoxides 4–8 . Compounds 2 and 3 have also been oxidized with a combination of dimethyldioxirane and Jacobsen's Mn(III)salen catalysts (R,R)‐11 and (S,S)‐ 11 to afford 3‐benzoyl‐4‐chromones 9 and 10 . Structures of all new compounds have been elucidated by microanalyses, ir and nmr spectroscopic measurements.