The mass spectrometry of some t-butyl peresters

Mass spectrometry is suggested as a method for the general characterization of mono- and di-t-butyl peresters. In many instances it is possible to measure the molecular ion, especially in the mono-t-butyl peresters. The fragmentation patterns of various t-butyl peresters are presented.     

Photoinitiated polymerization of vinyl monomers by benzophenone t-butyl peresters

Benzophenone peresters undergo efficient photodecomposition when irradiated at 366 nm. This article reports peresters derived from benzophenone p,p′-dicarboxylic acid 1 which may produce radicals at two different centers in the same molecule. These peresters represent a unique new example of an efficient photoinitiator for acrylate and styrene polymerization.      

Cetylpyridinium bromide-catalyzed reaction of ortho-aminomethylphenols with para-nitrophenyldiphenyl phosphate

Cetylpyridinium bromide micelles accelerate the reaction of paranitrophenyldiphenyl phosphate with orthoaminomethylphenol by more than an order of magnitude in aqueous micellar solutions. The rate constants for this reaction are, however, about 50 times lower in the micellar phase than in water, i.e., the principal factor responsible for micellar catalysis in this reaction is concentration of the reagent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1126–1129, May, 1990.     

Indium(III) bromide-catalyzed hydroarylation of alkynes with indoles

Indium(III) bromide-catalyzed hydroarylation of alkynes with indoles leading to the synthesis of 3-vinylindoles in good to excellent yields was achieved. The E/Z ratio of the products depends on the substituents on the indole. This protocol is efficient and atom-economic from the synthetic point of view.     

Reactions of thihalogenoacetic acids—IV The reaction of trichloro- and tribromoacetic acids with ketimines

The reaction of trichloro- and tribromoacetic acids with some ketimines has been investigated. It has been found that these acids react with the ketimines in an organic solvent with evolution of carbon dioxide and with the formation of -(trihalogenomethyl)amine derivatives. The compounds obtained, when heated in alcohol undergo transformations, in the presence of water, with the formation of the corresponding -halogenoacylamines and -unsaturated acylamines as final products.     

Reactions of aromatic acetylenic ethers with triethylgermane

Conclusions The addition of Et₃GeH to the phenoxy- and phenylthioacetylenes under the influence of (Ph₃P)₃RhCl is both nonstereo- and nonregiospecific. The analogous reaction with 3-aroxy-1-propynes is stereospecific but nonregioselective.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2618–2620, November, 1982.     

Reactions of α-chloronitrones with unsaturated ethers

The Ag⁺ induced reaction of α-chloronitrones with unsaturated ethers goes in two parallel competitive directions. On the one hand cycloadducts like 3 are formed and on the other hand oxonium ions like 4. Formation of analogous oxonium compounds occurs also when α-alkoxynitrones are treated with Et₃O⁺BF₄^? in 1,2-dichloroethane. Formation of oxonium compounds with the enol-ethers is practically irreversible and leads to enol-ether fragmentation. With the saturated ethers compounds like 25 were formed and were used as a potential source of N-alkyl-N-vinyl-nitrosonium ions.     

Reactions of acylarylnitrosamines—II

Decomposition of acylarylnitrosamines in benzene produces not only free radicals as is well recognized, but also intermediate ion pairs. The generality of this dual mechanism is experimentally demonstrated by use of nucleophilically activated fluorine as a ‘label’. The appearance of acylfluoride in the reaction products from fluorine substituted acylarylnitrosamines is interpreted.     

Reactions of fluoroalkanesulfonyl azides with cyclic vinyl ethers

The addition reactions of fluoroalkanesulfonyl azides to dihydropyran or dihydrofuran were studied. These reactions do not give the corresponding N-fluoroalkanesulfonyl azilidines but N-fluoroalkanesulfonyl-tetrahydropyranon-2-imines or N-fluoroalkanesulfonyl-tetrahydro-furano-2-imines. The reaction mechanism is discussed.     

Reactions of acetals with alkyl 2-bromovinyl ethers

Summary A study was made of the condensation of benzaldehyde and acetaldehyde acetals with alkyl 2-bromovinyl ethers, as a result of which bromo ethoxy acetals of general formula RCH(OC₂H₅)CHBrCH(OR)₂ (R=C₆H₅ and CH₃) were formed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 282–285, February, 1965     

Heuristic Chemistry—Elimination Reactions

Besides additions and substitutions, elimination reactions play a fundamental role in organic synthesis. However, conceptual reviews of known 1,x‐elimination patterns that go beyond the typical olefin‐forming 1,2‐eliminations are scarce. To develop a broader understanding of elimination reactions, we follow a heuristic approach and deduce recurrent reaction patterns from traditional and specific elimination reactions. Our work demonstrates that 1,x‐elimination reactions and their outcomes can be easily rationalized by defined mnemonic categories.     

Reactions of alkyl furfuryl ethers and sulfides with n-butyllithium

The direction of the reaction of alkyl furfuryl ethers and sulfides with n-butyllithium is in agreement with the results of basic H-D exchange in the same compounds: In the case of the ethers H-D exchange and metallation take place primarily in the free a position of the furan ring, whereas in the case of the sulfides these reactions take place primarily at the methylene group of the side chain located between the sulfur atom and the furan ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 744–746, June, 1984.     

Technetium complexes with thioether ligands—III. Synthesis and structural characterization of cationic nitridotechnetium(V) complexes with thiacrown ethers

The first representative of a new class of TcN complexes with thiacrown ethers have been prepared by ligand exchange reaction of NBu₄[TcNCl₄] with 1,4,8,11-tetrathiacyclotetradecane (14S4), 1,5,9,13-tetrathiacyclohexadecane (16S4), 1,5,9,13-tetrathiacyclohexadecane-3,11-diole (16S4-(OH)₂) and 1,4,7,10,13,16-hexathiacyclooctadecane (18S6). The crystal structure of [TcNCl(14S4)]TcNCl₄ 1) consists of couples of independent cations with the metal in the oxidation state + 5 and hexavalent TcNCl₄⁻ anions. In the complex cation the metal is six-coordinated in a rather distorted octahedral geometry, being directly bound to four sulphur atoms from the macrocyclic ligand in the equatorial plane and to the nitrido atom and to one chlorine atom in the axial positions. The strong trans influence of the nitrido ligand causes an extreme lengthening of the Tc---Cl bond distance to 2.718 Å. The octahedral molecular structure of [TcNCl(18S6)]TcNCl₄ (3) is comparable with that of 1, but only four sulphur atoms of the thiacrown ether form the equatorial plane, two sulphur atoms remain non-coordinated, and the nitrido and Cl⁻ ligands are in axial positions. The most interesting feature in the structure of [TcNCl(16S4-(OH)₂)]Cl (5) is the observation of an exceptionally long Tc---N distance of 1.95 Å.     

The reaction of vinyl ethers with acridine

The reaction of vinyl ethers with acridine gives new acridine derivatives in the presence of an organic ammonium salt and alcohol. An organic ammonium salt such as acridinium chloride affect this reaction. All of the addition products were obtained as dihydroacridinyl derivatives. Moreover, in the reaction of ketene silyl acetal with acridine, the addition products were also obtained as the dihydroacridine derivatives.     

Reactions of ketenes—IX Reactions between ketene acetals and diphenylketene

Monoalkylketene acetals and monoarylketene acetals react with diphenylketene to give acylketene acetals (VII). These compounds can further react with diphenylketene to give 2,4-pyronone 4-acetals (IX), which, by mild acid hydrolysis, yields 2,4-pyronones (X).

Reaction of methylketene diethylacetal with two equivalents of diphenylketene yields 3,3-di-phenyl-5-methyl-6-diphenylmethylentetrahydropyran-2,4-dione 4-diethylacetal (XIV) in addition to small quantities of the pyronone acetal IXb.