Synthesis and Characterization of Tungsten Doped Vanadium Dioxide Nanopowders by Thermolysis

The thermochromic (TC) materials, characterized by the optical property being able to change reversible upon temperature, have attracted great interest and been extensively studied. Vanadium dioxide (VO2) is one of the most feasible TC materials. VO2 was …     

Synthesis of aza-crown compounds by intramolecular cyclization of ω-amino acids

A method for the synthesis of aza-crown compounds by the intramolecular cyclization of -amino acids with subsequent reduction of the lactam to a macrocyclic amine was developed. 1,8-Diazacyclotetradecane and 1,8-dioxa-4,11-diazacyclotetradecane were synthesized in preparative yields. The structural assignments were made using the IR, ¹H and ¹³C NMR, and mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 247–255, February, 1992.     

Ring Cleavage of N-Alkylisoxazolium Salts by Lithium Dialkylcuprates: Synthesis of β-Enaminoketones

N-Alkylisoxazolium salts undergo ring cleavage when treated with lithium dialkylcuprates to give β-enaminoketones in high yields.     

Ring Cleavage of N-Alkylisothiazolilm Salts by Complex Metal Hydrides. Synthesis of β-Enaminothioketones

N-Alkylisothiazolium salts undergo ring cleavage when treated with complex metal hydrides to give β-enami-nothioketones in high yields.

The isothiazole nucleus is remarkably stable to chemical attack by reducing agents.¹ In fact, little work has been published on reactions involving reductive cleavage of the isothiazole ring. Thus, other azole systems as isoxazole are readily cleaved by catalytic hydrogenolysis whereas the isothiazole nucleus, in the same conditions, remains unchanged.² However there are instances in which ring cleavage occurs. For example, cleavage of isothiazole during lithiation at the 5-position gives a small proportion of a β-mercaptoenone resulting from the cleavage of the N-S bond.^3,4 Isothiazoles are reductively desulfu-rized by Raney nickel and this method has been used by Woodward in a remarkable synthesis of colchicine.⁵     

Ring Cleavage of Cyclic 2-Nitroketones by KF Catalyst: A General Synthesis of ω-Nitroacids and ω-Nitroesters

Preparation of ω-nitroacids and ω-nitroesters has been achieved by ring cleavage of 2-nitrocycloalkanones, under basic condition (KF), in water (THF solution) or alcohol.     

A Convenient Synthesis of ω-Acetylenic Acids

ω-Acetylenic acids are valuable intermediates in the synthesis of long-chain acids. Their dimagnesium salts may be alkylated with 1-bromo-2-alkynes or 2-alkenes to synthesize many important naturally occurring fatty acids^1–3. Also, internally-monounsaturated acids are prepared by alkylation of ω-acetylenic acid dilithium salts^4,5 or the sodium salts of their N,N-dimethylamides⁶.     

Synthesis of ω-(2-oxocyclododecyl)alkanoic acids by alkylation of cyclododecanone with ω-haloalkanoic esters under conditions of phase-transfer catalysis

(-(2-Oxocyclododecyl)alkanoic acids have been obtained by alkylation of cyclododecanone with alkyl 3-bromopropionate, 5-iodopentanoate, and 11 -bromoundecanoate under conditions of phase-transfer catalysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2521–2523, December, 1995.     

Synthesis of Symmetrical Polyamide–Sulfonimides Based on Bis-saccharin Dicarboxylic Acid Dichlorides

Russian Journal of General Chemistry - Polycondensation of ethylene-bridged bis(saccharincarbonyl chlorides) with aliphatic diamines afforded soluble polyamide–sulfonimides. The effects of...     

Stereoselective Synthesis and Bioactivities of New ω-Azolyalkenes

ManyN-vinyltriazolesareeffectivefungicides"',theyhavebeenf()undtoinhibitbiosynthesisofergosterolinfungalcells,suchasdiniconazo1e(S-33O8)anduniconazole(S-33O7).Owingtothemechanismofthebioactivitiesrelatescloselytoconfigurationofthisfungicidals,newsyntheticmethodsareneedednotonlythenovelcarbonskeletonbutalsogoodconditionsfOrgettingageometricalisomerwhichshowsbetterfungicidalactivity.Fromthispointofview,alsoourpreviousworkaboutylidechemistry',wedesignedaroutetothestereoseletivesysthesisofthetit…     

One-Pot Synthesis of α-Monosubstituted Pyridiniums from Corresponding Pyrylium Salts

Abstract

α-monosubstituted pyridiniums were readily prepared by the one-pot reaction of their corresponding pyrylium salts and primary amines. This result shows that such kind of pyridiniums can be prepared via this route. It was proved that the number of phenyl groups at the pyrylium ring had a crucial effect on this one-pot synthetic route.     

Synthesis of S-Alkylisothiuronium Halides by Reaction of Thiourea with ω-(4-Hydroxyaryl)alkyl Halides

A number of new S-alkylisothiuronium salts were synthesized by reaction of -[4-hydroxy(methoxy)aryl]alkyl halides with thiourea. The resulting isothiuronium salts in aqueous solution react with sodium (potassium) halides to form halogen exchange products.     

A Facile Synthsis of ω-Bromo-Diene Via Solid/LiquidTransferred Wittig Reactions of ω-Bromobutyltriphenylphosphonium Salts With α.β -Unsaturated Aldehydes

ThesimplifiedWittgreactionunderthesolid/liquidconditionshasbeenappliedinorganicsynthesisasausefulmethod'.Theimplementationofthisreactioncangivehighyieldsinsomecaseswhereasinananhydroushomogeneousmediumleadstoapooryield'.TherearefewreportsonthedirectWittigreactionofcobromoaIbyfiriphenylphosphonturnsaftSwithaldehydes3.AnearlystudyonthereactionusingRONaasabaseresultedacomplexmixtureofalkenes',becauseofthepartialeliminationofHBrorthecycliZationreaction.Themethodofadirectpreparationofin-unsatur…     

Direct Synthesis of α-Acyl Methylenetriphenylarsoranes from Readily Available Arsonium Salts

α-Acyl arsoranes can be synthesized by the acylation of readily available salts in the presence of triethylamine in moderate to good yields.     

Synthesis of conjugated ω-dimethylaminocarbonyl compounds containing an azomethine fragment

Methods have been studied for synthesis of conjugated -dimethylaminocarbonyl compounds containing an azomethine fragment. The structures were established of all products from reaction of 2-aza-3-dimethylaminoacrolein acetal with CH-acids and of DMF acetal and -dimethylaminoacrolein animal with primary amines. It was shown that in many cases these reactions are accompanied by cleavage of the C=N. C-N and C=C bonds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2348–2356, October, 1991.     

Synthesis and Intramolecular Cyclization of ω-Haloalkyl Dithiophosporus Acid Esters

y -Haloalkyl dithiophosphorus acid esters undergo the thermal rearrangement resulting in the corresponding 2-oxo-1,3,2-dithiaphosphacyclanes.     

A Practical Synthesis of ω-Aminoalkanoic Acid Derivatives from Cycloalkanones

A practical synthetic route to N-Boc protected or Boc-amino acid coupled ω-aminoalkanoic acids is reported and exemplified by the preparation of 8-(t-butoxycarbonylamino)caprylic acid 2 and (N-t-butoxycarbonylphenylalanyl)-8-aminocaprylic acid 3. The sequence does not involve column chromatography, hydrogenation, azide or bromine related rearrangements, and therefore is amenable to scale-up. Homologues of the ω-aminoalkanoic acid derivatives may also be prepared by using different cycloalkanones.     

Synthesis and biological evaluation of anthranilamide-based non-peptide mimetics of ω-conotoxin GVIA

Non-peptide mimetics based on an anthranilamide ‘scaffold’ possessing fragments that mimic Lys2, Tyr13 and Arg17 in ω-conotoxin GVIA have been prepared. Compounds were assayed for binding to the voltage-gated calcium channels Ca_v2.2 (‘N-type’) and Ca_v2.1 (‘P/Q-type’) in rat brain. The primary synthetic target, 2-(6-amino-hexanoylamino)-5-(3-guanidino-propoxy)-N-[4-(4-hydroxyphenoxy)-phenyl]-benzamide (2a), exhibited low μM binding to Ca_v2.2 and was more than 30-fold selective for Ca_v2.2 over Ca_v2.1.