Electrophilic heterocyclization of unsaturated amino compounds in the synthesis of nitrogen-containing heterocycles (review)

The literature data on the electrophilic heterocyclization reactions of unsaturated amines, enamines, amidines, amides, and urethanes are correlated. The factors that affect the reactivities of unsaturated amino compounds in electrophilic intramolecular-cyclization reactions are discussed. The problems involved in the regioselectivity of the addition of electrophiles and the stereochemistry of the resulting products are examined, and kinetic data are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 435–449, April, 1985.     

Electrophilic heterocyclization of unsaturated carboxylic acids in the synthesis of lactones (review)

Data on the electrophilic-heterocyclization reactions of , - and , -unsaturated carboxylic acids are correlated. The use of this reaction for the synthesis of substituted mono-, bi-, tri-, and polycyclic - and -lactones is demonstrated. Data on the regioselectivity of the addition of electrophiles and the stereochemistry of the resulting cyclization products are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1299–1316, October, 1988.     

Electrophilic heterocyclization of unconjugated dienes (review)

The results of research with the participation of unconjugated dienes in intra-molecular electrophilic heterocyclization are presented. It is shown that this reaction can be used for the synthesis of heterocycles with one, two, or more heteroatoms. The stereochemistry of the resulting heterocycles and the mechanism of heterocyclization is examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 867–880, July, 1984.     

Reaction of sulfur halides with unsaturated compounds

Conclusions Oxidation of 2,9-dichloro-13-thiabicyclo[8.2.1]cis-5-tridecene with tert-amyl hydroperoxide leads to the respective exo-sulfoxide and also to a derivative of 13-thiabicyclo[7.3.1]cis-5-tridecene, which is a product from rearrangement with enlargement of the thiacyclopentane ring to a thiacyclohexane ring.See [1] for Communication 11.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 384–389, February, 1976.     

Simultaneous microdetermination of sulfur and phosphorus in organic compounds

A simple method for the simultaneous determination of sulfur and phosphorus in 3–8 mg organic sample is presented. Following oxidative combustion by the oxygen flask method, sulfate is precipitated by addition of a known amount of Ba(II) and the excess of the latter is measured polarographically. After filtration, the quinoline phosphomolybdate method is used to precipitate phosphate; the unreacted Mo(VI) is determined polarographically. The mean relative error for 13 determinations was 2.99% for S and 4.07% for P; the mean relative standard deviation was 1.43 and 4.19%, respectively.     

Study of the reaction of sulfur halides with unsaturated compounds

The oxidation of thiabicyclotridecenes with various oxidizing agents proceeds selectively and, depending on the amount and strength of the oxidizing agent, gives sulfoxides, epoxy sulfoxides, or epoxy sulfones. The sulfur atom is initially oxidized, after which the double bond either undergoes epoxidation or hydroxylation.See [9] for communication XIITranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 475–478, April, 1976.     

Dicyanomethylene compounds and heterocyclization of acylthiosemicarbazides

(1,3‐Dioxo‐2,3‐dihydro‐1H‐inden‐2‐ylidene)propanedinitrile ( 1 , in ethyl acetate solution), 3‐(dicyano‐methylene)‐2‐indolone ( 2 , in ethanol/piperidine solution) and 7,7′,8,8′‐tetracyanoquinodimethane ( 3 , in pyridine solution) act on substituted acylthiosemicarbazides 4a‐d , forming the derivatives of oxoindeno‐pyrrolylidenehydrazide ( 5a‐d and 7a‐d ), thiazoloindolylidenehydrazide ( 12a‐d ), pyrroloindolylidene‐hydrazide ( 13a‐d ) and spiro[pyrrolylidene‐4,1′(cyclohexa‐2′,5′‐dienylidene)]propanedinitrile ( 18a‐d ). Rationales for these conversiones involving the nucleophilic addition on dicyanomethylene carbon atom are presented.     

Simultaneous spectrophotometric microdetermination of sulfur and phosphorus in organic compounds

A method is described for the simultaneous spectrophotometric microdetermination of sulfur and phosphorus in organic compounds. The interference of phosphorus in the determination of sulfur is avoided using a suitably modified barium chloranilate method. The samples analyzed include some pesticides and mixtures of organosulfur and organophosphorus compounds. The error does not exceed ±0.5% unlike the one reported in the earlier method.     

Catalytic synthesis of sulfur and phosphorus compounds via atom-economic reactions

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Syntheses and reactivity of novel unsaturated cyclic compounds containing phosphorus atoms

Kinetic stabilization of compounds containing heavy main-group elements through the use of bulky substituents is of current interest. The widely used 2,4,6-tri-t-butylphenyl group (Mes*) is recognized as a powerful bulky protecting group and has enabled us to successfully prepare various types of phosphorus compounds with unusual structures. When a phosphaalkyne carrying Mes* was treated with tBuLi and then quenched with MeOH, a 1,3-diphosphacyclobutene was obtained, whereas, when MeI was used as a quencher, a 1,3-diphosphacyclobutane-2,4-diyl was formed almost quantitatively as a stable biradical compound. The reaction mechanism for the formation of both compounds can be explained by a phosphide intermediate, which can be formed via dimerization of the phosphaalkyne promoted by tBuLi. Some other diphosphacyclobutane-2,4-diyls with various substituents were prepared in a similar fashion and showed interesting reactivities including ring expansion, oxidation, isomerization and so on.     

Organo-nonmetallic chemistry: Pentacoordinate,ten-electron (10-X-5) compounds of silicon,phosphorus and sulfur

Abstract

We have shown that ligands to nonmetals can be designed to stabilize five-coordinate species, relative to four- or six-coordinate ones. Nondissociative permutational isomerization of identically substituted hypervalent 10-Si-5 siliconate anions and neutral 10-P-5 phosphoranes is faster for the isoelectronic isostructural silicon species. Nucleophile mediated stereochemical inversion in silanes which are substituted by ligands which stabilize trigonal bipyramidal species is shown to proceed by pseudorotation of an intermediate 10-Si-5 species.     

Iodometric microdetermination of phosphorus,sulfur and chlorine in organic compounds

Summary A method is presented for the determination of phosphorus, sulfur and chlorine in organic compounds in absence of nitrogen by iodometry. The titration is carried out in 50% acetone solution in order to eliminate the interference of hydrogen peroxide.

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Zusammenfassung Ein Verfahren zur jodometrischen Bestimmung von Phosphor, Schwefel und Chlor in stickstofffreien organischen Verbindungen wurde vorgeschlagen. Die Titration erfolgt in 50% acetonischer Lösung, um die Störung durch Wasserstoffperoxid auszuschalten.

     

Reactivity of electron-poor decamethyl-1,3-diboraruthenocene with sulfur and phosphorus compounds

Decamethyl-1,3-diboraruthenocene [(η⁵-C₅Me₅)Ru{η⁵-(CMe)₃(BMe)₂}] (1) reacts with cyclo-octasulfur in hexane to give [(η⁵-C₅Me₅){η⁵-(CMe)₃(BMe)₂}RuS] (3), which may also be obtained from 1 and propylene sulfide. 1 reacts with H₂S to form the ruthenathiacarboranyl complex [(η⁵-C₅Me₅)Ru{η⁴-(CMe)₃(BMe)₂S}] (6), for which a nido-structure is proposed. The isomeric compounds 3 and 6 have different stabilities: 3 loses sulfur and unexpectedly the closo-cluster [(η⁵-C₅Me₅)₂Ru₂H(CMe)₃(BMe)₂] (4) is formed with hydrogen bridging the basal and apical Ru centers. Reaction of 1 with carbonylsulfide (COS) yields the dinuclear ruthenium compound [(η⁵-C₅Me₅)Ru{η⁵-(CMe)₃(BMe)₂(S)(COBMe)}]₂ (7) in which two B-O groups bridge two ruthenium complexes. Its formation results from a complex reaction sequence: sulfur inserts into the diborolyl ring and the ligand CO forms an oxygen-boron bridge to a second molecule, followed by insertion of the carbonyl carbon into the double bond of the diboraheterocycle. Carbon disulfide reacts with 1 to give the dinuclear complex 8 with two CS₂ molecules connecting the ruthenium centers. When 1 and P₄ are heated in toluene, the sandwich 9 is obtained by formal insertion of a P-H group into the diborolyl ring of 1 and the triple-decker [{η⁵-(C₅Me₅)Ru}₂{μ-(MeC)₃P(MeB)₂} (10) is detected in the mass spectrum. The phosphaalkyne PCtBu inserts into 1 to give the ruthenaphosphacarborane [(η⁵-C₅Me₅)Ru{(CMe)₂(BMe)(PCtBu)(CMe)(BMe)}] (11) in high yield. Phosphanes react with 1 to give weak donor-acceptor complexes 1 · PH₂R (12) (R=Ph, H). The compositions of the compounds are deduced from spectroscopic and analytical data and are confirmed for 4 and 7 by X-ray structural analyses.