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A new mode of activation: The asymmetric diarylprolinol‐catalyzed α‐sulfenylation of β‐ketoesters provides the products in good‐to‐excellent enantioselectivities and yields. Studies suggest that the sterically bulky secondary amines activate β‐ketoesters through hydrogen bonding. Lg=leaving group.

3Thioformylindolizines undergo novel reductive coupling reaction in the presence of tributylphosphine to give E1,2bis3indolizinylethylenes in high yield. These reactions proceed via3indolizinylmethylene carbene intermediate and provide a new, stereoselective synthesis of the bis3indolizinylethylene derivatives highly.

1-Methyl-2-phenylindolizine-3-acetonitrile was unexpectedly obtained in the reaction of 1-methyl-2-phenylindolizine-3-thioaldehyde with cyanide ions. Its structure was determined by IR, 1H NMR, MS, elemental analyses, and X-ray crystallography. Colorless regular prism shaped crystals of C17H14N2crystallize in the space group C2/cwith cell dimensions a= 12.956(3) Å, b=10.516(2) Å, c= 20.429(4) Å, and α = 90°, β = 104.98(3)°, γ = 90°, V=2688.7(9) Å3, Dcalc=1.217 Mg/m3, and Z= 8.

An efficient two step route has been developed to synthesize pyrrolo2,1,5cdindolizine derivatives. The reaction sequence proceeds viapreparation of 3acyl5methylindolizines followed by an intramolecular condensation. The procedures were carried out under convenient conditions and gave the products in high yields. It could be expected to be used to prepare a broad range of potentially interesting pyrrolo2,1,5cdindolizine derivatives.

An oxidant promoted 1,3dipolar cycloaddition of benzimidazolium ylides to alkenes was developed for the preparation of 4Hpyrrolo1,2abenzimidazole derivatives in moderate yields under mild conditions. In the presence of a suitable oxidant, the most commercially available “normal” alkenes, instead of alkynes or “abnormal” alkenes, could be used as dipolarophiles successfully. Moreover, CrO3Et3N has been proved to be a more effective dehydrogenating reagent than MnO2or tetrakispyridine cobalt II dichromate TPCD in this procedure.

We describe here, for the first time, that 1cyano3benzoyl1,2,3,10btetrahydropyrrolo2,1aphthalazine 8, prepared by 1,3dipolar cycloaddition of 2phenacyl phthalazinium bromide 6a with acrylonitrile 7a, can be aromatized by tetrakispyridine cobalt II dichromate TPCD to give 1cyano3benzoylpyrrolo2,1αphthalazine 9a in good yield. Furthermore, a general and convenient onepot procedure for preparation of pyrrolo2,1αphthalazines 9ap was developed by 1,3dipolar cycloaddition of phthala zinium Nylides 6ac with alkenes 7ag in the presence of TPCD.

3-Chloro-3,6-dinitro-2,2-dimethyl-4-chromanone is the first 3-chloro-3-nitro-4-chromanone to be synthesized by nitrating its corresponding 4-chromanone at the 3 position and then chlorinating the nitration product. Its structure was determined by IR, NMR, MS and x-ray crystallography. It crystallizes as a pair of enantiomers with 2 molecules in the primitive triclinic space group P $$\overline 1$$ (#2) with a = 9.476(2), b = 10.906(3), c = 6.578(5) Å, and α = 101.08(3), β = 90.13(3), γ = 73.23(1)°, V = 637.7500 Å3, and Z = 2. The nitro group at the 6 position conjugates with the benzene ring. The pyranone ring has a half-chair conformation; the chloro group occupies the pseudoequatorial position, and the nitro group occupies the pseudoaxial position. The 2 and 3 positions are essentially antiperiplanar, minimizing steric interaction.

AbstractOligomers of p-phenylene oxides have been synthesized by coupling of substituted phenols and aryl bromides in the presence of cuprous chloride. The chain length varies from 2 to 5 phenyl rings functionalized at one end by an OH and OMe group and at the other end by an OH, OMe or NO2functions. The oligomers could be used in material science and as building blocks in supramolecular chemistry. Methods for chemoselective demethylation of methoxy groups were developed.

AbstractAromatization of Hantzsch 1,4-dihydropyridines (la-n) were promoted by tetrakis-pyridine cobalt (11) dichromate to yield corresponding pyridine derivatives (2a-n) in moderate to high yields (70-87%). The reaction was carried out under mild and convenient conditions.

AbstractIn the presence of tetrakispyridine cobalt dichromate (CoPy4(HCrO4)2), pyridinium ylides and α,β-unsaturated aldehydes or ketones undergo 1,3-dipolar cycloaddition reactions followed by in situaromatization to give 1-acyl substituted indolizines in moderate to good yields.

AbstractAnodic oxidation of a series 1,4-dihydropyridines were performed in acetonitrile-tetrabutylammonium perchlorate electrolyte solution at platinum electrode using controlled potential electrolysis. On the bases of electroanalytical results the electrochemical oxidation mechanism of 1,4-dihydropyridines could be designed ECEC process. As a result of two-electron oxidation corresponding pyridines were obtained in yields ranging from 85%–92%. The advantages of electrochemical synthesis of pyridine derivatives are simple reaction condition, low cost and of high purity products.

Twelve title compounds 6a-61, which could be reduced by enantioselective hydrogenation to give corresponding chiral acyclic Reissert compounds, were prepared conveniently in moderate to high yields (75-95%).

Fourteen 1,2,3-triaroylindolizines were prepared conveniently by oxidation of corresponding N-aracyl pyridinium or substituted pyridinium bromides with a versatile oxidant TPCD [(Py4Co(HCrO4)2, tetrakis-pyridino-cobalt (II) dichromate] in 12-42 % yields.

3-Nitro-2,6-bis(4'-benzo-15-crown-5)aminopyridine and its rubidium picrate complex were synthesized, and the first known example of a bis(crown ether) rubidium picrate intramolecular sandwich complex was obtained. The structure is confirmed by solid state studies: C39H44N7O19Rb·CH3OH·H2O, triclinic, P1. a = 11.481(4), b = 14.519(4), c = 15.960(6) Å, α = 63.28(3), β = 73.75(3), γ = 80.66(3)°, Dc = 1.53 g/cm3, Z = 2, and R = 0.091 for the 2350 observed reflections. The rubidium cation is intramolecularly sandwiched by ten oxygen atoms. The Rb-O bond lengths range from 2.849(12) Å to 3.02(2) Å. The picrate anion is linked by ionic interactions to the large cation.

AbstractN-(1-cyano-2-substituted phenylethyl) acetamides (4a-h) were synthesized by reduction of corresponding titled compounds 3a-hwith NaTeH. The procedure was general and convenient for preparation of benzyl substituted acyclic Reissert compounds without using phenylacetaldehydes as starting materials.

The preparation of a versatile oxidizing agent tetrakis-pyridino-cobalt (II) dichromate Py4Co(HCrO4)2 (TPCD) is presented and its structure is confirmed by x-ray crystal data. Alcohols, halides and amines are oxidized smoothly to their corresponding carbonyl compounds in good yields with TPCD.

The reaction of substituted cinnamonitriles with 4-hydroxycoumarin in water in the presence of triethylbenzyl-ammonium chloride affords 2-amino-4-aryl-4H,5H-pyrano [3,2-c] [1]benzopyran-5-one derivatives.

A short and facile synthesis of a series of 1,2-dihydroquiazolin-4(3H)-ones was accomplished in good yields via the novel reductive cyclisation of o-nitrobenzamides with aldehydes or ketones promoted by the TiCl4/Sm system. Structures were established on the basis of elemental analysis, IR, 1H NMR and confirmed by a single-crystal X-ray diffraction analysis. The advantages of our method are easily accessible starting materials, convenient manipulation and moderate to high yields.

The reaction of an aromatic aldehyde, isopropylidene malonate and 5,5-dimethyl-1,3-cyclohexanedione in water in the presence of triethylbenzylammonium chloride (TEBA) as catalyst affords a one-pot synthesis of 4-aryl-7,7-dimethyl-5-oxo-3,4,5,6,7,8-hexahydrocoumarin.

The intramolecular reductive cyclizations of o-nitrochalcones(1) induced by the TiCl4/Zn system were studied; 2-arylquinolines(2) and 5,6-dihydrobenz[c]acridines(4) were obtained in reasonable yields at room temperature conditions.

A short and facile synthesis of a series of 3-arylquinazolin-4(3H)-ones was accomplished in good yield via the intermolecular reductive coupling reaction of N-aryl-2-nitrobenzamide and triethyl orthoformate promoted by TiCl4/Sm.

The cyclodimerisation of α,β-unsaturated ketones induced by the TiCl4/Sm system was studied, cyclopentanol derivatives are prepared in good yields under neutral and mild conditions.

A novel approach to synthesize pyrrolo[1,2-a]quinoxalines was developed successfully by 1,3-dipolar cycloaddition of a quinoxalinium N-ylide to alkenes in the presence of MnO2under very convenient conditions and with moderate yields (40–52%).

Intermolecular 1,3-dipolar cycloadditions of 2-(2-phenylethenyl)pyridinium N-ylides (3a–d) with electron-deficient alkenes (5a–d) were carried out selectively in the presence of tetrakis-pyridine cobalt(II) dichromate to yield 5-(2-phenylethenyl)indolizines (6a–j) in moderate yields (48–63%).

A novel approach to synthesize pyrrolo[1,2-a]quinoxalines was developed successfully by 1,3-dipolar cycloaddition of a quinoxalinium N-ylide to alkenes in the presence of MnO2 under very convenient conditions and with moderate yields (40–52%).

Intermolecular 1,3-dipolar cycloadditions of 2-(2-phenylethenyl)pyridinium N-ylides (3a–d) with electron-deficient alkenes (5a–d) were carried out selectively in the presence of tetrakis-pyridine cobalt(II) dichromate to yield 5-(2-phenylethenyl)indolizines (6a–j) in moderate yields (48–63%).

A novel approach to synthesize pyrrolo[1,2-a]quinoxalines was developed successfully by 1,3-dipolar cycloaddition of a quinoxalinium N-ylide to alkenes in the presence of MnO₂ under very convenient conditions and with moderate yields (40–52%).

An efficient method is elaborated for the gold‐catalyzed reductive amination of aldehydes (I) and ketones (IV) with an equimolar amount of anilines in the presence of Hantzsch ester as reducing agent.

An efficient and convenient method to synthesize a new class of thiosemicarbazone derivatives (III) containing a thiazole moiety is reported.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

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