A new method of preparing 1, 2, 4-triazole carboxylic-3 acids

A new convenient method of preparing 1, 2, 4-triazole carboxylic acids-3 is worked out. Aminoguanidine bicarbonate and oxalic acid give 5-amino-1, 2, 4-triazole carboxylic acid-3, and this is converted, via the diazotriazole carboxylic acid and treatment of the latter with methanol, to 1, 2, 4-triazole carboxylic-acid-3.     

A new method for the synthesis of n-alkyl-4-piperidones

Summary A new method, based on the reaction of the methiodides of N-methyl-4-piperidones with primary amines, was proposed for the synthesis of N-alkyl-substituted 4-piperidones.     

Reaction of 4-methyl, 4-phenyl, and 4-hydrogen substituted 1-lithio-1,3-butadienes with aldehydes: preparation of multiply substituted cyclopentadienes

Reaction of aldehydes with 1-lithio-1,3-butadiene reagents possessing a methyl substituent, a phenyl substituent or a hydrogen at position 4 of the butadienyl skeletons was studied. Polysubstituted cyclopentadiene derivatives were obtained in high yields upon hydrolysis using strong acidic solution. Reaction mechanism study revealed that these cyclopentadienes were formed via an acid-promoted cyclization of conjugated dienols. Thus, stereodefined all-cis substituted dienols or a wide diversity of substituted cyclopentadienes can be obtained from the same 1-lithio-1,3-butadiene reagent and aldehyde by adjusting the hydrolysis conditions.     

A New Synthetic Method of Highly Substituted Cyclopentadienes from α,β-Unsaturated Alkynones

Promoted by samarium diiodlde in THF, the α, β-unsaturated alkynones were reduced to afford intermolecular reductive cou-pling products. The multiply substituted cyclopentadienes were prepared conveniently in good yields.     

The preparation of 4-alkylated derivatives of apopinene

Grignard reagents coupling with bromo-apopinene, which was prepared by NBS treatment of apopinene, leads to 4-alkylated derivatives of apopinene in high yields. Of particular interest is the convenient preparation of trans δ-pinene. The stereochemistry of these new compounds was established on the basis of NMR considerations.     

A new method for alkylating isoquinolinium salts at the 4 position

Alkylation and acylation of 2,3-dimethylisoquinolinium iodide at position 4- may be carried out in alkaline aqueous acetone. Presumably 1-acetonyl-2,3-dimethyl-1,2-dihydroisoquinoline is an intermediate. Lower yields were obtained in similar reactions with 2-methylisoquinolinium iodide.     

A new method for the synthesis of H(4)-BINOL

A method amenable to the gram scale synthesis of (R)-H 4-BINOL, a derivative of (R)-BINOL and ligand of interest in asymmetric catalysis, is described. The key step is the net partial hydrogenation of (R)-BINOL made possible by prior bis-etherification of the parent BINOL.     

4-甲氧基-2,3,5-三甲基吡啶的合成新方法

以2，3，5-三甲基吡啶为原料，经氧化，硝化，甲氧基化，脱离四步反应合成 4-甲氧基-2，3，5-三甲基吡啶，总收率76%，其结构经IR，~1H NMR，~(13)C NMR 确证。     

A new method for the preparation of 2,3-cycloalkeno-5,6-cycloalkeno-4H-pyran-4-ones

Several 2,3-cycloalkeno-5,6-cycloalkeno-4H-pyran-4-ones, such as 2,3,5,6-bicyclopenteno-4H-pyran-4-one and 1,2-dihydronaphtho[3,4-b]cyclopenteno[1,2-e]-4H-pyran-4-one, were synthesized conveniently by the reaction of a cyclic ketone enamine and diacylchloride. This reaction allows a new method for preparation of these compounds, which may be the precursors for the synthesis of some useful heterocycles.     

A new method for preparing （2Z, 4Z, 6Z）-diethyl-4,5- oxepinedicarboxylates and some 1H-azepine analogues

A new method for preparing (2Z, 4Z, 6Z)-4,5-diethyloxepinodicarboxylate by one-step is described. The synthesis of several oxepines and azepines derivatives was carried out by the reaction of substituted furans or pyrroles with diethyl acetylenedicarbox-ylate in boiling toluene. The effect factors for this reaction were discussed and reaction condition was optimized.     

Synthesis and fluxional behaviour of new “heavy fluorous” cyclopentadienes

The new “heavy fluorous” cyclopentadienes C₅H_6−n[M(C₂H₄C₆F₁₃)₃]_n (M = Si, n = 1 (3); n = 2 (4) and M = Sn, n = 1 (10)) were synthesized by reaction of cyclopentadienyl lithium with BrSi(C₂H₄C₆F₁₃)₃ (2) or commercial BrSn(C₂H₄C₆F₁₃)₃. Fluorous cyclopentadienes prepared in this manner contain three or six C₆F₁₃ groups, which significantly increase their solubility in perfluorinated solvents. They also provide intermediates for titanium complexes suitable for fluorous biphase catalysis. All three isomers of silylcyclopentadienes 3 and 4 were identified and fully characterized by two dimensional NMR spectroscopy, which was performed at low temperature. The allylic isomers 3a and 4a undergo degenerate metallotropic rearrangement. This fluxional behaviour was compared with the behaviour of previously prepared cyclopentadienes 6 and 7 (C₅H_6−n[SiMe₂(C₂H₄C₈F₁₇)]_n where n = 1, 2, respectively). The presence of allylic isomers 6a and 7a was further confirmed by Diels-Alder cycloaddition of the strong dienophile tetracyanoethylene (TCNE), providing compounds 8 and 9.     

The reactions of perfluoroalkanesulfinates: II. A new method for the synthesis of N,N-bisperfluoroalkylhydroxylamine1

The reaction of sodium or silver perfluoroalkanesulfinate with nitric acid, nitrous acid or nitrogen dioxide in aqueuos solution gave a moderate yield of N, N-bisperfluoroalkylhydroxylamine accompanied by perfluorocarboxylic acid, amide and nitrosoperfluoroalkane.     

A new method for the synthesis ofN,N′-thiobisamines

Reaction of secondary amines (morpholine and piperidine) with sulfur and iodine affordedN,N′-thiobisamines in good yields. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1891–1892, October, 1997.