The initially formed N-phenylnitrone-intermediates are converted by a tandem-reaction (cycloaddition, Cope rearrangement, retro-Michael addition, and indolization) to 2-vinylindoles . Thus these indoles can be synthesized simply and stereoselectively in a one-pot reaction from N-phenylhydroxylamine , aldehydes , and electron-deficient allenes .
Berberine chloride (1) upon treatment with NaOAc-Ac2O yields naphthalene derivatives 4 and 5 In like fashion, 8 gives naphthalene 10; isoquinoline methiodide leads to β-naphthyl acetate; and 12 provides 14. The reaction has been extended to the 3-carbonyl pyridinium series where 3-acetylpyridine methiodide and 3-pyridinecarboxaldehyde methiodide furnish lactones 16 and 17, respectively. All these transformations
Constitutional dynamic systems of ionic and molecular liquids
作者:Morgan D. Soutullo、Richard A. O’Brien、Kyle E. Gaines、James H. Davis
DOI:10.1039/b901899a
日期:——
The ionic liquids N-methylpyridinium-2-carboxaldehyde Tf2N− and N-methylpyridinium-3-carboxaldehyde Tf2N− form readily-reversible covalent bonds with protic nucleophiles, creating all-liquid constitutionally dynamic materials.
A short synthetic route to 16-demethyleneervitsine (6), based on the nucleophilicaddition of 2-acetylindoleenolates to N-alkyl-β-acylpyridinium salts and further acid cyclization of the resulting 1,4-dihydropyridine intermediates, is reported.
Synthesis of 3,5-diacyl-4-phenyl-1,4-dihydropyridines
作者:M.-Lluïsa Bennasar、Cecília Juan、Joan Bosch
DOI:10.1016/s0040-4039(98)02084-x
日期:1998.12
via a regio- and chemoselective addition of Ph2Cu(CN)Li2 to β-substituted N-alkylpyridinium salts, followed by acylation of the intermediate 1,4-dihydropyridines with trichloroacetic anhydride and subsequent haloform-type reaction. A similar sequence using an N-silylpyridinium salt and PhMgBr allows the preparation of the corresponding N-unsubstituted dihydropyridines.