Synthesis of carbo- and heterobiaryls by intermolecular radical addition of aryl bromides onto aromatic solvents

Tris(trimethylsilyl)silane (TTMSS) and azabisisobutyronitrile (AIBN) promoted the intermolecular arylation of aryl and heteroaryl bromides onto aromatic solvents under thermal conditions via a radical pathway.Financial support by the Comisión Interministerial de Ciencia y Tecnologı́a (CICYT, project BQU2001-1508) and a grant to one of us by the Universidad de Alcalá (A.N) are gratefully acknowledged

Pyridinium N-2´-pyridylaminide: synthesis of 3-aryl-2-aminopyridines through an intramolecular radical process

Tris(trimethylsilyl)silane (TTMSS) and azobisisobutironitrile (AIBN) promote the intramolecular heteroarylation of arenesulfonamides with pyridyl radicals under thermal conditions. The arenesulfonamides are easily prepared from pyridinium N-2′-pyridylaminide. The heteroarylation process involves pyridyl radical cyclization and ipso substitution.Financial support by the Comisión Interministerial de\ud Ciencia y Tecnología (CICYT, project BQU2001-1508)\ud and two grants, by the Universidad de Alcalá (A. S.) and\ud by Ministerio de Educación y Ciencia (Spain) (A. N.) are\ud gratefully acknowledged

Pyridinium N-2 '-pyridylaminide: radical cyclization in the synthesis of annulated 2-aminopyridines

The synthesis of annulated 2-aminopyridines by intramolecular radical pyridylation of the appropriate substrates, obtained from pyridinium N-2'-pyridylaminide, can be performed using TTMSS and AIBN.Financial support by the CICYT (Project CTQ2005-08902/BQU) and two grants, by the Universidad de Alcalá\ud (A.S.) and by Ministerio de Educación y Ciencia\ud (Spain) (A.N.) are gratefully acknowledged

Pyridinium N-2´-pyridylaminide: radical cyclization for the synthesis of benzonaphthyridine derivatives

The synthesis of benzonaphthyridine derivatives that incorporate a 2-aminopyridine moiety can be performed by intramolecular radical pyridylation of the appropriate substrates, obtained from pyridinium N-2¿-pyridylaminide, using TTMSS and AIBN.Financial support from the CICYT (project CTQ2005-\ud 08902/BQU) and two grants from the Universidad de Alcala\ud (A.S) and the Ministerio de Educacion y Ciencia (Spain)\ud (A.N.) are gratefully acknowledged

N-azinylpyridinium N-aminides: tandem reactions with alpha-halocarbonyl derivatives and analogs

Pyridinium-N-(2´-pyridyl)aminide was reacted with different α-halocarbonyl derivatives and related compounds. The method allows an easy preparation of several heterocyclic building blocks, all including the 2-aminopyridine moietyAuthor wish to thank C.I.C.Y.T. for financial support (Project PM97-0074) and the Universidad de Alcalá for a grant to one of us (R.R.)

Selective palladium-catalyzed amination of the heterocyclic core of variolins

A new and selective palladium-catalyzed amination of the pyrido[3′,3′:4,5]pyrrolo[1,2-c]pyrimidine nucleus, the heterocyclic core of the variolin alkaloids, is described. The method allows the introduction of amino and aryl- and alkylamino substituents on the C9 position in advanced precursors of variolin B and deoxyvariolin.We acknowledge financial support from the Spanish Ministerio de Educación y Ciencia (project CTQ2005/011060), Comunidad de Madrid (CAM) and Universidad de Alcalá (UAH) (project CAM/UAH-2005/044) and a grant (A.B.) from the Ministerio de Educación y Ciencia

An easy preparation of pyridinium N-heteroarylaminides

A synthesis of substituted pyridinium N-heteroarylaminides, e.g., I, is reported. Heteroaryl chlorides underwent nucleophilic substitution with N-aminopyridinium iodide to give the corresponding substituted pyridinium N-heteroarylaminides in good yields. [on SciFinder(R)]Differently substituted pyridinium N-heteroarylaminides have been prepared in one step with good yield from N-aminopyridinium iodide and the corresponding heteroaryl chloride.The authors wish to thank the Ministerio de Ciencia y Tecnología (projects CICYT-2FD97-1248 and BQU2001-1508) for financial support, and the Ministerio de Educación y Cultura for a studenship (M.J.R.)

Pyridinium N-(2'-azinyl)aminides: Regioselective synthesis of 2-alkylaminoazines

The regioselective alkylation of pyridinium-N-(2'-azinil)aminides with alkyl halides under mild conditions is described. The alkylation, combined with a reduction of the N-N bond, allows an easy preparation of 2-alkylaminoazines.The authors wish to thank the Comision Interministerial de Ciencia y Tecnologı́a (C.I.C.Y.T.) (Project PM97-0074) and the Vicerrectorado de Investigación, Universidad de Alcalá for financial support (Project E014/97)

Palladium-mediated C-N, C-C, and C-O functionalization of azolopyrimidines: a new total synthesis of variolin B

A new total synthesis of the alkaloid variolin B is achieved by a selective and sequential palladium-mediated functionalization of a\ud trihalo-substituted pyrido[30\ud ,20\ud :4,5]pyrrolo[1,2-c]pyrimidine. This intermediate is obtained by a new heterocyclization reaction between\ud an appropriate bromomethyl azaindole and N-tosylmethyl dichloroformimide. The methodology may be effective for the synthesis of\ud some analogs by substitution on the relatively unexplored C4 and C9 positions of the alkaloid.The authors acknowledge financial support from the\ud Spanish Ministerio de Educación y Ciencia (project\ud CTQ2005/011060/BQU), Comunidad de Madrid (CAM),\ud and Universidad de Alcalá (UAH) (project CCG-UAH/\ud SAL-0660) and a grant from the Ministerio de Educación\ud y Ciencia (A.B.)

Halogenation of pyridinium-N-(2'-pyridyl)aminide: an easy synthesis of halo-2-aminopyridines

The regioselective halogenatmn of pyrldmium-N-(2’-pyridyljaminide 1 with N-chloro,\ud bromo or iodosuccinimtde under mild conditions IS described. The method, combined with a\ud reductmn of the N-N bond, allows an easy preparation of 5-h& and 3,5-dihalo-Z-aminopyridines 4The authors wish to thank the Comisión Interministerial de Ciencia y Tecnología (C.I.C.Y.T.) for financial support (Project PB90-0284) and to Lilly S. A. for one studentship (C.B.