ChemInform Abstract: PYRIDINIUM YLIDES. II. THE REACTION OF CARBANION‐MONOSUBSTITUTED 4‐PHENYLPYRIMIDINIUM YLIDES WITH ACTIVATED ACETYLENES

Abstract

Die Pyrimidinium‐ylide (I) reagieren mit den Acetylencarbonsäureestern (II) zu den Pyrrolopyrimidinen (III).

New N-bridgehead heterocyclic compounds. II. Carbamoyl-substituted azaindolizines

“…In our previous works [7][8][9][10][11][12] many similar 1,3-dipolar cycloaddition reactions were described.…”

A new synthesis of pyrrolo[1,2-c]quinazoline from quinazolinium N-ylides: a re-investigation

“…The first one is a simple [3+3] cycloaddition reaction of two molecules of cycloimmonium-ylides as 1,3-dipoles leading to pyrazine derivatives, [8][9][10][11][12] sometimes reversible. 8,10 The second one implies carbene intermediates and leads to dimers with an ethylene double bond. 3a,13 While extending our work on the synthesis of pyrrolo[1,2-c]quinazolines of this type, we obtained the new inactivation compounds 3i,j by heating the corresponding quinazolinium salts in 1,2-epoxybutane (Scheme 2).…”

New Substituted Indolizines by 1,3-Dipolar Cycloaddition Reactions I. 7-tert-Butylindolizines

“…Carbanion monosubstituted pyridinium N-ylides are generally unstable compounds, and thus are generated in situ. This can be done by treatment of pyridinium salts with a base, such as triethylamine in organic solvents or with an aqueous solution of inorganic base, or by using an epoxide as the reaction medium [24][25][26][27][28]. In the first case, the N-ylide generation mechanism is direct, consisting of the deprotonation of the pyridinium salt by the base.…”