CONVENIENT PREPARATIONS OF DIETHYL [(ACYLAMINO)METHYL]PHOSPHONATES, 2-AZABUTADIENES, AND ISOQUINOLINES FROM A 1,2-MONOAZABISYLIDE EQUIVALENT

Diethyl [(triphenylphosphoranylidene)amino]methyl]phosphonate (4), prepared in situ by treatment of 1-[[(triphenylphosphoranylidene)amino]methyl]benzotriazole (betmip 6) with diethyl phosphite anion,is converted by treatment with butyllithium into the corresponding carbanion 5. Carbanion 5, the first example of a 1,2-monoazabisylide equivalent, provides a versatile synthetic method to introduce the C=NC=C structural unit, as illustrated by convenient preparations of 1,4-diaryl-2-azabutadienes, 1,1,4,4-tetraaryl-2-azabutadienes, diethyl [(acylamino)methyl]phosphonates, and isoquinolines.