Arylhydrazonals as the aldehyde component in Baylis-Hillman reactions
Arylhydrazonals were added to acrylonitrile or methyl vinyl ketone in the presence of DABCO or benzotriazole to yield the intermediate Baylis-Hillman adduct that cyclized under the reaction conditions with water elimination to yield dihydropyridazines. A pyridazine reacted with DMAD to yield a pyridine via a [4+2] Diels-Alder addition followed by retro Diels-Alder elimination of methylene aniline. Two pyridazines were condensed with DMFDMA to yield the corresponding enaminones that reacted with NH2NH2 to afford the pyrazolylpyridazines.
Al-Awadi, Nouria A.,Ibrahim, Maher R.,Abdelhamid, Ismail A.,Elnagdi, Mohamed H.
p. 8202 - 8205
(2008/12/22)
Efficient synthesis of 3-aroylcinnolines from aryl methyl ketones
An efficient synthesis of 3-aroylcinnolines starting from the appropriate aryl methyl ketones is described. The latter were converted in two steps to the corresponding 3-oxo-3-aryl-2-arylhydrazonopropanals, which upon acid catalyzed cyclization in conc. s