Nitriles in Heterocyclic Synthesis: Novel Synthesis of Pyridazine Derivatives

1,2,4-Triazine Chemistry Part I: Orientation of cyclization reactions of functionalized 1,2,4-triazine derivatives

“…The Kabachnik-Fields reaction using 3,4-diamino-6-methyl-1,2,4-triazin-5(4H)-one (146), acetaldehyde and diethyl phosphite in THF in the presence of sodium hydride as a catalyst led to only one isomer of 1,2,4-triazino [4,3-b] [1,2,4,5]triazaphosphinine derivative 148. The reaction occurred by condensation of NH2 at position 4 that is more basic than NH2 at position 3, with acetaldehyde followed by addition of diethyl phosphite then cyclization by removing one molecule of ethanol (Scheme 44) [2].…”

“…Furthermore, many heterocyclic systems bearing 1,2,4-triazines are found to exhibit remarkable pharmacological effects [1][2][3][4][5]. In search for new anti-HIV and anticancer agents, some additional heterocyclic moieties were incorporated in the 1,2,4-triazine nucleus via the interaction between functionalized 1,2,4-triazines with various nucleophilic and electrophilic reagents in different media [6][7][8][9][10][11][12].…”

A new approach for the synthesis of bioactive heteroaryl thiazolidine-2,4-diones

“…11,12 In general, chromones are known as useful building blocks in organic synthesis due to the active center at position 2. This center is very reactive towards Michael addition of nucleophiles 13,14 with opening of the γ-pyrone ring followed by a new Vol. 22, No.…”

Arylhydrazonals as aldehyde components in Baylis-Hillman reaction: synthesis of 5-hydroxy-2,3,4,5-tetrahydropyridazine-4-carbonitrile and 6,7,8,8a-tetrahydrocinnolin-5(1H)-one

“…[1][2][3][4][5][6][7][8][9][10] In the past our group could successfully utilitized arylhydrazonals as precursors to pyridazines and pyrazoles with unique substitution pattern. [11][12][13][14][15][16] …”