21456-99-5Relevant academic research and scientific papers
Phosphoramidates as Transient Precursors of Nitrogen-Centered Radical Under Visible-Light Irradiation: Application to the Synthesis of Phthalazine Derivatives
De Abreu, Maxime,Selkti, Mohamed,Belmont, Philippe,Brachet, Etienne
, p. 2216 - 2222 (2020)
Phosphoramidates are for the first time presented as efficient N-Centered Radical (NCR) precursors under visible-light irradiation. More precisely among this class of phosphorus-derived compounds, we studied the radical reactivity of phosphonohydrazones, under mild reaction conditions, which allowed the synthesis of a wide and diversified library of the scarcely reported phthalazine scaffold. Mechanistic investigations confirmed the formation of a NCR from these brand-new phosphonohydrazones (derivatived from phosphoramidates), which were further engaged in an intramolecular 6-exo-dig cyclization to provide phthalazines. Compared to other pre-activated moieties, the phosphoramidate group is self-immolative, thus enhancing its attractiveness for the C?N bond formation. (Figure presented.).
Carbon-carbon bond cleavage of α-hydroxybenzylheteroarenes catalyzed by cyanide ion: Retro-benzoin condensation affords ketones and heteroarenes and benzyl migration affords benzylheteroarenes and arenecarbaldehydes
Suzuki, Yumiko,Takemura, Yuki,Iwamoto, Ken-Ichi,Higashino, Takeo,Miyashita, Akira
, p. 199 - 206 (2007/10/03)
4-(α-Benzylα-hydroxybenzyl)quinazoline (4a) underwent retro-benzoin condensation catalyzed by cyanide ion to give deoxybenzoin (2a) and quinazoline (5a). Similarly, several nitrogen-containing heteroarenes (4, 9, 12, 16-19) having an α-hydroxybenzyl group at the α-position of the nitrogen underwent retro-benzoin type condensation to afford kelones (2) and heteroarenes (5). However, similar reaction of pyrazolopyrimidines (13, 14, 15) having an α-benzyl-α-hydroxybelzyl group resulted in benzyl migration, giving benzylpyrazolopyrimidines (8) and arenecarbaldehydes (3). Tetrabutylammonium cyanide (11, Bu4NCN) was a more effective cyanide ion donor than KCN (10). The retro-benzoin condensation was applied to the synthesis of 2-substituted quinazolines (38) from 2-chloro-4- aroylquinazolines (34), using the aroyl group as a protecting and electron- withdrawing group.
