Synthesis of Functionalized Pyridazin-3(2<i>H</i>)-ones via Nucleophilic Substitution of Hydrogen (S<sub>N</sub>H)
作者:Tom Verhelst、Stefan Verbeeck、Oxana Ryabtsova、Stefaan Depraetere、Bert U. W. Maes
DOI:10.1021/ol102703w
日期:2011.1.21
Reaction of 2-benzyl-5-halopyridazin-3(2H)-ones (3) with Grignard reagents followed by quenching with electrophiles unexpectedly yielded 4,5-disubstituted pyridazin-3(2H)-ones instead of 5-substituted pyridazin-3(2H)-ones. These reactions represent the first examples of cine substitution in which the anionic σH-adduct is quenched by electrophiles (other than a proton) before elimination takes place
2-苄基-5-卤代哒嗪-3(2 H)-ones(3)与Grignard试剂反应,然后用亲电试剂猝灭,意外地得到4,5-二取代哒嗪-3(2 H)-ones代替5-取代哒嗪-3(2 H)-ones。这些反应代表,其中所述阴离子σ电影取代第一实施例ħ -adduct通过亲电(不同于质子)消除猝灭之前发生。对反应机理的深入了解导致了2-苄基哒嗪-3(2 H)-one(7)和2-苄基-6-氯哒嗪-3(2 H)-one(9)转化为相应的C-4烷基和芳基衍生物(当Br 2被用作亲电试剂时)。