Ren Hongjun, Knochel Paul
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377, München, Germany.
Chem Commun (Camb). 2006 Feb 21(7):726-8. doi: 10.1039/b515168f. Epub 2005 Dec 23.
A tosyloxy substituent in position 2 allows a highly regioselective Br/Mg exchange reaction on 3,5-dibromopyridine derivatives using iso-PrMgCl.LiCl. The resulting functionalized pyridylmagnesium reagents react with various electrophiles in position 3. Acylated pyridines of this type can be readily converted into pyrazolo [3,4-b] pyridines.
2位上的对甲苯磺酰氧基使得3,5-二溴吡啶衍生物能够使用异丙基氯化镁·氯化锂进行高度区域选择性的溴/镁交换反应。所得的官能化吡啶基镁试剂在3位与各种亲电试剂反应。这种类型的酰化吡啶可以很容易地转化为吡唑并[3,4-b]吡啶。
