Several 3-carbonyl (1–26), 3-acyl (27–52), and 3-carboxyhydrazido (53–58) coumarins have been synthesized in high yields (72–99%) and tested in vitro for their human monoamine oxidase A and B (hMAO-A and hMAO-B) inhibitory activity. Different substituents on the coumarin nucleus were evaluated for their effect on biological activity and isoform selectivity. Substitution at position C7 of the 3-ethyl
arylation and aroylation of coumarins with glyoxals in a metal-free manner is presented. The aryl glyoxal is for the first time recognized to serve as an aryl surrogate in addition to its role as an aroyl transfer reagent via a simple switch in reaction conditions. The approach accommodates a broad substrate scope and high yields of the two types of cross-coupling reactions starting from identical starting
cobalt-catalyzed C–H bond activation of coumarins with aryl halides or pseudohalides and carbon monoxide insertion to give various 3-aroylcoumarin derivatives is described. It is the first time that CO as C1 feedstock is used as the coupling partners in cobalt-catalyzed regioselective coumarin C–H functionalization reactions. Upon activation with manganese powder, the Co catalyzes the C–H bond activation
Condensation of α-Aroylketene Dithioacetals and 2-Hydroxyarylaldehydes Results in Facile Synthesis of a Combinatorial Library of 3-Aroylcoumarins
作者:H. Surya Prakash Rao、S. Sivakumar
DOI:10.1021/jo061372e
日期:2006.11.1
facile, convenient, efficient, and high yielding synthesis of a combinatoriallibrary of 3-aroylcoumarins has been developed by the condensation of easily available α-aroylketene dithioacetals (AKDTAs) and 2-hydroxybenzaldehydes (salicylaldehydes)/2-hydroxy-1-naphthaldehyde in the presence of catalytic amount of piperidine in THF reflux. The condensation of ferrocene derived α-aroylketene dithioacetal
The first highly enantioselective construction of chiral cyclopropa[c]coumarins was described. Using commercially available (bis)cinchona alkaloid (DHQ)2PYR as the chiral Lewis base catalyst, together with Cs2CO3 as the achiral base, the reaction of a series of coumarin-3-carboxylate and 3-benzoyl coumarins with tert-butyl 2-bromoacetate could give rise to the corresponding cyclopropa[c]coumarins bearing
描述了手性环丙烷[ c ]香豆素的第一个高度对映选择性的结构。使用市售的(bis)金鸡纳生物碱(DHQ)2 PYR作为手性Lewis碱催化剂,以及Cs 2 CO 3作为非手性碱,一系列香豆素3-羧酸盐和3-苯甲酰基香豆素与叔丁基的反应- 2-溴乙酸丁酯可产生相应的带有三个连续手性立体中心的环丙烷[ c ]香豆素,分别在83-93%ee和90-97%ee处。建议该反应通过原位产生的内铵盐中间体进行。