A New Synthetic Method for Haloalkyl Carboxylic Esters from the Radical Ring Cleavage of Cyclic Acetals with Haloform
作者:Lin Hai-xia、Xu Liang-heng、Huang Nai-ju
DOI:10.1080/00397919708005032
日期:1997.1
Abstract A one-pot reaction of cyclicacetals with haloform catalyzed by AIBN(2,2′-azobisisobutyronitrile) provides a novel convenient way to prepare directly haloalkyl carboxylic esters in good yields.
Clear cut: For the title reaction, O2, the ideal oxidant, was used as the only oxidizing reagent. The dimer intermediate (see scheme) and isotopic labeling control experiments with 18O2 partially disclosed the reaction mechanism.
清晰:对于标题反应,使用理想的氧化剂O 2作为唯一的氧化剂。用18 O 2进行的二聚体中间体(参见方案)和同位素标记对照实验部分揭示了反应机理。
Synthesis and Activity Against HBV of Novel <i>Tetra-</i>Seconucleoside Analogues of Dyphlline Having the Acyclic Chains of ACV and HBG
作者:El Sayed H. El Ashry、Laila F. Awad、Nagwa Rashed、Adel AbdelRahman、Hana A. Rasheed
DOI:10.1080/15257770701845329
日期:2008.2.8
Selectivealkylation of dyphylline (1) with (2-acetoxyethoxy)methyl bromide (2a) or 4-acetoxybutyl bromide (2b) afforded 3′-O-[(acetoxyethoxy)methyl]dyphylline (3a) and 3′-O-(4-acetoxybutyl)-dyphylline (3b), respectively. A trans esterification process rather than alkylation of the dihydroxy-propyl side chain in 1 had taken place during the reaction with 2-p-toluoyloxy)ethyl chloride (5) to afford
An effective method for the construction of esters from acyl chloride and halohydrocarbon using Cs2CO3 as an oxygen source was achieved for the first time. The methodology has a wide scope of substrates and can be scaled up. The study of a preliminary reaction mechanism demonstrated that the 0 in the products comes from Cs2CO3 and this esterification proceeds through a free radical reaction. It was also found that CO2 can also be used in this esterification reaction as an oxygen source.
SUZUKI, HITOMI;PADMANABHAN, SEETHARAMAIYER;OGAWA, TAKUJI, CHEM. LETT.,(1989) N, C. 1017-1020