89840-16-4Relevant academic research and scientific papers
An unexpected rearrangement-hydration reaction sequence of 2H-chromenes to dihydrochalcones under catalysis of HAuCl4
Maiti, Gourhari,Kayal, Utpal,Karmakar, Rajiv,Bhattacharya, Rudraksha N.
, p. 6321 - 6325,5 (2012/12/12)
2-Aryl-2H-chromenes in aqueous DCM medium under catalysis of HAuCl 4 are converted into 3-(2-hydroxyaryl)-1-arylpropan-1-ones through hydration-rearrangement reaction sequence in very good yield. The key step probably involves the [1,5] hydride shift followed by the hydrolysis under the reaction condition. The notable advantages of this method are operational simplicity and ease of isolation of products and also provide a pathway to convert the chalcone into DHCs with the transposition of carbonyl group. 2012 Elsevier Ltd. All rights reserved.
Rhodium-catalyzed cyclopropanations of 2-aryl-2H-chromenes with dialkyl malonate esters. A comparison of α-diazo derivatives and phenyliodonium ylides
Stokes, Sean,Mustain, Rachel,Pickle, Lydia,Mead, Keith T.
supporting information; experimental part, p. 3890 - 3893 (2012/09/08)
Rhodium-catalyzed reactions of 2-aryl-substituted 2H-chromenes with α-diazo esters prepared from dimethyl and tert-butyl methyl malonates were investigated, and the results were compared with reactions carried out with phenyliodonium ylides prepared from the same esters. The phenyliodonium ylide prepared from dimethyl malonate was found to give superior yields of cyclopropane products compared to the corresponding α-diazo equivalent. However, this result was reversed with tert-butyl methyl malonate when Rh 2(S-TBSP)4 was used to decompose the diazo compound. All reactions gave 1,1-cyclopropane diesters as single diastereomers.
Synthesis and antimalarial evaluation of novel benzopyrano[4,3-b]benzopyran derivatives
Devakaram, Ruth,Black, David Stc.,Andrews, Katherine T.,Fisher, Gillian M.,Davis, Rohan A.,Kumar, Naresh
experimental part, p. 5199 - 5206 (2011/10/09)
7-Methoxyflavenes and 5,7,8-trimethoxyflavenes were found to undergo stereoselective acid-catalyzed rearrangement to generate the benzopyrano[4,3-b]benzopyran ring system present in the natural product, dependensin. Dependensin and its analogs were subjected to antimalarial growth inhibition assays against Plasmodium falciparum and found to have IC 50 values ranging between 1.9 and 3.9 μM.
Enantioselective synthesis of flavan-3-ols using a mitsunobu cyclization
Krohn, Karsten,Ahmed, Ishtiaq,John, Markus
experimental part, p. 779 - 786 (2009/09/06)
The synthesis of four flavan-3-ols with different substitution patterns and electron densities has been achieved in high stereo- and regioselectivity by a one-step Mitsunobu reaction from the corresponding diols, which were prepared by enantioselective Sharpless dihydroxylation of suitable olefins. The six-membered flavan-3-ols were the only cyclization products and the theoretically possible formation of five-membered rings during the Mitsunobu cyclization was not observed. The flavanols are important starting materials for the synthesis of dimers such as the procyanidins or other coupling products such as the flavan part of the potent DNA polymerase β inhibitor myristinin A. The enantioselectivities of both the Sharpless dihydroxylation and the Mitsunobu cyclization steps were monitored by chiral HPLC. Georg Thieme Verlag Stuttgart New York.
