Efficient, highly regioselective fries rearrangements of methyl 3-(2-acyloxy-4-methoxyphenyl)propanoates: The first total syntheses of the linear acylated coumarins geijerin and dehydrogeijerin.
作者:Nicholas Cairns、Laurence M. Harwood、David P.pp]Astles
DOI:10.1016/s0040-4039(00)80285-3
日期:1988.1
Aluminiumchloridecatalysed para-Fries rearrangement of methyl 3-(2-acyloxy-4-methoxyphenyl)propanoates (5)in nitromethane furnishes the corresponding 5-acylated products (6) cleanly and in high yield. The rearrangement products may be converted into 6-acyl-7-methoxycoumarins (2) including the naturally occurring geijerin (2a) and dehydrogeijerin (2b).
7,8-Disubstituted- but not 6,7-disubstituted coumarins selectively inhibit the transmembrane, tumor-associated carbonic anhydrase isoforms IX and XII over the cytosolic ones I and II in the low nanomolar/subnanomolar range
作者:Alfonso Maresca、Andrea Scozzafava、Claudiu T. Supuran
DOI:10.1016/j.bmcl.2010.10.094
日期:2010.12
Two series of disubstituted coumarins incorporating ether and acetyl/propionyl moieties in positions 6,7- and 7,8- of the heterocyclic ring were synthesized investigated for the inhibition of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). All these coumarins were very weak or ineffective as inhibitors of the housekeeping, offtarget isoforms CA I and II. The 6,7-disubstituted series showed ineffective inhibition also for the transmembrane tumor-associated isoforms CA IX and XII, whereas the corresponding isomeric 7,8-disubstituted coumarins showed nanomolar/subnanomolar inhibition of CA IX/XII. The nature and position of the groups substituting the coumarin ring in the 7,8-positions greatly influenced CA inhibitory properties, with C1-C4 alkyl ethers being the most effective inhibitors. (C) 2010 Elsevier Ltd. All rights reserved.
Paradkar, Madhusudan V.; Kulkarni, Madhuri S.; Kulkarni, Sanjeev A., Journal of Chemical Research - Part S, 1995, # 6, p. 262 - 263
作者:Paradkar, Madhusudan V.、Kulkarni, Madhuri S.、Kulkarni, Sanjeev A.、Godbole, Himanshu M.