Facile Approach for the Synthesis of 2,3,4,9-Tetrahydro-1<i>H</i>-xanthen-1-ones and 8,9,10,12-Tetrahydro-11<i>H</i>-benzo[<i>a</i>]xanthen-11-ones via Trapping of <i>o</i>-Quinone Methides
作者:Vitaly A. Osyanin、Elena A. Ivleva、Yuri N. Klimochkin
DOI:10.1080/00397911.2010.545164
日期:2012.6.15
Abstract An efficient, simple synthesis of 2,3,4,9-tetrahydro-1H-xanthene-1-ones and 8,9,10,12-tetrahydro-11H-benzo[a]xanthen-11-ones is reported by one-pot condensation of 3-dimethylamino-2-cyclohexen-1-ones with hydroxybenzyl alcohols, phenol, and 2-naphthol Mannich bases or their quaternized derivatives. The mechanism of the reaction is believed to involve the formation of the o-quinone methide
Total synthesis of ()-xyloketal D and its enantiomer Confirmation of absolute stereochemistry
作者:Jeremy D Pettigrew、Rebecca P Freeman、Peter D Wilson
DOI:10.1139/v04-138
日期:2004.11.1
The total synthesis of ()-xyloketal D and its enantiomer have been achieved by the reaction of an ortho-quinone methide with (4R)- and (4S)-4,5-dihydro-2,4-dimethylfuran via a diastereoselective inverse electron demand DielsAlderreaction. This total synthesis confirmed the absolute stereochemistry of the natural product. The ortho-quinone methide was generated by reaction of an appropriately functionalized
The chalcone skeleton (1,3-diphenyl-2-propen-1-one) is a unique template that is associated with various biological activities. We synthesized Mannich bases of heterocyclic chalcones (9-47) using a one-step Claisen-Schmidt condensation of heterocyclic aldehydes with Mannich bases of acetophenones, and tested the target compounds for cytotoxicity against three human cancer cell lines (prostate, PC-3; breast, MCF-7; nasopharynx, KB) and a multi-drug resistant subline (KB-VIN). Out of the 39 chalcones synthesized, 31 compounds showed potent activity against at least one cell line with IC50 values ranging from 0.03 to 3.80 mu g/mL. Structure-activity relationships (SAR) are also discussed. (C) 2008 Elsevier Ltd. All rights reserved.
Reactions of <i>o</i>-Quinone Methides with Pyridinium Methylides: A Diastereoselective Synthesis of 1,2-Dihydronaphtho[2,1-<i>b</i>]furans and 2,3-Dihydrobenzofurans
作者:Vitaly A. Osyanin、Dmitry V. Osipov、Yuri N. Klimochkin
DOI:10.1021/jo400621r
日期:2013.6.7
A simple, general route to the 1,2-dihydronaphtho[2,1-b]furans and 2,3-dihydrobenzofurans substituted at C-2 by an acyl or aryl group, starting from phenolic Mannich bases and pyridinium ylides, has been developed. The mechanism of the reaction is believed to involve the formation of the o-quinone methide intermediate, Michael-type addition of the ylide to the o-quinone methide, followed by intramolecular nucleophilic substitution.
Total Synthesis of (±)-Xyloketal D and Model Studies towards the Total Synthesis of (-)-Xyloketal A
作者:Peter D. Wilson、Jeremy D. Pettigrew、Jason A. Bexrud、Rebecca P. Freeman