20767-18-4Relevant academic research and scientific papers
Synthesis method of piceatannol
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Paragraph 0021; 0025; 0026, (2016/10/10)
The present invention provides a synthesis method of piceatannol. The method comprises the following steps: reacting 3,5-dimethoxybenzyl alcohol with phosphorus oxychloride to obtain 3,5-dimethoxybenzyl chloride; adding the obtained 3,5-dimethoxybenzyl ch
Convenient One-Step Synthesis of Benzo[c]phenanthridines by Three-Component Reactions of Isochromenylium Tetrafluoroborates and Stilbenes in Acetonitrile
Chen, Gang-Gang,Wei, Jun-Qiang,Yang, Xiaoliang,Yao, Zhu-Jun
supporting information, p. 1502 - 1505 (2016/05/02)
A new type of three-component reaction of air-stable isochromenylium tetrafluoroborates with electron-rich stilbenes in acetonitrile has been developed under catalyst-free conditions in this work. This cascade multibond-formation reaction is initiated by an intermolecular oxa [4 + 2]-cycloaddition, relayed with a nucleophilic addition of acetonitrile, and terminated by an intramolecular Friedel-Crafts reaction, affording the corresponding benzo[c]phenanthridine analogues in one step.
3,5-Bis(trifluoromethyl)phenyl sulfones in the direct Julia-Kocienski olefination
Alonso, Diego A.,Fuensanta, Monica,Najera, Carmen,Varea, Montserrat
, p. 6404 - 6416 (2007/10/03)
3,5-Bis(trifluoromethyl)phenyl (BTFP) sulfones 7 have been employed in the Julia-Kocienski olefination reaction with carbonyl compounds. Sulfones 7 are readily prepared in high yields (64-97%) from commercially available 3,5-bis(trifluoromethyl)thiophenol through an alkylation/oxidation two-step sequence. The stability of metalated BTFP sulfones has been studied and compared with heteroaryl benzothiazol-2-yl (BT), 1-phenyl-1H-tetrazol-5-yl (PT), and 1-tert-butyl-1H-tetrazol-5-yl (TBT) sulfones 9-11 under different reaction conditions. The Julia-Kocienski olefination between alkyl BTFP sulfones 7 and a wide variety of aldehydes affords the corresponding 1,2-disubstituted alkenes and dienes in good yields and stereoselectivities. This one-pot protocol can be performed using KOH at room temperature or the phosphazene bases P2-Et and P4-t-Bu at -78 °C or rt and has been successfully used in a high-yielding and stereoselective synthesis of various methoxylated stilbenes such as trimethylated resveratrol. These new reaction conditions for the Julia-Kocienski olefination reaction have been also studied with BT, PT, and TBT sulfones, giving poorer results. Methylenation of aliphatic and aromatic aldehydes, ketones, and 1,2-dicarbonyl compounds is carried out through the modified Julia olefination using BTFP methyl sulfone 7d to give terminal alkenes and dienes. Mechanistic studies of the olefination reaction between benzyl BTFP sulfone 7a and aromatic aldehydes performed by KOH-induced Smiles rearrangement of stereodefined syn- and anit-β-hydroxyalkyl BTFP sulfones indicate that the stereocontrol of the reaction is determined in the elimination step. 2005 American Chemical Society.
Dihydrostilbenes of Cannabis. Synthesis of Canniprene
Crombie, Leslie,Jamieson, Sally V.
, p. 1467 - 1476 (2007/10/02)
Canniprene (10) is synthesised via reaction of a phenolate-anion ylide with a benzyl-protected aldehyde.Benzoylation, followed by hydrogenation and hydrogenolysis of the resulting stilbene, leads to a half-benzoylated bibenzyl which is converted into its O-dimethylprop-2-ynyl derivative.Semi-hydrogenation, Claisen rearrangement, and debenzoylation gives canniprene.In a second synthesis the prenylated (3-methylbut-2-enylated) and benzyl-protected ring-B section is made first and converted by Wittig reaction into a dibenzyl-protected stilbene.The stilbene is reduced and the benzyl groups removed in one step, without affecting the prenyl group, by sodium in butanol: magnesium in methanol is capable of stilbene reduction without debenzylation.This practical synthesis proceeds in 19 percent overall yield from the dimethylprop-2-ynyl ether of isovanillin (14) and is applicable to isotopelabelling.The use of p-bromophenacyl (PBP) ether and methoxyethoxymethyl (MEM) ether protection as the basis for canniprene synthesis is also considered.Other bibenzyls relevant to the natural products of Cannabis are made and the methylated chroman (37) derived from canniprene is also synthesised.
