- Synthesis of Side Chain Substituted 3-Butylisocoumarins and Absolute Configurations of Natural Isocoumarins from Artemisia dracunculus
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A series of 3-hydroxy- and 3-bromobutyl-substituted isocoumarins was synthesized. The absolute configurations of three isocoumarin derivatives from Artemisia dracunculus, namely (-)-epoxyartemidin, (-)-2′- methoxydihydroartemidin, and (+)-3′-hydroxyartemidin were determined by chemical means via derivatization, kinetic racemate resolution (Horeau method), and comparison of the circular dichroism (CD) spectra.
- Lutz-Kutschera, Gerda,Engelmeier, Doris,Hadacek, Franz,Werner, Andreas,Greger, Harald,Hofer, Otmar
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p. 1195 - 1206
(2007/10/03)
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- A convenient one step synthesis of trans-artemidin and tetrahydrocapillarin
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trans-Artemidin 1a and tetrahydrocapillarin 1b have been synthesised by the condensation of homophthalic acid with 2-pentenoyl and pentanoyl chlorides, respectively. Alkaline hydrolysis of 1b gives the keto-acid 2b. The reduction of 2b followed by cyclode
- Shafiq, Zahid,Arfan, Muhammad,Rama, Nasim Hasan,Hussain, Mazhar,Hameed, Shahid
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p. 1523 - 1526
(2007/10/03)
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- Regioselective synthesis of natural and unnatural (Z)-3-(1- alkylidene)phthalides and 3-substituted isocoumarins starting from methyl 2- hydroxybenzoates
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(Z)-3-(1-Alkylidene)phthalides and 3-substituted isocoumarins, which include compounds bearing a substituent on their benzene ring, have been selectively and efficiently synthesized by a new protocol which involves: (i) the conversion of methyl 2-hydroxybenzoates into the corresponding nonaflates; (ii) Pd-catalyzed alkynylation reactions of these derivatives; (iii) the conversion of the so obtained methyl 2-(1-alkynyl)benzoates into the corresponding carboxylic acids followed by a transition metal-catalyzed heteroannulation reaction. This procedure has been used to prepare either natural products such as senkyunolide B, senkyunolide C, 3-propylisocoumarin and artemidin, or the MEM-ether of senkyunolide E. The regioselectivity of the transition metal-catalyzed cyclization reactions of 2-(1-alkynyl)benzoic acids has proven to be affected either by the catalyst used or the type of 1- alkynyl group present in these carboxylic acids. (C) 2000 Elsevier Science Ltd.
- Bellina, Fabio,Ciucci, Donatella,Vergamini, Piergiorgio,Rossi, Renzo
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p. 2533 - 2545
(2007/10/03)
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- Synthesis of cis- and trans-Artemidins
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Cis- and trans-artemidins (4) and (5) have been synthesised from 3-butanoylisocoumarin (1).Compound (1) on sodium borohydride reduction affords the alcohol (2) which is converted into the mesylate (3).The mesylate (3) on dehydration using 1,5-diazabicycloundecene-5 at room temperature in benzene furnishes a mixture of 4 and 5, which are separated by column chromatography over silica gel.
- Chatterjea, J. N.,Bhakta, C.,Mukherjee, Sanat K.
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p. 992 - 993
(2007/10/02)
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- New Syntheses of trans-Artemidin, Artemidinal and Tetrahydrocapillarin
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Convenient syntheses of the natural isocoumarins described in the title are reported starting from 3-bromomethylisocoumarin (2).Artemidinal (3) has been prepared in one step by subjecting 2 to Sommlet reaction. 3 on Perkin reaction using butyric anhydrid
- Chatterjea, J. N.,Mukherjee, Sanat K.,Bhakta, C.
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p. 359 - 361
(2007/10/02)
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