First total synthesis of tenuifolin via PIFA mediated oxidative biaryl coupling
The first total synthesis of a sesquiterpenoid, tenuifolin, was achieved in seven linear steps. Phenyliodine(III) bis(trifluoacetate) (PIFA) mediated oxidative biaryl coupling was employed as a key step to construct the central seven-membered ring with a double bond. The double bond formation was also exploited.
A New Synthesis of some naturally occuring Isocoumarins. 8-Hydroxy-3-methyl-3,4-dihydroisocoumarin (Mellein) and 8-Hydroxy-3-methylisocoumarin
3-Methyl-8-methoxyisochroman (5a) on oxidation furnishes 3-methyl-8-methoxy-3,4-dihydroisocoumarin (6a), and demethylated with hydriodic acid to 3-methyl-8-hydroxy-3,4-dihydroisocoumarin (mellein) (7a).Treatment of 6a with N-bromosuccinimide followed by refluxing with triethylamine furnishes 3-methyl-8-methoxyisocoumarin (8a) which on demethylation with hydriodic acid yields 3-methyl-8-hydroxyisocoumarin (9a). 5a and 3-methyl-6-methoxyisochroman (5b) obtained by treating 3-(m-methoxyphenyl)propan-2-ol (4) with HCHO/HCl are separated by fractional distillation. 4 is obtained from m-methoxyphenylacetaldehyde (3) by Grignard reaction with methylmagnesium bromide.The aldehyde (3) is obtained from m-methoxybenzaldehyde (1) by Darzens glycidic ester condensation followed by hydrolysis and decarboxylation of the resulting product.
Sinha, Jawahar,Singh, Ramyan Prasad,Srivastava, Jagdish N.
p. 907 - 909
(2007/10/02)
Antiviral potentials. XII. Glycidic esters
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Ulian,Vio
p. 518 - 521
(2007/10/08)
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