Synthesis of isoquinoline and yohimbinoid alkaloids

A systematic survey of the different synthetic methodologies available for the syntheses of isoquinoline and yohimbinoid alkaloids revealed that the general approaches to these compounds involved either an A/B → C → D/ → E approach or a D/E → C/B/A approach% We have now devised a novel method for the syntheses of both the isoquinoline and indole alkaloids belonging to the tetra-hydroprotoberberine and yohimbinoid skeleton. In the method developed by us a suitable 'D' ring is first chosen on which the 'C' ring is built. This bicyclic C/D ring system is then cleaved by condensing with a suitable A/B unit bearing an amine so that an overall A/B → seco C/D ring system is generated. By appropriate reactions the total synthesis of the alkaloids has been achieved in which the seco 'C' ring undergoes cyclisation. The total syntheses of two tetrahydroprotoherberine alkaloids, (±) 2,3-dimethoxyberbine and (+)-norcoralydine and three pentacyclic indole compounds, (±) decarbcethoxy dihydrogambirtannine, (±)alloyohimbine aid (±)rauwolscine will be discussed. Our method for the synthesis of these alkaloids was based on the choice of 3-isochromanone derivative as a suitable synthon for the construction of the nonnitrogenous moiety. The nitrogenous portion was derived from tryptamine. Since 3-isochromanones belong to σ-lactcnes they can readily be prepared from 2-indanones by Bayer-Villiger oxidation. However, the conventional method for the synthesis of 2-indanone is not a simple procedure. An improved method for 2-indenone and its derivatives has been developed by us using a diazoketone intermediate. A unique acid catalysed diazoketone cyclisation procedure yielded the desired 2-indanones in good yields

An Overview of the Genus Nardostachys

Nardostachys jatamansi, a medicinally important herb of Nepalese origin, has been used for centuries in the Ayurvedic and Unani systems of medicine. In combination with Marsilea minuta it is being used as an antistress and anticonvulsant drug and also finds use in the treatment of epilepsy. Recently, it has been reported that N. jatamansi, which plays an important role in protecting from cerebral ischemia and liver damage, is also used for the treatment of osteoporosis and hypercalcemia. The other member of the genus Nardostachys, N. chinensis, possesses antifungal and antimalarial properties. It is also used in the treatment of skin dysfunction. A short summary of the chemical constituents of the two species along with their physical and biological properties is reported

New synthesis of (+) 2,3-dimethoxyhexahydroberbine

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N-(4-Methylphenyl) Benzenepropanamide - the First Isolated Amide From the Genus Paederia

Investigation of the stem of Paederia foetida (Rubiaceae) resulted in the isolation and characterization of N-(4-methylphenyl)-benzopropanamide, which was hitherto unknown as a natural product This is the first report of an amide for the genus Paederia

Revised structure of the condensation product of N-(p-methoxyphenyl)anthranilic acid with formamide

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Use of periodic acid for detecting and locating ethylenic unsaturation

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Alkaloids of the roots of Rauwolfia densiflora BENTH. and HOOK, Rauwolfia perakensis KING and GAMBLE, Rauwolfia canescens LINN. and Rauwolfia serpentina BENTH

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Constitution and synthesis of glycosin, the new alkaloid of Glycosmis Pentaphylla, Retz. DC.

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On the constitution of the active principles isolated from the matured bark of Aegle marmelos, Correa

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