Metal-catalysed C–H bond functionalisation has had a significant impact on how chemists make molecules. Translating the methodological developments to their use in the assembly of complex natural products is an important challenge for the continued advancement of chemical synthesis. In this tutorial review, we describe selected recent examples of how the metal-catalysed C–H bond functionalisation has been able to positively affect the synthesis of natural products.

Recent developments in natural product synthesis using metal-catalysed C–H bond functionalisation

Occurrence, Biogenesis, and Synthesis of Biologically Active Carbazole Alkaloids

https://chemistry.mdma.ch/hiveboard/rhodium/pdf/piper.phytochemistry.pdf

Phytochemistry of the genus Piper

Tubulin is the biochemical target for several clinically used anticancer drugs, including paclitaxel and the vinca alkaloids vincristine and vinblastine. This review describes both the natural and synthetic agents which are known to interact with tubulin. Syntheses of the more complex agents are referenced and the potential clinical use of the compounds is discussed. This review describes the biochemistry of tubulin, microtubules, and the mitotic spindle. The agents are discussed in relation to the type of binding site on the protein with which they interact. These are the colchicine, vinca alkaloid, rhizoxin/maytansine, and tubulin sulfhydryl binding sites. Also included are the agents which either bind at other sites or unknown sites on tubulin. The literature is reviewed up to October 1997. © 1998 John Wiley & Sons, Inc., Med Res Rev, 18, No. 4, 259–296, 1998.

Tubulin as a target for anticancer drugs: agents which interact with the mitotic spindle.

The recent advent of transition-metal mediated CH activation is revolutionizing the synthetic field and gradually infusing a “CH activation mind-set” in both students and practitioners of organic synthesis. As a powerful testament of this emerging synthetic tool, applications of CH activation in the context of total synthesis of complex natural products are beginning to blossom. Herein, recently completed total syntheses showcasing creative and ingenious incorporation of CH activation as a strategic manoeuver are compared with their “non-CH activation” counterparts, illuminating a new paradigm in strategic synthetic design.

C-H activation: a complementary tool in the total synthesis of complex natural products.

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.

https://journals.sagepub.com/doi/pdf/10.1177/1934578X0700200709

N-(4-Methylphenyl) benzenepropanamide - the First Isolated Amide from the Genus Paederia

N-Methyl-C-arylnitrones have been synthesized in very high yields within a few minutes from N-methyl-hydroxylamine hydrochloride and aryl aldehydes in presence of sodium hydrogen carbonate in methylene chloride using the microwave irradiation technique.

1,3-Dipolar Cycloadditions. Part 8. Microwave Irradiation Assisted Synthesis of N-Methyl-C-aryl Nitrones.

1,3-Dipolar Cycloadditions. Part 6. Structure and Conformation of Cycloadducts from Reactions of C-Aryl-N-phenylnitrones with Substituted Cinnamic Acid Amides.

Ab s t r Ac t Introduction: Shigru or Moringa oleifera Lam. (Moringaceae) is a very useful medicinal plant in folklore medicines of Africa and Asia for the treatment of diseases like ulcers, wounds, inflammation, heart problem, stroke, obesity, anemia, and liver damage. Moreover, the plant leaves are very good supplements for malnutrition and are also used as an antimicrobial agent. The present work was carried out for assessment of physicochemical constants screening of phytochemicals and high performance thin layer chromatography (HPTLC) fingerprinting of the plant samples. Materials and methods: The crude powders of M. oleifera leaves of two varieties, collected from India and Tanzania, were subjected to the physicochemical analysis. The methanolic extracts of the respective leaves were subjected to phytochemical screening to determine the classes of phytoconstituents present and generate HPTLC fingerprinting profiles. Results: Phytochemical screening showed the presence of tannins, flavonoids, terpenoids, alkaloids, saponins, carbohydrates, reducing sugars, and proteins in both the varieties, but in different concentrations. The HPTLC finger printing profile of the methanolic extract of the M. oleifera leaves collected from Tanzania showed more number of bands with higher concentrations as compared to that of the Indian variety. Conclusion: This research article compares the physicochemical and phytochemical parameters as well as HPTLC profiles of the leaves of the two designated M. oleifera varieties. Besides the importance for authenticating the plant samples, the present results also show that both the varieties can be used as herbal drugs for different purposes.

Phytochemical Screening and High Performance Thin Layer Chromatography Fingerprinting Profiles of Shigru (Moringa oleifera Lam.) Leaves from Tanzania and India

A study was conducted in four major soils of Kerala namely red loam (Vellayani series), laterite (Trivandrum series), coastal sandy (Kazhakuttam series) and forest soil (Kallar series) to assess the impact of different agricultural land use systems on soil carbon dynamics. Surface soil samples (0-15 cm depth) were collected and analyzed for soil properties and carbon pools following standard procedures and carbon stock in soil was also calculated. The results indicated that various land use categories had a significant effect on soil properties and carbon pools. The soil organic carbon values ranged from 2.96 to 9.93 g kg-1. The highest value was recorded under rubber land use in Kallar soil, which is significantly higher (about 3.6 times) than the coconut land use in Kazhakuttam soil which had the least value. The highest carbon stock of 23.02 kg m-2 was recorded in rubber land use in Kallar soil. The total particulate organic carbon concentration was also found to be the highest in rubber land use (Kallar series). The highest concentrations of labile carbon were found in soils from coconut plantation site (2516 mg kg-1), followed by rice field (2187 mg kg-1), whereas the lowest concentration was detected in homestead site (940 mg kg-1). Hot water soluble carbon in soil ranged between 18.14 and 76.45 mg kg-1 Cumulative amount of carbon mineralized in 15 days of incubation ranged from 2.86 to 6.39 mg C kg-1 soil.

https://www.phytojournal.com/archives/2019/vol8issue2S/PartA/Sp-8-2-5-260.pdf

Avijit Banerji

Papers

N-(4-Methylphenyl) benzenepropanamide - the First Isolated Amide from the Genus Paederia

1,3-Dipolar Cycloadditions. Part 8. Microwave Irradiation Assisted Synthesis of N-Methyl-C-aryl Nitrones.

1,3-Dipolar Cycloadditions. Part 6. Structure and Conformation of Cycloadducts from Reactions of C-Aryl-N-phenylnitrones with Substituted Cinnamic Acid Amides.

Phytochemical Screening and High Performance Thin Layer Chromatography Fingerprinting Profiles of Shigru (Moringa oleifera Lam.) Leaves from Tanzania and India

Phytochemical analysis and HPTLC finger-printing profile of roots of Alstonia scholaris (L.) R.Br (Saptaparṇa)