Biomimetic Synthesis and Properties of Polyprenoid

Abstract

This chapter is dedicated to the memory of Marie-Claire Dillenseger and Pr Guy Ourisson.

Sterols and Stanols Preserved in Pond Sediments Track Seabird Biovectors in a High Arctic Environment

“…A few of the sterols and stanols are already known to have associations with specific sources. Cholesterol is an essential component in cell membranes, and thus it is one of the most commonly found sterols in all organisms, especially animals (Kingdom Animalia). , It has long been used as an indicator for marine animal material in aquatic environments. − However, sitosterol is a common sterol in plant tissue and wax, , and it is widely reported in phytogenic material, ,, including algae. , Coprostanol is widely used to trace municipal sewage input in aquatic environments. , However, it is also reported in bird guano at a lower concentration. ,, Meanwhile, epicoprostanol in Arctic environments should be strongly related to human activities due to its distinctive presence in human sewage, , although it is also found in livestock and poultry waste, which are not expected in the Arctic …”

“…43−46 However, sitosterol is a common sterol in plant tissue and wax, 47,48 and it is widely reported in phytogenic material, 40,49,50 including algae. 51,52 Coprostanol is widely used to trace municipal sewage input in aquatic environments. 53,54 However, it is also reported in bird guano at a lower concentration.…”

BF3·OEt2 mediated metal-free one-pot sequential multiple annulation cascade (SMAC) synthesis of complex and diverse tetrahydroisoquinoline fused hybrid molecules

“…Although few approaches have been reported, there is still a need to develop a straightforward synthesis of THIQs from readily available starting materials. It is a well-known fact that nature uses the strategy of multiple annulations through cascade reactions, 16 and this is the basis for the origin of new synthetic challenges aiming at novel and simple access to structurally distinct, complex and hybrid scaffolds through cascade reaction sequences, such as build-couple-pair strategies, folding pathways, branching pathways and structural variations in the scaffold building agent. 17 The cascade or domino reaction sequences play a crucial role in multiple bond forming transformations (MBFTs) 18 and the building up of molecular complexity.…”