In homogeneous catalysis, the catalyst is in the same phase as the reactant. The number of collisions between reactants and catalyst is at a maximum.In a patent, 119139-23-0, name is 3,4-Di(1H-indol-3-yl)-1H-pyrrole-2,5-dione, introducing its new discovery. Formula: C20H13N3O2
Total synthesis of cryptophycin-24 (arenastatin A) amenable to structural modifications in the C16 side chain
Two efficient protocols for the synthesis of tert-butyl (5S,6R,2E,7E)-5-[(tert-butyldimethylsilyl)-oxy]-6-methyl-8-phenyl-2,7-octadie noate, a major component of the cryptophycins, are reported. The first utilized the Noyori reduction and Frater alkylation of methyl 5-benzyloxy-3-oxopentanoate to set two stereogenic centers, which became the C16 hydroxyl and C1′ methyl of the cryptophycins. The second approach started from 3-p-methoxybenzyloxypropanal and a crotyl borane reagent derived from (-)-alpha-pinene to set both stereocenters in a single step and provided the dephenyl analogue, tert-butyl (5S,6R,2E)-5-[(tert-butyldimethylsilyl)oxy]-6-methyl-2,7-octadienoate, in five steps. This compound was readily converted to the 8-phenyl compound via Heck coupling. The silanyloxy esters were efficiently deprotected and coupled to the C2-C10 amino acid fragment to provide desepoxyarenastatin A and its dephenyl analogue. The terminal olefin of the latter was further elaborated via Heck coupling. Epoxidation provided cryptophycin-24 (arenastatin A).
We¡¯ll also look at important developments in the pharmaceutical industry because understanding organic chemistry is important in understanding health, medicine, the role of 119139-23-0, and how the biochemistry of the body works.Formula: C20H13N3O2
Reference£º
Chiral nitrogen ligands in late transition metal-catalysed asymmetric synthesis¡ªI. Addressing the problem of ligand lability in rhodium-catalysed hydrosilations,
Nitrogen-Containing Ligands for Asymmetric Homogeneous and Heterogeneous Catalysis