Two-step regio- and stereoselective syntheses of [19F]- and [18F]-2-deoxy-2-(R)-fluoro-β-d-allose

Carbohydrate‐Based Molecules for Molecular Imaging in Nuclear Medicine

“…In addition to [ 18 F]FDG, other 2‐deoxysugars have also been labeled with fluorine‐18; these include 2‐deoxy‐2‐[ 18 F]fluoro‐ D ‐galactose ([ 18 F]FDGal, 21 , Figure 7),40 2‐deoxy‐2‐[ 18 F]‐β‐ D ‐allose ( 22 )41, 2‐deoxy‐2‐[ 18 F]fluoro‐ D ‐mannose,42 and 2‐deoxy‐2‐[ 18 F]fluoro‐ D ‐tallose,43 to cite a few. The 2‐deoxy‐2‐[ 18 F]fluorosugars have commonly been prepared by nucleophilic radiofluorination in similar manner to [ 18 F]FDG, from the corresponding C‐2 epimeric sugar triflates as precursors 40b,42,43.…”

“…However, unlike in the synthesis of [ 18 F]FDG, the electrophilic addition of the radiofluorine ([ 18 F]F 2 ) to the galactal produced 21 in a highly stereoselective manner 40a. 2‐Deoxy‐2‐[ 18 F]fluorosugar 22 was also obtained through anhydrous HF‐mediated electrophilic addition of [ 18 F]F 2 to the glucal 1 ; it was proposed that the epimerization at C‐3 proceeded through protonation of the oxygen bonded to C‐3, followed by 3‐ O ‐acetate cleavage assisted by attack from the acyloxy group at C‐4 and formation of a dioxolenium ion 41. Electrophilic radiofluorination was also the method of choice for the preparation of N ‐acetyl‐3‐[ 18 F]fluoroneuraminic acid ([ 18 F]Neu5Ac, 23 ), by stereoselective addition of [ 18 F]acetyl hypofluorite to the 2‐deoxy‐2,3‐dehydro‐Neu5Ac derivative 44.…”

Skin Ageing and Cancer

“…In human skin dermis, collagen-rich ECM is synthesized, organized and maintained by dermal fibroblasts [3]. Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases, which are involved in remodelling of connect tissue of many organs, including the skin [4]. More than 24 MMPs have been identified in human beings, most of which consist of multidomains [5].…”

“…More than 24 MMPs have been identified in human beings, most of which consist of multidomains [5]. MMPs activity is regulated at multiple levels: gene expression, zymogens activation and inhibition by specific inhibitors [4]. In skin, MMPs are produced by several different types of cells such as fibroblasts, keratinocytes, macrophages, endothelial cells, mast cells and eosinophils [6].…”

General Approach to Five-Membered Nitrogen Heteroaryl C-Glycosides Using a Palladium/Copper Cocatalyzed C–H Functionalization Strategy

“…If the reaction proceeded as we anticipated, it would have several advantages that would include (1) high generality, (2) high reaction efficiency because it would use C–H activation, and (3) diversified subsequent modifications by it allowing conversion of the double bond into other functional groups such as 2-deoxysugars by hydrogenation . It would also allow the ready introduction of hydroxyl, nitrogen, or halogen groups and expand the diversity of 2-heteroaryl- C -glycosides that could be prepared for the screening of bioactive compounds. Based on this design, we report our results on the synthesis of various 2-heteroaryl- C -Δ 1,2 -glycosides by the Pd/Cu cocatalyzed C–H functionalization of heterocycles with 1-iodoglycals.…”