Novel design and synthesis of a radioiodinated glycolipid analog as an acceptor substrate for N ‐acetylglucosaminyltransferase V

Guided by the known molecular recognition interactions between N ‐acetylglucosaminyltransferase V (GnT‐V) and certain synthetic substrates, we synthesized a radiolabeled double‐stranded glycolipid composed of a long‐chain alkyl unit and a radioiodinated phenylalkyl unit, [ 125 I]‐2‐[ N ‐(2‐hydroxy‐3‐hexadecyloxy)propyl‐15‐(4‐iodophenyl)pentadecanecarboxamido]ethyl 2‐acetamido‐2‐deoxy‐β‐ d ‐glucopyranosyl‐(1→2)‐α‐ d ‐mannopyranosyl‐(1→6)‐β‐ d ‐glucopyranoside ([ 125 I]2), as a novel intravital glycolipid mimic substrate of GnT‐V. The radioactive iodine ( 125 I) was incorporated via iododestannylation of the phenyltributyltin derivative, 2‐[ N ‐(2‐acetoxy‐3‐hexadecyloxy)propyl‐15‐(4‐tributylstannylphenyl)pentadecanecarboxamido]ethyl 3,4,6‐tri‐ O ‐acetyl‐2‐acetamido‐2‐deoxy‐β‐ d ‐glucopyranosyl‐(1→2)‐3,4,6‐ O ‐acetyl‐α‐ d ‐mannopyranosyl‐(1→6)‐2,3,4‐tri‐ O ‐acetyl‐β‐ d ‐glucopyranoside (26). Subsequent deacetylation at the final step afforded [ 125 I]2.