- The taming of capsaicin. Reversal of the vanilloid activity of N-acylvanillamines by aromatic iodination
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Aromatic iodination ortho to the phenolic hydroxyl reverts the activity of the ultrapotent vanilloid agonist resiniferatoxin (RTX, 1a), generating the ultrapotent antagonist 5′-iodoRTX (1b). To better understand the role of iodine in this remarkable switch of activity, a systematic investigation on the halogenation of vanillamides, a class of compounds structurally simpler than resiniferonoids, was carried out. The results showed that (a) the antagonistic activity depends on the site of halogenation and is maximal at C-6′, (b) iodine is more efficient than chlorine and bromine at reverting the agonistic activity, and (c) iodine-carbon exchange decreases antagonist activity. Iodine-induced reversal of vanilloid activity was also observed in vanillamides more powerful than capsaicin, but a poor correlation was found between agonistic and antagonistic potencies, suggesting that differences exist in the way vanillamides and their 6′-iodo derivatives bind to TRPV1.″
- Appendino, Giovanni,Daddario, Nives,Minassi, Alberto,Moriello, Aniello Schiano,De Petrocellis, Luciano,Di Marzo, Vincenzo
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- A Modular Access to (±)-Tubocurine and (±)-Curine - Formal Total Synthesis of Tubocurarine
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Two consecutive Cu-catalyzed Ullmann-type C-O couplings permitted the first successful entry toward the curare alkaloids (±)-tubocurine and (±)-curine. Starting from vanillin, the synthetic sequence comprises 15 linear steps and includes a total of 24 transformations. In addition, the total synthesis of tubocurine represents a formal total synthesis of the famous arrow poison alkaloid tubocurarine.
- Otto, Nicola,Ferenc, Dorota,Opatz, Till
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p. 1205 - 1217
(2018/06/18)
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