29053-23-4Relevant articles and documents
Cascade reactions of nitrogen-substituted isocyanates: A new tool in heterocyclic chemistry
Vincent-Rocan, Jean-Fran?ois,Ivanovich, Ryan A.,Clavette, Christian,Leckett, Kyle,Bejjani, Julien,Beauchemin, André M.
, p. 315 - 328 (2015/12/26)
In contrast to normal C-substituted isocyanates, nitrogen-substituted isocyanates (N-isocyanates) are rare. Their high reactivity and amphoteric/ambident nature has prevented the scientific community from exploiting their synthetic potential. Recently, we have developed an in situ formation approach using a reversible equilibrium, which allows controlled generation and reactivity of N-isocyanates and prevents the dimerization that is typically observed with these intermediates. This blocked (masked) N-isocyanate approach enables the use of various N-isocyanate precursors to assemble heterocycles possessing the N-N-CO motif, which is often found in agrochemicals and pharmaceuticals. Cascade reactions for the rapid assembly of several valuable 5- and 6-membered heterocycles are reported, including amino-hydantoins, acyl-pyrazoles, acyl-phthalazinones and azauracils. Over 100 different compounds were synthesized using amino-, imino- and amido-substituted N-isocyanates, demonstrating their potential as powerful intermediates in heterocyclic synthesis. Their reactivity also enables access to unprecedented bicyclic derivatives and to substitution patterns of azauracils that are difficult to access using known methods, illustrating that controlled reactivity of N-isocyanates provides new disconnections, and a new tool to assemble complex N-N-CO containing motifs.
Semicarbazone-based inhibitors of cathepsin K, are they prodrugs for aldehyde inhibitors?
Adkison, Kim K.,Barrett, David G.,Deaton, David N.,Gampe, Robert T.,Hassell, Anne M.,Long, Stacey T.,McFadyen, Robert B.,Miller, Aaron B.,Miller, Larry R.,Payne, J. Alan,Shewchuk, Lisa M.,Wells-Knecht, Kevin J.,Willard Jr., Derril H.,Wright, Lois L.
, p. 978 - 983 (2007/10/03)
Starting from potent aldehyde inhibitors with poor drug properties, derivatization to semicarbazones led to the identification of a series of semicarbazone-based cathepsin K inhibitors with greater solubility and better pharmacokinetic profiles than their parent aldehydes. Furthermore, a representative semicarbazone inhibitor attenuated bone resorption in an ex vivo rat calvarial bone resorption model. However, based on enzyme inhibition comparisons at neutral pH, semicarbazone hydrolysis rates, and 13C NMR experiments, these semicarbazones probably function as prodrugs of aldehydes.
