- A new photolabile linker for the photoactivation of carboxyl groups
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A new photolabile linker enabling nucleophilic cleavage of a carboxyl functionality upon irradiation with UV light (>290 nm) was developed. When the photocleavage is carried out in the presence of primary or secondary amines, amides are obtained in high yields and purifies, while the intramolecular version of this reaction leads to heterocycles via a cyclorelease mechanism.
- Nicolaou,Safina,Winssinger
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- Divergent synthesis of α-functionalized amides through selective N-O/C-C or N-O/C-C/C-N cleavage of aza-cyclobutanone oxime esters
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Herein, a novel sequential ring opening reaction of aza-cyclobutanone oxime esters with isocyanides is described. The reaction proceeded smoothly under redox-neutral and mild conditions, leading to a divergent synthesis of α-cyanomethylaminoamides, α-acyloxyamides and α-acylaminoamides. In these transformations, a selective N-O/C-C or N-O/C-C/C-N cleavage was achieved only by changing the iron-catalyst system. Among them, a rare sequential N-O/C-C/C-N cleavage process with a classical Passerini or Ugi multicomponent reaction can be executed in a single step. To the best of our knowledge, this work creates a novel reaction mode of cycloketone oximes and provides new opportunities for reaction design.
- Cai, Zhong-Jian,Ji, Shun-Jun,Jiang, Nan-Quan,Li, Hai-Yan,Liu, Hua-Wei,Wang, Dian-Liang
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supporting information
p. 9618 - 9621
(2021/09/28)
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- Glycolamide esters as biolabile prodrugs of carboxylic acid agents: synthesis, stability, bioconversion, and physicochemical properties.
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Benzoic acid esters of various substituted 2-hydroxyacetamides (glycolamides) were found to be hydrolyzed extremely rapidly in human plasma solutions, the half-lives of hydrolysis being less than 5 s in 50% plasma solutions for some N,N-disubstituted glycolamide esters. The rapid rate of hydrolysis could be largely attributed to cholinesterase (also called pseudocholinesterase) present in plasma. From a study of a variety of substituted glycolamide esters and structurally related esters, the most prominent structural requirement needed for a rapid rate of hydrolysis was found to be the glycolamide ester structure combined with the presence of two substituents on the amide nitrogen atom. A structural similarity of such esters with benzoylcholine, a good substrate for cholinesterase, was put forward. Esters of N,N-disubstituted glycolamides are suggested to be a useful biolabile prodrug type for several carboxylic acid agents. The esters combine a high susceptibility to undergo enzymatic hydrolysis in plasma with a high stability in aqueous solution. Furthermore, as demonstrated with the benzoic acid model esters, it is feasible to obtain ester derivatives with almost any desired water solubility or lipophilicity with retainment of marked lability to enzymatic hydrolysis.
- Nielsen,Bundgaard
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p. 285 - 298
(2007/10/02)
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