The mechanism of cleavage under basic conditions of succinyl-anchored oligonucleotides
Studies with a model compound provide direct evidence that cleavage of succinyl-anchored oligonucleotides takes place by intramolecular nucleophilic attack of the conjugate base of the succinamide at the ester carbonyl group. An N-substituted succinamide is exclusively formed with piperidine, DBU and TBAF, but when ammonia is used this general mechanism seems to coexist with ammonolysis of the succinate ester. Cleavage with TBAF is extremely fast.
B(OCH2CF3)3-mediated direct amidation of pharmaceutically relevant building blocks in cyclopentyl methyl ether
The use of B(OCH2CF3)3 for mediating direct amidation reactions of a wide range of pharmaceutically relevant carboxylic acids and amines is described, including numerous heterocycle-containing examples. An initial screen of solvents for the direct amidation reaction suggested that cyclopentyl methyl ether, a solvent with a very good safety profile suitable for use over a wide temperature range, was an excellent replacement for the previously used solvent acetonitrile. Under these conditions amides could be prepared from 18 of the 21 carboxylic acids and 18 of the 21 amines examined. Further optimisation of one of the low yielding amidation reactions (36% yield) via a design of experiments approach enabled an 84% yield of the amide to be obtained.
Karaluka, Valerija,Lanigan, Rachel M.,Murray, Paul M.,Badland, Matthew,Sheppard, Tom D.
supporting information
p. 10888 - 10894
(2015/11/17)
Novel α-amino acid-based hydroxamic acid ligands for vanadium-catalyzed asymmetric epoxidation of allylic alcohols [2]
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Hoshino,Yamamoto
p. 10452 - 10453
(2007/10/03)
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