10335-68-9Relevant articles and documents
Studies of Collectors. IX. The Flotation of a Trace Amount of Uranium by Using 2-(Alkylamino)propionohydroxamic Acid and Cotelomer-Type Surfactants Bearing Hydroxyaminocarbonyl and Pyridyl Groups
Koide, Yoshifumi,Uchino, Masazumi,Yamada, Kimiho
, p. 3477 - 3484 (1987)
Chelating surfactants bearing hydroxyaminocarbonyl and amino groups (RnAHx) and cotelomer-type surfactants bearing hydroxyaminocarbonyl and pyridyl groups (Ls-VP-Q-Hx) were prepared and applied as flotation collectors for a trace amount of uranium.The uranium in an aqueous of pH 4-8 and in seawater was floated more effectively by ion flotation using RnAHx or by foam fractionation using Ls-VP-Q-Hx, compared with alkylhydroxamic acid (RnHx) and telomers bearing hydroxyaminocarbonyl groups (Lo-Hx).The effective floation was concluded to be due to the chelate effects between the two groups on the complex formation and to the HLB of the resulting complex.Furthermore, the uranium recoveries were examined by using a hydroxamic acid polymer (62Hx), a N-methylhydroxamic acid telomer (Ls5.6MHx), and its cotelomer (Ls3.2VP4.5MHx).
Racemization free longer N-terminal peptide hydroxamate synthesis on solid support using ethyl 2-(tert-butoxycarbonyloxyimino)-2-cyanoacetate
Manne, Srinivasa Rao,Thalluri, Kishore,Giri, Rajat Subhra,Paul, Ashim,Mandal, Bhubaneswar
, p. 6108 - 6111 (2015)
A facile, efficient, racemization-free, and environment friendly protocol for the synthesis of peptide hydroxamic acids directly from carboxylic/amino acids by ethyl 2-(tert-butoxycarbonyloxyimino)-2-cyanoacetate in the presence of DIPEA/DMAP at room temperature is described. The compatibility of this method with Fmoc based solid phase peptide synthesis (SPPS) is also demonstrated by synthesizing three relatively large N-terminal peptide hydroxamic acids on resin. Also, some biologically important hydroxamates are synthesized using this protocol.
Thioether-Directed NiH-Catalyzed Remote γ-C(sp3)-H Hydroamidation of Alkenes by 1,4,2-Dioxazol-5-ones
Chen, Qishu,Du, Bingnan,Ouyang, Yuxin,Yu, Wing-Yiu
supporting information, p. 14962 - 14968 (2021/09/29)
A NiH-catalyzed thioether-directed cyclometalation strategy is developed to enable remote methylene C-H bond amidation of unactivated alkenes. Due to the preference for five-membered nickelacycle formation, the chain-walking isomerization initiated by the NiH insertion to an alkene can be terminated at the γ-methylene site remote from the alkene moiety. By employing 2,9-dibutyl-1,10-phenanthroline as the ligand and dioxazolones as the reagent, the amidation occurs at the γ-C(sp3)-H bonds to afford the amide products in up to 90% yield (>40 examples) with remarkable regioselectivity (up to 24:1 rr).
Ethyl 2-cyano-2-(4-nitrophenylsulfonyloxyimino)acetate-mediated lossen rearrangement: Single-pot racemization-free synthesis of hydroxamic acids and ureas from carboxylic acids
Thalluri, Kishore,Manne, Srinivasa Rao,Dev, Dharm,Mandal, Bhubaneswar
, p. 3765 - 3775 (2014/05/20)
Ethyl 2-cyano-2-(4-nitrophenylsulfonyloxyimino)acetate (4-NBsOXY) mediated Lossen rearrangement and its application for the synthesis of ureas is demonstrated. Required hydroxamic acids for the Lossen rearrangements were synthesized from carboxylic acids using the same reagent. Finally, reaction of an amine with the produced isocyanate resulted in urea. Good yields without racemization were achieved under milder and simpler reaction conditions. Reactions are compatible with common N-protecting groups, such as Boc, Fmoc, Cbz, and benzyl, as well as various OH protecting groups, such as tBu and Bzl. Conversion from carboxylic acid to urea is achieved in one pot. Most importantly, byproducts Oxyma [ethyl 2-cyano-2-(hydroxyimino)acetate] and 4-nitrobenzenesulfonic acid can be recovered easily and can be recycled to prepare the reagent. Thus, the method is environmentally friendly and cost-effective.