130459-53-9Relevant academic research and scientific papers
A General Catalytic Method for Highly Cost- and Atom-Efficient Nucleophilic Substitutions
Huy, Peter H.,Filbrich, Isabel
supporting information, p. 7410 - 7416 (2018/04/30)
A general formamide-catalyzed protocol for the efficient transformation of alcohols into alkyl chlorides, which is promoted by substoichiometric amounts (down to 34 mol %) of inexpensive trichlorotriazine (TCT), is introduced. This is the first example of a TCT-mediated dihydroxychlorination of an OH-containing substrate (e.g., alcohols and carboxylic acids) in which all three chlorine atoms of TCT are transferred to the starting material. The consequently enhanced atom economy facilitates a significantly improved waste balance (E-factors down to 4), cost efficiency, and scalability (>50 g). Furthermore, the current procedure is distinguished by high levels of functional-group compatibility and stereoselectivity, as only weakly acidic cyanuric acid is released as exclusive byproduct. Finally, a one-pot protocol for the preparation of amines, azides, ethers, and sulfides enabled the synthesis of the drug rivastigmine with twofold SN2 inversion, which demonstrates the high practical value of the presented method.
ZnO nanorods as an efficient and heterogeneous catalyst for N-Boc protection of amines and amine derivatives
Nouria, Azita,Akbari, Jafar,Heydaric, Akbar,Nouri, Arezu
experimental part, p. 38 - 42 (2012/05/04)
An efficient ZnO nano catalyst, which was readily prepared from Zn(CH3CO2)2, 2H2O and PVP by a chemical solution approach has successfully catalyzed N-tertbutoxy carbonylation of amines. The ZnO nanorods were successful and gave promising results for highly active and chemoselective as well as easily recyclable catalyst for the NBoc protection reaction of a wide variety of amines. The catalyst could be easily recycled for five times without noticeable decrease in catalytic activity. The ZnO nanocatalyst was characterized with XRD and SEM.
Thioglycoluril as a highly efficient, recyclable and novel organocatalyst for N-Boc protection of amines
Khaksar, Samad,Vahdat, Seyed Mohammad,Tajbakhsh, Mahmood,Jahani, Fatemeh,Heydari, Akbar
experimental part, p. 6388 - 6391 (2011/01/03)
A simple and efficient protocol for the chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butyl dicarbonate using thioglycoluril as the catalyst is described. The catalyst can be readily separated from the reaction products by simple filtration and recovered for reuse. No competitive side reactions, such as formation of isocyanate, urea, oxazolidinone, and N,N-di-Boc derivatives were observed.
Protic ionic liquid [TMG][Ac] as an efficient, homogeneous and recyclable catalyst for Boc protection of amines
Akbari, Jafar,Heydari, Akbar,Ma'mani, Leila,Hassan Hosseini, Seyed
experimental part, p. 544 - 547 (2010/11/05)
An efficient and practical protocol for the chemoselective N-Boc protection of various structurally different aryl, aliphatic and heterocyclic amines was carried out with (Boc)2O using protic 1, 1, 3, 3-tetra-methylguanidinium acetate (10 mol%) as recyclable catalyst under solvent free condition at ambient temperature. No competitive side reactions (isocyanate, urea and N, N-di-Boc) were observed. α-Amino alcohols afforded the N-Boc-derivative without oxazolidinone formation.
Experimental and DEE study of the conversion of ephedrine derivatives into oxazolidinones. Double SN2 mechanism against SN1 mechanism
El Moncef, Abdelkarim,El Hadrami, El Mestafa,González, Miguel A.,Zaballos, Elena,Zaragozá, Ramón J.
body text, p. 5173 - 5184 (2010/08/22)
Sulfonation of the N-Boc derivatives of 1,2-aminoalcohols, such as ephedrine, pseudoephedrine, norephedrine, norpseudoephedrine, thiomicamine, and chloramphenicol yields a mixture of the corresponding oxazolidinones with inversion (erythro derivatives) and!or retention of configuration (threo derivatives)at C5. We suggest a competition between two mechanisms: an intramolecular SN2 process initiated by attack of the carbonyl oxygen of the Boc group to the benzylic carbon and the other one through a double SN2 process. In the erythro derivatives the first mechanism is predominant, while in the threo derivatives both mechanisms have similar energy. This hypothesis is supported by theoretical calculations and additional experimental assays.
Hydrogen bond catalyzed chemoselective N-tert-butoxycarbonylation of amines
Khaksar, Samad,Heydari, Akbar,Tajbakhsh, Mahmood,Vahdat, Seyed Mohammad
, p. 3527 - 3529 (2008/09/21)
A novel, chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butoxypyrocarbonate (Boc)2O is described that relies on selective carbonyl activation by hydrogen bond formation. This mild, acid- and metal-free process requires only catalytic amounts of thiourea as hydrogen bond donor.
1,1,1,3,3,3-Hexafluoroisopropanol: A recyclable organocatalyst for N-Boc protection of amines
Heydari, Akbar,Khaksar, Samad,Tajbakhsh, Mahmood
experimental part, p. 3126 - 3130 (2009/04/06)
A simple and efficient protocol for the chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butyl dicarbonate using 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as solvent and catalyst is described. The catalyst can be readily separated from the reaction products and recovered for direct reuse. No competitive side reactions such as formation of isocyanate, urea, and N,N-di-Boc were observed. α-Amino alcohols afforded the N-Boc derivatives without oxazolidinone formation. Georg Thieme Verlag Stuttgart.
N-tert-Butoxycarbonylation of amines using H3PW12O40 as an efficient heterogeneous and recyclable catalyst
Heydari, Akbar,Shiroodi, Roohollah Kazem,Hamadi, Hossein,Esfandyari, Maryam,Pourayoubi, Mehrdad
, p. 5865 - 5868 (2008/02/09)
The commercially available heteropoly acid H3PW12O40 (0.5 mol %) is a very efficient and environmentally benign catalyst for N-tert-butoxycarbonylation of amines (primary, secondary) with di-tert-butyl dicarbonate at room temperature in short reaction times (10 min). No competitive side products such as isocyanates, ureas, N,N-di-tert-butoxycarbonyls, O-Boc and oxazolidinones were observed. Chiral α-amino alcohols and esters afforded the corresponding N-Boc derivatives chemoselectively in excellent yields.
Efficient and selective Al-catalyzed alcohol oxidation via oppenauer chemistry
Graves, Christopher R.,Zeng, Bi-Shun,Nguyen, SonBinh T.
, p. 12596 - 12597 (2008/02/03)
A highly active and selective Al-based catalytic Oppenauer (O) oxidation is reported. Quantitative and selective oxidations of a variety of benzylic, propargylic, allylic, and aliphatic primary and secondary alcohols were achieved using nitrobenzaldehyde derivatives as the oxidant and simple aluminum compounds as precatalysts. Copyright
Lithium perchlorate-catalyzed Boc protection of amines and amine derivatives
Heydari, Akbar,Hosseini, Seyed Esmaeil
, p. 1929 - 1932 (2007/10/03)
A new mild and chemoselective method for mono-N-protection of amines and amine derivatives as tert-butoxycarbonyl derivatives is reported. The reaction proceeds with lithium perchlorate (20 mol %) and pyrocarbonates, and shows general applicability. The catalytic action of LiClO4 is specific for the activation of Boc2O, thus acid-sensitive functionalities of the starting materials remain unchanged in the protection process. This procedure works well for sterically hindered primary amine as well as electron-deficient primary arylamines, primary and secondary amino alcohols, α-amino acid esters, hydroxylamines, hydrazines and sulfonamides.
