409314-87-0Relevant academic research and scientific papers
Copper catalyzed oxidative coupling of amines with formamides: A new approach for the synthesis of unsymmetrical urea derivatives
Kumar, G. Sathish,Kumar, R. Arun,Kumar, P. Santhosh,Reddy, N. Veera,Kumar, K. Vijaya,Kantam, M. Lakshmi,Prabhakar,Reddy, K. Rajender
supporting information, p. 6686 - 6688 (2013/07/26)
Direct access to unsymmetrical urea derivatives via copper catalysed C-H/N-H coupling of formamides with amines has been developed at room temperature. This protocol is also applied to the synthesis of chiral urea derivatives.
PROTON ACCEPTOR IMINIUM/CARBOCATION-TYPE COUPLING AGENTS
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, (2010/06/19)
Novel iminium-type coupling agents containing proton acceptors in their iminium moiety, which can be used beneficially as coupling agents in various chemical polypeptide and/or polynucleotide syntheses, and are particularly useful as yield enhancing and racemization suppressing coupling agents for use in peptide syntheses, are disclosed. Further disclosed are a process of preparing such iminium-type coupling agents and their use in the preparation of polypeptides and/or polynucleotides.
A novel family of onium salts based upon isonitroso meldrum's acid proves useful as peptide coupling reagents
El-Faham, Ayman,Subiros-Funosas, Ramon,Albericio, Fernando
experimental part, p. 3641 - 3649 (2010/09/03)
A new family of uronium salts (HTMU, HMMU, and HDmPyMU) based on isonitroso Meldrum's acid (HONM) are reported as stand-alone coupling reagents. Amide bond formation with the use of these reagents occurred more quickly than that with other uronium salts as a result of the presence of a neighboring group effect with a cyclic structure. Thus, these novel onium salts were often more effective in the acylation of poor nucleophiles and in the control of optical purity than related Oxyma- and benzotriazole-based reagents. Among the HONM derivatives, HMMU showed the best performance in reducing racemization and assembling demanding sequences such as the Aib-ACP decapeptide or analogues of Leu-enkephalin pentapeptide, Furthermore, the scope and limitations of the use of HONM as an additive in combination with carbodiimides is discussed.
COMU: A safer and more effective replacement for benzotriazole-based uronium coupling reagents
El-Faham, Ayman,Funosas, Ramon Subiros,Prohens, Rafel,Albericio, Fernando
scheme or table, p. 9404 - 9416 (2010/04/03)
We describe a new family of uronium-type coupling reagents that differ in their iminium moieties and leaving groups. The presence of the morpholino group in conjunction with an oxime derivative-especially ethyl 2-cy ano-2- (hydroxyimino) acet ate (Oxyma)-had a marked influence on the solubilities, stabilities, and reactivities of the reagents. Finally, the new uronium salt derived from Oxyma (COMU) performed extremely well in the presence of only 1 equiv of base, thereby confirming the effect of the hydrogen bond acceptor in the reaction. COMU also showed a less hazardous safety profile than the benzotriazolebased HDMA and HDMB, which exhibited unpredictable autocatalytic decompositions. Furthermore, the Oxyma moiety contained in COMU suggests a lower risk of explosion than in the case of the benzotriazole derivatives.
Design and synthesis of new immonium-type coupling reagents
El-Faham, Ayman,Khattab, Sherine N.,Abdul-Ghani, Mohamed,Albericio, Fernando
, p. 1563 - 1573 (2007/10/03)
A new family of immonium-type coupling reagents is de-scribed here. The differences in the carbocation skeletons of these reagents can be correlated with differences in stability and thus reactivity. The dihydroimidazole derivatives are highly unstable to air, whereas the salts derived from dimethylamine are the most stable and the pyrrolidino derivatives are of intermediate stability. These results should be taken into account mainly when coupling reagents are deposited in open vessels, such in some automatic synthesizers. As regards both coupling yield and retention of configuration, HOAt derivatives have been confirmed to be superior to those of HOBt in all cases. For peptides containing hindered residues, fluoroformamidinium salts are more convenient than the HOAt-based reagents. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Chloroformamidinium salts: Efficient reagents for preparation of 2-aminobenzoimidazole, 2-aminobenzoxazole, and 2-aminobenzothiazole derivatives
El-Faham, Ayman,Chebbo, Mohamed,Abdul-Ghani, Mohamed,Younes, Ghassan
, p. 599 - 606 (2007/10/03)
A Reaction involving chloroformamidinium salts (TCFH 1a, BTCFH 1b, DmCFH 1c, DmPCFH 1d, BPCFH 1e) and 2-aminophenol 9a, benzene-1,2-diamine 9b, and 2-aminothiophenol 9c afforded 2-aminobenzoxazole 13, 2-aminobenzoimidazole 14, and 2-aminobenzothiazole 15 derivatives, respectively as major products, due to the in situ heterocyclization with dimethylamine acting as the better leaving group. Attempts for preparation of 13-15 from the reaction of N,N-dimethyl carbomyl chloride 16 with 2-aminophenol 9a, benzene-1,2-diamine 9b, and 2-aminothiophenol 9c were unsuccessful, and gave the unexpected products benzoxazol-2-ol 18a, benzoimidazol-2-one 18b, and S-(2-amino-phenyl) N,N-dimethylthiocarbamate 19 respectively. On the other hand reaction of chloroformamidinium salts 1a-e with 3-benzyl-2-hydrazinoquinoxaline 3 and 1-hydrazinophthalazine hydrochloride 4 in the presence of triethylamine as a base, afforded the [1,2,4]triazolo derivatives 6 and 7 respectively in good yield and purity. These triazole derivatives were formed due to the strong tendency towards heterocyclization and substitution of dimethylamine group as a better leaving group.
Substituted guanidines: Introducing diversity in combinatorial chemistry
Del Fresno, Montserrat,El-Faham, Ayman,Carpino, Louis A.,Royo, Miriam,Albericio, Fernando
, p. 3539 - 3542 (2007/10/03)
(matrix presented) The guanidine moiety is an important motif present in many biologically active compounds. Fully substituted guanidines are of key importance for the development of bioactive molecules. The present paper reports on an efficient procedure for the direct solid-phase conversion of amines to fully substituted guanidines under very mild conditions.
