154561-21-4Relevant articles and documents
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.
3-Hydroxy-4-oxo-3,4-dihydro-5-azabenzo-1,2,3-triazene
Carpino, Louis A.,Xia, Jusong,El-Faham, Ayman
, p. 54 - 61 (2007/10/03)
The known but long-neglected compound HODhat was shown to be in certain situations a useful peptide coupling additive. Uronium and phosphonium salts with HODhat built into the system were also useful stand-alone coupling reagents. Comparisons with related additives and coupling reagents showed that the new systems were sometimes more and sometimes less effective than previously described systems in the case of stepwise and segment couplings. Applications to assembly of the model decapeptide ACP showed that HDATU was far more effective than HDTU and more effective than HATU under some conditions.
Comparison of the effects of 5- and 6-HOAt on model peptide coupling reactions relative to the cases for the 4- and 7-isomers
Carpino, Louis A.,Imazumi, Hideko,Foxman, Bruce M.,Vela, Michael J.,Henklein, Peter,El-Faham, Ayman,Klose, Jana,Bienert, Michael
, p. 2253 - 2256 (2007/10/03)
(equation presented) Synthesis of 5- and 6-HOAt has completed the full set of the four HOAt isomers derived from HOBt by insertion of a single nitrogen atom in the benzenoid nucleus. Comparison of the reactivity of all four isomers in model peptide coupling reactions has confirmed the unique character of the 7-isomer in promoting selectivity and maintaining configuration at the reactive carboxylic acid residue.