Tyrrell, Elizabeth; Brawn, Peter; Carew, Mark; Greenwood, Iain published an article on January 19 ,2011. The article was titled 《An expedient conversion of α-amino acids into Weinreb amides using COMU as a coupling agent》, and you may find the article in Tetrahedron Letters.Electric Literature of C13H26N2O4 The information in the text is summarized as follows:
The use of COMU, as a non-hazardous partner, in the coupling of N-Boc α-amino acids with N-methoxy-N-methylamine to afford the corresponding Weinreb amides is discussed. From a practical point of view the reaction can be monitored visually by virtue of the color change associated with the conversion of substrates (yellow) into the products (orange). As the byproducts of the reaction are conveniently water-soluble, the products are isolated relatively pure and with minimal racemization. These factors coupled with the short reaction time make this a very useful procedure. In the experiment, the researchers used (S)-N-Methyl-N-methoxy-2-(tert-butoxycarbonylamino)-4-methylpentanamide(cas: 87694-50-6Electric Literature of C13H26N2O4)
(S)-N-Methyl-N-methoxy-2-(tert-butoxycarbonylamino)-4-methylpentanamide(cas: 87694-50-6) belongs to amides. Because of the greater electronegativity of oxygen, the carbonyl (C=O) is a stronger dipole than the N–C dipole. The presence of a C=O dipole and, to a lesser extent a N–C dipole, allows amides to act as H-bond acceptors.Electric Literature of C13H26N2O4 In primary and secondary amides, the presence of N–H dipoles allows amides to function as H-bond donors as well.
Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics