Reagent utilized in amide bond synthesis and other coupling reactions. Prepn: G. Errera, Gazz. Chim. Ital. 25 II, 25 (1895). Crystal structure: P. G. Jones, Acta Crystallogr. E59, 1951 (2003) DOI. Early use in peptide synthesis: G. W. Anderson et al., J. Am. Chem. Soc. 85, 3039 (1963) DOI; and alternative prepn method: eidem, ibid. 86, 1839 DOI (1964). Synthetic applications: A. Cecchetto et al., Tetrahedron Lett. 43, 3605 (2002) DOI; A. Schulze, A. Giannis, Adv. Synth. Catal. 346, 252 DOI (2004); M. A. Mironov et al., Tetrahedron Lett. 46, 3957 (2005) DOI; H.-C. Ma, X.-Z. Jiang, J. Org. Chem. 72, 8943 (2007) DOI PubMed. Reviews: D. W. Knight in Encyclopedia of Reagents for Organic Synthesis 4, L. A. Paquette, Ed. (John Wiley & Sons, New York, 1995) pp 2780-2781; P. A. Wang, Synlett 2008, 2384-2385 DOI.