Erratum to “Reaction of ferrocenecarboxylic acid with N,N′-disubstituted carbodiimides: synthesis, spectroscopic and X-ray crystallographic analysis of N,N′-disubstituted N-ferrocenoylureas and identification of a one-pot coupling reagent for the formation of ferrocenecarboxamides in a non-aqueous solvent” [J. Organomet. Chem. 689 (2004) 1472–1480]

The reaction of (Sp)-2-(diphenylphosphino)ferrocenecarboxylic acid with carbodiimide reagents: Characterisation of the acid anhydride and urea products

“…The C@O carbons resonate at d C 154.70 (NC(O)N) and 171.24 (C(O)N), the latter as a doublet due to scalar coupling with the proximal phosphorus atom ( 3 J PC = 2 Hz). The observed chemical shifts compare favourably with those reported for FcC(O)N(Cy)C(O)NHCy (Fc = ferrocenyl) [11]. The 31 P{ 1 H} NMR spectrum of (S p )-2a displays a single resonance at d P À20.0, indicating the presence of an unchanged diphenylphosphino group [4].…”

“…However, the tautomerism of cyclic forms of EDC [11,23] or a preferred configuration of the O-acyl-urea intermediate may play some role.…”

“Tail–Tail Dimerization” of Ferrocene Amino Acid Derivatives

“…Anhydrides are often encountered in peptide synthesis during activation of carboxylic acids by DCC, EDC [1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide] or acid chlorides 16,20c. We have recently reported the activation of Fca as an acid fluoride by cyanuric fluoride for amide coupling,13 similar to the formation of Fc‐COF from Fc‐COOH 18.…”

Acylurea Pyrolysis - Thermolysis of N,N′-Disubstituted Ferrocenoylureas as a New Way to N-Monosubstituted Ferrocenecarboxamides

“…This method is also applicable for the corresponding ferrocenecarboxylic acid derivatives. [1][2][3] Ferrocenoylfluoride merits special consideration, which can be obtained from ferrocenecarboxylic acid and cyanurfluoride in remarkably good yield. 4 Furthermore, carbodiimides are employed as trustworthy coupling agents to form amides directly from carboxylic acids and amines under particularly mild conditions.…”

“…2 The isocyanate route gives poor yields and mixtures of products, 11 while the carbodiimide-mediated direct reaction of ferrocenecarboxylic acids with amides is generally unsuccessful. 2,3,14,15,19 Among an abundance of carbodiimides tested, EDC alone was able to promote the desired direct reaction. 3 When ferrocenecarboxylic acid and 1,1¢-ferrocenedicarboxylic acid were reacted with carbodiimides, N,N¢-disubstituted ferrocenoylureas were obtained in good yields.…”