Yttrium and heavy lanthanide complexes is synthesised with 2, 4-dimethoxybenzoic acid and thermal and spectral features is studied. In the case of the electron-rich aromatic system 2,4-dimethoxybenzoic acid reduction of the intermediate HOBt ester is slow, and good.
Crystallise the acid from water and dry it in a vacuum desiccator over H2SO4.. The S-benzylisothiuronium salt has m 158-159o (from CHCl3). [Beilstein 10 H 379, 10 I 177, 10 II 252, 10 III 1371, 10 IV 1422.] Aromatic acid impurities (to <0.05%) can be removed via the (±)--methylbenzylamine salt as described for 2,4-dichlorobenzoic acid [Ley & Yates Organic Process Research & Development 12 120 2008.]
