2- Hydroxy-3-pyridine carboxaldehydes

Condensation of tren with 2,3-dihydroxybenzaldehyde, sal (52) (or derivatives), acac, 2-hydroxy-acetophenone (or derivatives), pyridine carboxaldehydes, pyrrole carboxaldehydes and... 

The IR spectra of Co(II), Ni(II) and Cu(II) complexes of Schiff bases derived from condensation of 2-pyridine-carboxaldehyde with DL-alanine, DL-valine and DL-phenylalanine, show that all act as uninegative, bidentate ligands.507 Similar data for complexes of the heterocyclic Schiff base LH2 derived from 1 -amino-5-benzoyl-4-phenyl-li/-pyrimidin-2-one and 3-hydroxy-salicylalde-hyde show that the ligand is tridentate (0,N,0) in M(LH)2 (M = Co, Cu, Zn), but bidentate (N,0) in Ni(LH2)2Cl2.508... 

Prien et al. [18] have synthesized 3-hydroxy-2-methylidene propionic acids on hydrox-yethyl resin via a Baylis-Hillman reaction by using aldehydes bearing electron-withdrawing groups, for example nitrobenzaldehyde, trifluoromethylbenzaldehyde and pyridine-carboxaldehyde. 

Table 27. Selected examples of correlation between observed and calculated UV transitions (Del Bene and Jaffe). (Other studied compounds include benzene, pyridine, 1,2-diazine, 1,3-diazine, 1,4-diazine, cyclopentadienide ion, pyrazole, imidazole, 2-pyrrole-carboxaldehyde, furfural, benzonitrile, nitrosobenzene, phenol, phenoxide ion, pyridinium ion, 1-hydroxy-pyridinium ion, 2-cyano-pyridine, 3-cyano-pyridine, 4-cyano-pyridine, 2-amino-pyridine, 3-amino-pyridine, 4-amino-pyridine.)...

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