(E)-3-[(2-Hydroxy-3-methoxybenzylidene)amino]benzoic acid

2-Phenyl­acetic acid–3-{(E)-2-[(E)-pyridin-3-yl­methyl­idene]hydrazin-1-ylidenemeth­yl}pyridine (2/1)

The asymmetric unit of the title 1:2 adduct, C(12)H(10)N(4)·2C(8)H(8)O(2), comprises a single mol-ecule of 2-phenyl-acetic acid and half a mol-ecule of 3-pyridine-aldazine; the latter is completed by crystallographic inversion symmetry. In the crystal, mol-ecules are connected into a three-component aggregate via O-H⋯N hydrogen bonds. As the carboxyl group lies above the plane through the benze...

(E)-3-[(2-Hy­droxy-3-meth­oxy­benzyl­idene)amino]­benzoic acid

In the title compound, C(15)H(13)NO(4), the dihedral angle between the substituted benzene rings is 9.9 (8)°. Part of the mol-ecule (the salicylaldimine segment) is disordered over two sets of sites, with a refined site-occupancy ratio of 0.550 (14):0.450 (14). Intra-molecular O-H⋯N hydrogen bonds form S(6) ring motifs. In the crystal, pairs of O-H⋯O hydrogen bonds link mol-ecules into centrosy...

(E)-3-[(3-Eth­oxy-2-hy­droxy­benzyl­idene)amino]­benzoic acid

In the title compound, C(16)H(15)NO(4), a potential bidentate N,O-donor Schiff base ligand, the benzene rings are inclined to one another by 4.24 (12)°. The mol-ecule has an E conformation about the C=N bond. An intra-molecular O-H⋯N hydrogen bond makes an S(6) ring motif. In the crystal, pairs of O-H⋯O hydrogen bonds link the mol-ecules, forming inversion dimers with R(2) (2)(8) ring motifs. T...

H.P.C. (3-hydroxy-2-phenylcinchoninic acid) in rheumatoid arthritis.

Urinary 4-hydroxy-3-methoxymandelic (vanillylmandelic) acid, 4-hydroxy-3-methoxyphenylacetic (homovanillic) acid, and 5-hydroxy-3-indoleacetic acid determined by liquid chromatography with electrochemical detection.

We describe a simple liquid-chromatographic assay of urinary 4-hydroxy-3-methoxymandelic (vanillylmandelic) acid, 4-hydroxy-3-methoxyphenylacetic (homovanillic) acid, and 5-hydroxy-3-indoleacetic acid with electrochemical detection, with direct injection of the sample. The first two analytes are measured simultaneously; 5-hydroxy-3-indoleacetic acid is measured separately. Chromatographic condi...