In the title compound, C(12)H(17)NO(4)S(2), the carboxyl groups link the mol-ecules into centrosymmetric dimers through O-H⋯O hydrogen bonds. An N-H⋯O hydrogen bond between the NH group of the l-methio-nine unit and a neighbouring carboxyl group, together with a complementary C-H⋯O contact to one O atom of the sulfonyl group, link the dimers into one-dimensional chains along the crystallographi...

A new procedure for analyses for tryptophan in proteins and glycoproteins is described. The method utilizes ptoluenesulfonic acid as the catalyst for hydrolysis and the amino acid analyzer for the quantitative estimation of tryptophan. The hydrolysis of proteins is carried out in 3 N p-toluenesulfonic acid containing 0.2 % 3-(Z-aminoethyl)indole in evacuated sealed tubes at 110” for 22, 48, and...

The complete mol-ecule of the title compound, C(14)H(18)O(6), has a center of inversion at the centroid of the benzene ring and the asymmetric unit contains one half-mol-ecule. The conformation of the side chain is anti [C-C-C-C = -171.40 (17)°]. In the crystal, pairs of head-to-head carb-oxy-lic acid O-H⋯O hydrogen bonds link the mol-ecules into infinite zigzag chains propagating along [130]. ...

Two mol-ecules of the title compound, C(15)H(15)NO(3), are linked by a pair of O-H⋯O(carbon-yl) hydrogen bonds over a centre of inversion to form a hydrogen-bonded dimer. With respect to the -C(=O)-N(OH)- unit, the methoxy-substituted ring is twisted by 42.2 (1)°, whereas the methyl-substituted ring is twisted by 52.2 (1)°.

salicylic acid is an important organic acid in plants rhizosphere soil exuded in the phosphorus (p) deficiency condition. to study the sorption behavior of p in the presence of salicylic acid, a batch experiment was conducted with different concentrations of salicylic acid (0, 2, 5 and 10mm) and p (0- 45 mg p/l) in a calcareous soil. the results showed that application salicylic acid decreased ...