In the title compound, C(13)H(11)NO(4)S, the dihedral angle between the planes of the benzene ring and the carboxyl group is 13.7 (1)°. The mol-ecular structure contains intra-molecular N-H⋯O and C-H⋯O hydrogen-bonding inter-actions, while the crystal packing is stabilized by C-H⋯O and O-H⋯O hydrogen bonds and C-H⋯π inter-actions. The O-H⋯O hydrogen bonds form a cyclic dimer, with graph-set mot...

The title compound, C(10)H(10)O(4), crystallizes with the well-known carb-oxy-lic acid dimer-forming R(2) (2)(8) hydrogen-bond motif. Chains approximately parallel to (-1-12) are then built through C(methyl-ene,phen-yl)-H⋯O(carbon-yl) inter-actions [C(6) and C(8) motifs] with one (meth-yl)C-H⋯π inter-action providing inter-planar binding. The weakness of the latter inter-action is consistent wi...

The title compound, C5H9NO4·H2O, is an isomer of the α-amino acid glutamic acid that crystallizes from water in its zwitterionic form as a monohydrate. It is not one of the 20 proteinogenic α-amino acids that are used in living systems and differs from the natural amino acids in that it has an α-methyl group rather than an α-H atom. In the crystal, an O-H⋯O hydrogen bond is present between the ...

The title compound, C(4)H(3)BrO(4), was obtained from a solution of meso-2,3-dibromo-succinic acid and vanadium(IV) oxide. The crystals are isostructural with chloro-maleic acid and the mol-ecule has two geometrically different carboxyl groups, one of which has delocalized C-O bonds and is essentially coplanar with the olefinic bond plane [give dihedral angle 15.08 (16)°], whereas the other has...

Nano silica sulfuric acid as a solid acid, was described to be an effective catalyst for one-pot three-component reaction of kojic acid, aryl aldehydes and indoles for the preparation of 2-substituted aryl (indolyl) kojic acid derivatives. The catalyst was prepared by combination of chlorosulfonic acid to nano silica gel. The size of nanoparticles were observed with SEM.All prepared compounds w...

The title compound, C(8)H(9)NO(4)S, is of inter-est as a precursor to biologically active sulfur-containing heterocyclic cmpounds. The crystal structure displays the classical O-H⋯O inter-molecular hydrogen bonding typical for carboxylic acids forming dimers. Symmetry-related dimers are, in turn, linked through head-to-tail pairs of inter-molecular N-H⋯O inter-actions, giving rise to a zigzag c...