Crystal and molecular structure of 3-dimethylaminobenzoic acid

The title compound C₉H₁₁NO₂ is triclinic, space group P¯1, with the cell dimensionsa=7.022(1),b=7.476(2),c=8.957 (1) Å,=87.02(2),=110.88(1),=99.10(1)°,V=433.8(4) ų,Z=2,M _r =165.2,Do=1.27,Dx=1.26 mg/m³,F(000)=176,T=293 K,R=0.057 for 939 observed reflections. The molecules are packed as centrosymmetric hydrogen bonded dimers with an O-HO distance of 2.626(3) Å. The COOH group is rotated by 1.7(1)° about the exocyclic C(1)-C(7) bond out of the benzene ring plane. The molecules lie on (0 2-1) plane for which thed value is found to be 3.378 Å which is very close to the mean separation between the parallel packed benezene rings [3.347(4) Å]. The entire molecule is planar except for the two methyl groups attached to the nitrogen atom. The N atom is free from any binding of either type C-HN or O-HN.N. C. L. Communication No. 4699.     

Molecular rearrangement of photoparthenin by BF3-etherate-acetic acid complex: X-ray crystal structure of a novel product

The structure of a novel compound,Iupac name: bicyclo [2.4.0]-octa-1,3-dimethyl-2,3-pentan-9-methylene-8, 10-butan-diolide, which resulted on treatment of photoparthenin with BF₃-etherate acetic acid, has been established uniquely by X-ray crystallography. C₁₅H₁₈O₄ is orthorhombic, space group P2₁2₁2₁, with the cell dimensionsa=8.444(1),b=9.964(2),c=16.239(2) Å,V=1366.3(2) ų,Z=4,M _r =262.3,D _o=1.29,D _x=1.28 g cm^–3, F(000)=560,T=293K,R=0.065 for 818 observed reflections. -lactone ring has a skew-boat, -lactone ring has an envelope, and the remaining six-membered ring has a distorted chair conformation. The four-membered ring is nonplanar. There are two intramolecular and one intermolecular short C-HO interactions 2.819, 2.834, and 3.259 Å, respectively, which stabilize the crystal structure.N.C.L. Communication No. 4583.     

Synthesis and characterization of deep eutectic solvents (five hydrophilic and three hydrophobic), and hydrophobic application for microextraction of environmental water samples

Hydrophilic and hydrophobic deep eutectic solvents (DESs) as “green” solvents were applied in this study for the microextraction of environmental samples. A series of DESs (five hydrophilic and three hydrophobic) were synthesized and characterized by Fourier transform infrared spectroscopy. Physicochemical property parameters of eight DESs including water solubility, density, conductivity, and freezing point were assessed. Compared with the performance of five hydrophilic DESs in water phase, the three hydrophobic DESs were more suitable for application in dispersive liquid-liquid microextraction for the determination of sulfonamides in water sample. In dispersive liquid-liquid microextraction process, analytical parameters including type and volume of extraction solvent, extraction time, and pH of water sample were investigated. Under optimum conditions, 60 μL of hydrophobic DESs was used for extraction for 2 min in pH = 7.0 sample. The linear ranges were 0.05–5.0 μg/mL for the four sulfonamides with the correlation coefficients in the range of 0.9991–0.9999. The limits of detection were in the range of 0.0005–0.0009 μg/mL and the limits of quantification were in the range of 0.0019–0.0033 μg/mL. The recoveries of the analytes of the proposed method for the spiked samples were 80.17–93.5%, with the relative standard deviation less than 6.31%. The results indicated that three hydrophobic DESs showed commendable performance for extraction of sulfonamides, and hydrophobic DES-based microextraction method was successfully applied for monitoring sulfonamides in water samples.

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Evaluation of fatty acid/alcohol-based hydrophobic deep eutectic solvents as media for extracting antibiotics from environmental water

Analytical and Bioanalytical Chemistry - Fatty acid/alcohol-based hydrophobic deep eutectic solvents (DESs) have been considered to be eco-friendly alternatives to replace conventional hydrophobic...