The bridge-substituted calix[4]arene carboxylic acid, 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetramethoxy-calix[4]arene-2-carboxylic acid (1), can be readily converted to various esters 2-4 and reduced to the alcohol 5, which reacts with methyl iodide to give the ether 6. The alcohol can be dansylated to give 7, the fluorescence of which is selectively quenched by Cu(II) in acetonitrile. An at...

The conversions of vanillic acid and O-benzylvanillic acid to vanillin were examined by using whole cells and enzyme preparations of Nocardia sp. strain NRRL 5646. With growing cultures, vanillic acid was decarboxylated (69% yield) to guaiacol and reduced (11% yield) to vanillyl alcohol. In resting Nocardia cells in buffer, 4-O-benzylvanillic acid was converted to the corresponding alcohol prod...

Methods to reduce the carboxylic acid moiety in 3-carboxy-2,2,5,5-tetramethylpyrrolin-1-oxyl to an alcohol as an intermediate toward the corresponding aldehyde have been explored and an improved method has been developed.

By DFT calculation, we found that acid-catalyzed carboxylic acid esterification and ester hydrolysis are brief two-step reactions. First, the carboxylic acid hydroxyl-oxygen or ester alkyl-oxygen is protonated, which generates a highly active acylium ion. The protonation requires an activation energy (Ea) of 4-10 kcal mol(-1), and is the rate-controlling step of the esterification or hydrolysis...

Application of SiO2@FeSO4 nanocomposite as a new nanocatalyst in reduction area was investigated. Carboxylic acid simple and convenient reduction to alcohol by 0.75 mol of the nanocomposite, 3 mol sodium borohydride (NaBH4) as reduction reagent under a solvent-free condition at 30-65 min. The reaction happens in two stages - first to form an aldehyde and the...

The carboxyl functional group is represented as –COOH and is the end product of alcohol oxidation. The term carboxylic acid is little special in the sense that it represents two functional groups; first a carbonyl group and second hydroxyl group. One can say that in the carboxyl group a hydroxyl group is bonded to a carbonyl (>C = O) group. It is often represented as CO2H or COOH. Carboxylic ac...

A multi-channel piezoelectric quartz crystal sensor with a homemade computer interface was prepared and employed in the present study to detect mixture of organic molecules. Back propagation neural network (BPN) was used to distinguish the species in the mixture organic molecules and multivariate linear regression analysis (MLR) was used to compute the concentration of the species. A six-channe...

Herein, we report the occurrence of four new compounds in ethanolic extract Albizia coriaria Welw ex. Oliver leaves along with other previously reported this species. The were isolated and characterized using column chromatography, Fourier Transform Infrared (FTIR) gas chromatography/mass spectrometry. FTIR spectrum showed phenolic OH stretching (3362.30 cm-1), C=O (1660.08 CO (1369.46 cm-1 131...

the synthesis of aryl amides via the reactions of carboxylic acids and isocyanides in methanol was carried out in 78-95% yields under ultrasound irradiation. the method has wide applicability, and the protocol is mild, fast and efficient compared to the existing methods based on silent conditions.

In this study the effects of probiotic bacteria and inulin addition on microbiological qualities, volatile aroma components sensory properties during ripening low-fat Tulum cheeses were examined. Adding to improved components, properties. The enhanced growth viability bacteria. total quantities alcohol, aldehyde, carboxylic acid, hydrocarbon, terpene increased as due maturation. During storage,...