Adsorption Characteristics of Pb(II) and Cr(III) onto C‐4‐Methoxyphenylcalix[4]Resorcinarene in Batch and Fixed Bed Column Systems

A study on the adsorption characteristics of Pb(II) and Cr(III) cations onto C‐4‐methoxyphenylcalix‐[4]resorcinarene (CMPCR) in batch and fixed bed column systems has been conducted. CMPCR was produced by one step synthesis from resorcinol, 4‐methoxybenzaldehyde, and HCl. The synthesis was carried out at 78 °C for 24 hours and afforded the adsorbent in 85.7% as a 3:2 mixture of C_4ν:C_2ν isomer. Most parameters in batch and fixed bed column systems confirm that CMPCR is a good adsorbent for Pb(II) and Cr(III), though Pb(II) adsorption was more favorable than that of Cr(III). The adsorption kinetic of Pb(II) and Cr(III) adsorptions in batch and fixed bed column systems followed a pseudo 2ⁿ order kinetics model. The rate constant of Pb(II) was higher than that of Cr(III) in the batch system, but this result was contrary to the result obtained in a fixed bed column system. Desorption studies to recover the adsorbed Pb(II) and Cr(III) were performed sequentially with distilled water and HCl, and the results showed that the adsorption was dominated by chemisorption.     

Synthesis and Evaluation of Chalcone Derivatives as Novel Sunscreen Agent

Ultraviolet (UV) irradiation is a serious problem for skin health thus the interest in the research to develop sunscreen agent has been increasing. Chalcone is a promising compound to be developed as its chromophore absorbs in the UV region. Therefore, in the present work, we synthesized eight chalcone derivatives through Claisen–Schmidt condensation at room temperature. The evaluation of the optical properties of each chalcone derivatives in the UV region was conducted through spectroscopic and computational studies. The synthesized chalcones were obtained in good yields and they were active in the UV region. The results revealed that more methoxy substituents to chalcone leads toward red shift. All chalcone derivatives have high molar absorptivity value (21,000–56,000) demonstrating that they have the potential to be used as the sunscreen agent. The cytotoxicity assay showed that chalcone derivatives were demonstrating low toxicity toward normal human fibroblast cell, which is remarkable. Therefore, we concluded that the synthesized chalcones in this work were potential to be developed as novel sunscreen agents in real application.     

Effective synthetic routes to activated pyrrolo[3,2,1-hi]indoles

Pyrrolo[3,2,1-hi]indoles have been formed by the aldol cyclisation of 7-formyl-N-indolylacetates. The synthetic sequence incorporates three steps from suitably activated indoles: these are alkylation at nitrogen with a bromoacetic ester, formylation at C7 and an aldol condensation between these two substituents. An X-ray crystal structure of pyrrolo[3,2,1-hi]indole 24 is described.     

Development of aromatic ethers as solvents for a calix[6]arene derivative and extraction of amino acids and proteins

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Calixarene derivatives are excellent host compounds for ionic species in liquid–liquid extraction. However, many studies using...     

Some reactions of 6,8-dimethoxypyrrolo[3,2,1-hi]indoles

Two 6,8-dimethoxypyrrolo[3,2,1-hi]indole carboxylic esters were hydrolyzed and decarboxylated. In an investigation of their electrophilic substitutions, some pyrroloindoles were formylated using the Vilsmeier reagent, and acylated with oxalyl chloride followed by quenching with dimethylamine to give the glyoxylic amides. The electrophilic substitutions occur at the C2 or C4 position (α to the nitrogen atom) rather than the C1 or C5 position (β to the nitrogen atom). Four of the formyl and acyl products were reduced to the corresponding methanol derivatives. These compounds reacted on treatment with a range of acids, but pure products could not be separated from the complex mixtures.     

Synthetic approaches to activated pyrrolo[3,2,1-hi]indoles: synthesis of 6,8-dimethoxy pyrrolo[3,2,1-hi]indole

6,8-Dimethoxypyrrolo[3,2,1-hi]indole 25 has been formed by the dehydrogenation of the related tetrahydro compound 23, which in turn was formed by reduction of the related isatin 22. Approaches to achieve the cyclisation of N-hydroxyethylindoles, N-dimethylacetamidoindoles, and C7-substituted chloroacetylindoles were unsuccessful.