Mini-Reviews in Organic Chemistry - Volume 13, Issue 4, 2016

This review presents synthesis methods for halogenated calix[4]arenes at the upper rim and in meta-position of phenolic unit as well as at the lower rim by substitution of hydroxyl group by halogen atom; methods for introducing the atom of iodine, bromine and chlorine into the molecule of calix[4]arenes; the advantages and disadvantages of each method.

With the improvement of living standards and dietary habits, the flavor and quality of food are highly sought after; therefore people are pursuing to experi- ence more delicious food. Many researchers in food flavor area are seeking mole- cules which make food more delicious and healthier. More and more investigators are studying the relation between taste molecules and gustation receptor. Kokumi taste is a kind of sensory feeling, such as thickness, mouthfulness, complexity, and increasing the continuity of the perception of food taste at the same time. As a new defined taste, in the sensory area, kokumi taste is being studied. This article deals with the finding of kokumi taste, detection of kokumi substances, and discussing kokumi taste mechanism. The major section of this review will relate to the kokumi- tasting components which have been published lately, such as y-glutamyl peptides etc.

Tuberculosis (TB) is one of the major emerging universal public health prob- lems. In 1993, WHO has declared TB as a global emergency, but its control is hampered due to multidrug resistance (MDR), i.e., Mycobacterium tuberculosis (M. tuberculosis) strains that are resistant to isoniazid (INH) and rifampicin (RIF), the two widely used drugs for treating TB. Recently, extensively drug-resistant (XDR) TB has been reported, as these are resistant not only to INH and RIF, but also to any fluoroquinolone drug in ad- dition to one of the three injectable second-line drugs (amikacin, kanamycin, and capreo- mycin). Following the invention of drugs having antitubercular (anti-TB) activity, multi- drug therapy has been responsible to control TB. Developments in molecular biology due to sequencing of the genome of M. tuberculosis have improved the understanding of anti- TB drug resistance. However, better information of drug resistance and molecular biology aspects have im- proved the current techniques of rapid detection of TB that will help to stimulate exploration of new targets for drug action. This review summarizes the molecular biology of drug resistance to the main classical drugs as well as drugs that are currently under developmental stage.

Water pollution levels are rising worldwide, so new tools that can over- come the harmful effects of pollutants to the environment and living organisms are welcome. In this context, metalloporphyrins (MePs) mimicking cytochrome P-450 enzymes can contribute to the production of metabolites and help to elucidate bio- transformation processes. MePs can promote chemo-, regio-, and stereoselective transformations under mild conditions, which is highly desirable when investigating the metabolism of drugs or pesticides that currently contaminate natural waters. MeP models can be tailored by introducing electrophilic groups into different posi- tions of the porphyrin ring and by choosing suitable oxygen donors to activate the catalyst and generate the high-valence intermediate species. This mini-review aims to show a recent breakthrough in the use of MePs as a powerful tool to predict which metabolites arise during biotransformation assays. It also aims to highlight the versatility of such models regarding the current challenges in catalytic conversion of xenobiotics.

The technique involving ultrasound is a very modern and versatile method used in the last decades for the synthesis of organic compounds containing phosphorus. The use of ultrasonication in phosphorus chemistry was described in many scientific papers in last years. Nowadays this method is still developing. Until now, it was used for transesterification reactions, coupling reaction, production of nanocomposites, synthesis of different compounds for anticorrosion coatings, synthesis of polycyclic phosphonate resins and so on. This technique is of great interest, because first of all, it is a green method. As we will describe further in this review, in some cases the ultrasonication also improved the products yield, in comparison with the classical approaches.

The protection of carbonyl compounds plays an important role during multistep syntheses in organic, medicinal, carbohydrate, and drug design chemistry. Among various carbonyl protecting groups, 1,3-oxathiolane, 1,3-dioxolane, 1,3- dithiolane are important because of their stability and the preparation ease. This review summarizes and highlights methods for the synthesis of S,O-, O,O- and S,S-cyclic acetals based on transformations of α,β-enals.

Tanshinone IIA is a principal constituent of a dried root or rhizome of Salvia miltiorrhiza Bunge (Danshen or Tanshen in Chinese). This plant has been widely used as traditional Chinese medicine for treatment of several diseases for thousands of years. This review describes biological activities reported for tanshinone IIA.

Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) is a widely known magical heterocyclic compound with anti-inflammatory, anti-oxidant and cytopro- tective activity. It acts as a mimic of glutathione peroxidase; used for the treatment of Alzheimer's disease and HCV disorder as well as effective against Clostridium difficile infections. Since its first synthesis in 1924, relatively a few synthetic ap- proaches have been reported for such a versatile drug. It may be due to the presence of Se-N linkage, which is quite a challenging step for synthetic chemists. The cycli- zations via primary amines, free radical synthesis and transition metal catalyzed syn- thesis are the widely employed routes for the synthesis of ebselen and its derivatives. This review aims to provide readers an insight into the past and present synthetic approaches towards ebselen and its derivatives.