Current Organic Chemistry - Volume 19, Issue 15, 2015

Due to its unique anatomy, drug delivery to eye structures has always been problematic. Many efforts have been addressed to enhance ocular bioavailability by lowering non-specific interactions between drug and tissue, increasing drug stability or increasing the residence time in the case of topical drugs. In this context, nanotechnology has been a very helpful tool for developing suitable drug delivery systems. More specifically, different kinds of strategies in this field have been proposed to overcome the problems related to ocular administration. However, the success of a nanoparticulated system relies on the correct choice of the material which it is made of. Based on these statements, the present article offers a review of the most important biomaterials employed in nanostructured systems for ocular drug delivery, especially those designated to delivery to the ocular surface and their impact on the final activity of such systems.

Despite incredible advancement made in recent years, treatment of cancer still remains the most challenging task for the mankind. The new small molecule therapeutic drugs are more specific, exhibit better therapeutic efficacy and mostly contain scaffolds of β-lactam, sulfonamide, quinoline, quinazoline, quinoxaline, purine, pyrimidine, resorcinol, pyrazole/isoxazole, benzamide etc. The structure-activity relationships of different pharmacophores that have been reported to potently inhibit cell growth of human tumour cell lines are constantly being investigated. Development of products of natural origin can also prove effective without submitting to harmful radiation and chemotherapy treatments. Under these circumstances, the practicing organic chemists are greatly facing the challenge of designing new and leading anti-cancer drugs based on natural products and scaffolds of potent pharmacaophores. The review intends to cover new approach of anti-cancer drug design using natural and synthetic pharmacophores. The plausible synthetic routes to major drugs for oncology that were approved recently by Food and Drug Administration (FDA) are also discussed.

The Birch reduction is unique, in synthetic approaches, due to the adaptable substitution patterns of the substituted cyclohexa-1,4- and 1,3-dienes, particularly enol ethers. Birch reduction as a key and sometimes as the only reduction tool has found several applications in total synthesis of several natural occurring compounds. This name reduction is very important and quite useful for reduction of aromatic and none-aromatic moieties. It is particularly useful in aromatic compounds due to its selectivity of reduction of certain double bonds, which are present in one of the starting materials in multi-step total synthesis. It is also applicable when further reduction of nonaromatic moieties as a part of natural product structures, is required. In this report, we try to highlight the applications of this reaction as a key step in the total synthesis of natural products. It covers the applications of Birch reduction in total synthesis of naturally occurring compounds from 2003 till date.

In the framework of our general interest on the reactivity and on the pharmacological activity of heterocyclic compounds, we have examined the behaviour of some variously substituted 5- and 6-nitroindazoles. Remembering that nitroreduction processes are often essential steps for their biological activity we have collected NMR, ESR, and CV data and carried out DFT computations to gain a deep picture of electronic distribution and of reduction processes as a function of the chemical structure of the examined substrates. Interestingly, DFT computations have furnished strong support to experimental data. Moreover, the comparison between the general behaviour of 1- and 2-alkyl substituted nitroindazoles has furnished further confirmation to the known different electronic distribution in these two classes of compounds, while CV data have evidenced the ability of N1-H nitroindazoles to give rise to the formation of a dimer.