Novel frontiers through nitrogen substitution at 6th, 10th and 11th position of artemisinin: Synthetic approaches and antimalarial activity

Malaria pertains to an array of catastrophic illnesses spurred on by the Plasmodium spp. Artemisinin (ART) is currently prescribed in conjunction with another medication as part of therapeutic regimens for acute malaria. These currently prescribed pharmaceuticals have been around for a while, even after lack of required thermos-metabolic stabilities, alongside fresh proclaims about surfacing resistance and neurotoxicity linked with sequential administration of such combination therapies. Over the years, ARTs seem to have gained popularity through the accelerated reduction in parasitaemia, thus dictating use of differentially stable ART derivatives, in combination or alone, to control the proliferation of malaria. The endoperoxide bridge in the ART pharmacophore plays a non-negotiable role in its action against multiple stages in the parasitic life cycle. However, shorter half-lives and limited bioavailability tend to open doors for another class of endoperoxides. Nitrogen substitution at 6th, 10th and 11th positions of ART draws attention as the best replacements through their disparate stabilities and inability to demonstrate in vivo hydrolytic decomposition into DHA. Discussions pertaining such azaartemisinins and aminoartemisinins reported over the past 30 years have been strongly focused upon, on account of their synthetic methodologies and antimalarial efficacies, in order to assign future candidature to the meritorious moiety.

Recent advances in the synthesis and antimalarial activity of 1,2,4-trioxanes

The increasing resistance of various malarial parasite strains to drugs has made the production of a new, rapid-acting, and efficient antimalarial drug more necessary, as the demand for such drugs is growing rapidly. As a major global health concern, various methods have been implemented to address the problem of drug resistance, including the hybrid drug concept, combination therapy, the development of analogues of existing medicines, and the use of drug resistance reversal agents. Artemisinin and its derivatives are currently used against multidrug- resistant P. falciparum species. However, due to its natural origin, its use has been limited by its scarcity in natural resources. As a result, finding a substitute becomes more crucial, and the peroxide group in artemisinin, responsible for the drugs biological action in the form of 1,2,4-trioxane, may hold the key to resolving this issue. The literature suggests that 1,2,4-trioxanes have the potential to become an alternative to current malaria drugs, as highlighted in this review. This is why 1,2,4-trioxanes and their derivatives have been synthesized on a large scale worldwide, as they have shown promising antimalarial activity in vivo and in vitro against Plasmodium species. Consequently, the search for a more convenient, environment friendly, sustainable, efficient, and effective synthetic pathway for the synthesis of 1,2,4-trioxanes continues. The aim of this work is to provide a comprehensive analysis of the synthesis and mechanism of action of 1,2,4-trioxanes. This systematic review highlights the most recent summaries of derivatives of 1,2,4-trioxane compounds and dimers with potential antimalarial activity from January 1988 to 2023.

Catalytic synthesis of benzannelated macrocyclic di- and triperoxides based on phenols

An efficient method for the synthesis of benzannelated macrocyclic di- and triperoxides by cyclocondensation of aromatic compounds with bis-hydroperoxides and formaldehyde in the presence of lanthanide catalysts has been developed.