MAOS and Medicinal Chemistry: Some Important Examples from the Last Years

Abstract

This review aims to highlight microwave-assisted organic synthesis as applied to medicinal chemistry in the last years, showing some reactions performed under microwave irradiation for the synthesis of distinct structurally molecules of biological interest, divided into the following groups: antineoplastics, anti-inflammatory, antimicrobial agents, antivirals, agents for the treatment of neglected diseases and central nervous system-acting prototypes.

Synthesis, Bioevaluation and Structural Study of Substituted Phthalazin-1(2H)-ones Acting as Antifungal Agents

“…Equimolar amounts of benzalphthalides B14 – B16 and methylhydrazine were mixed with SiO 2 (10 mol) and irradiated at 350 W during 1–6 min, the mixture was percolated with ethyl acetate and the crude purified by column chromatography to provide the desired phthalazinones 20 – 22 in 60–70% yield. It is interesting to note the advantages of the MW-based procedure that led to cleaner reactions products in these cases and have previously served to prepare different phthalazine derivatives [17]. Indeed, when method A was applied to the dichlorinated benzalphthalides B14 – B16 more complex reaction mixtures were obtained, in which, apart from the expected phthalazinones 20 – 22 , in lowered yields, several compounds (not reported here) derived from chlorine substitution by methylhydrazinyl groups were also found.…”

Microwave Irradiation and Formamide: A Perfect Match for Ultrafast Carbamoylation via Radical Reactions

“…Over the past decades, microwave irradiation has been extensively used in organic chemistry as a synthetic tool that fully adheres to the principles of green chemistry. − Among the environmentally benign processes for the synthesis of organic molecules, cascade reactions occupy a prominent place since they allow the formation of several bonds in one-pot protocols, have high atom economy, are facile to operate, and reduce the steps of workups, lowering the generation of waste. − Despite the advantages outlined above, radical cascade reactions triggered by microwave irradiation have scarcely been explored.…”

Novel Microwave-Assisted Synthesis of the Immunomodulator Organotellurium Compound Ammonium Trichloro(dioxoethylene-O,O')tellurate (AS101)

“…Some excellent reviews and books are present in the literature [23–32]. In summary, the capacity of microwaves to couple energy directly to the material is the primary advantage of MW processing as compared to conventional techniques, allowing shorter reaction times, uniform heating, higher yields and often enhancing material properties and product purities by reducing unwanted side reactions.…”

“…Over recent years, heating and driving chemical reactions by microwave (MW) energy has been a significant interest in the scientific community, in particular applied to microwave-assisted organic synthesis (MAOS), medicinal chemistry, drug discovery and polymer science. Some excellent reviews and books are present in the literature [ 23 – 32 ]. In summary, the capacity of microwaves to couple energy directly to the material is the primary advantage of MW processing as compared to conventional techniques, allowing shorter reaction times, uniform heating, higher yields and often enhancing material properties and product purities by reducing unwanted side reactions.…”

“…The extensive use of MW irradiation for the synthesis of molecules of pharmacological interest has contributed to improve the access to different chemical scaffolds by applying new methodologies and techniques, specially based on the benefits related to better yields and shorter reaction times. Clearly MW irradiation is becoming a fundamental tool for optimizing key steps in the synthesis of target compounds within the field of drug discovery [ 23 , 33 , 34 , 37 , 38 ].…”