Heterocycles medicinal interest

A vast array of piperidine containing cores, both natural and synthetic, are of biological and medicinal interest. These heterocyclic scaffolds have been the subjects of considerable synthetic efforts, especially for the construction of optically active compounds. In this context, Khan et al. reported a catalytic bromodi-methylsulfonium bromide (BDMS) three-component reaction of 1,3-dicarbonyls with aromatic aldehydes and aromatic amines for a facile access to highly functionalized piperidines (Scheme 24) [104]. This strategy is an interesting illustration of... 

These biological activities, combined with the use of these products as starting materials to prepare a- and p-amino acids, alkaloids, heterocycles, taxoids, and other types of compounds of biological and medicinal interest [39—4-7], provide the motivation to explore new methodologies for the synthesis of substances based on the p-lactam core. 

N-Aryl and N-heteroaryl derivatives of aminomethylene malonates are also very useful and fruitful synthons for formation of 4-aminoquinolines used as antimalarials (equation 215), of the anticoccidial 6,7-dialkoxy-4-hydroxyquinoline-3-carboxylates and of antibacterial nalidixic acid derivatives (equation 216). Each of these is an important group of pharmaceuticals, developed in the last twenty years. Because of its medicinal interest this route is widely used for synthesis of quinolines and pyridinofused heterocycles. The chemistry has been comprehensively reviewed in a recent monograph292. Hence, no further details are given here. 

Besides being a key starting material for the preparation of polyorthocarbonates, dichlorodiphenoxy methane is a versatile synthon for the construction of heterocyclic systems of medicinal interest (Ref. 36). Its condensation with cyanamide affords diphenyl cyanocarbonimidate in high yield (Ref. 35) as shown in scheme 38 ... 

Perhaps the greatest value of the Sandmeyer synthesis is the preparation of isatin scaffolds for the generation of compounds of medicinal interest. The ambiphilic nature of isatin allows it to undergo ring forming reactions to produce a variety of heterocyclic systems. Reaction of isatin 33 with substituted isatoicanhydrides 34 to form indoloquinazoline 35,serves as an example. 

FIGURE 11.59 1,2,3,4-Tetrahydro-P-carboline-derived diketopiperazines library. (From Kundu, B., Solid-phase strategies for the design and synthesis of heterocyclic molecules of medicinal interest, Curr. Opin. Drug... 

One of the most common synthetic approaches to the construction of heterocyclic compounds involves the reaction of /3-keto esters with bifunctional nucleophiles. Thus a variety of reactions of (1) with different bifunctional heteronucleophiles, including hydrazine, substituted aminotriazoles, 2-aminopyridines, o-phenylenediamines, and o-aminothiophenol, lead to polynuclear condensed thieno compounds (e.g. 2-8) of potential medicinal interest featuring the pyrazolone, pyrimidinone, benzodiazepine, and benzothiazepine nuclei. Cannabinoid analogs can be prepared through cyclization of the condensation products of (1) with bifunctional oxygenated nucleophiles such as substituted resorcinols. ... 

Microwave-Induced Synthesis of Heterocycles of Medicinal Interests... 

MICROWAVE-INDUCED SYNTHESIS OE HETEROCYCLES OF MEDICINAL INTERESTS... 

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