Synthesis, biological activities, and future perspectives of steroidal monocyclic pyridines.

Steroidal pyridines are a class of compounds that have been the subject of extensive research in recent years due to their potential biological activities. The introduction of a pyridine ring into the steroid skeleton can significantly alter the chemical and biological properties of the compound, making it more potent and/or selective for a particular target. Different synthetic methods have been developed for the preparation of steroidal pyridines.

Insights into the medicinal chemistry of heterocycles integrated with a pyrazolo[1,5-]pyrimidine scaffold.

Pyrazolo[1,5-]pyrimidines are the dominant motif of many drugs; for instance, zaleplon and indiplon are sedative agents and ocinaplon was identified as an anxiolytic agent. The importance of this class of compounds lies in its varied and significant biological activities, and accordingly, considerable methods have been devised to prepare these compounds. Hence, other derivatives of this class of compounds were prepared by substitution reactions with different nucleophiles exploiting the activity of groups linked to the ring carbon and nitrogen atoms.

Recent progress in the chemistry of β-aminoketones.

The β-aminoketone moiety has been found to be the basic skeleton of several drugs such as the amine salts "tolperisone (vasodilation)" and "oxyfedrine (therapeutic coronary disease)", and fluoroaryl derivatives such as "sitagliptin (antidiabetic)". The objective of this review is to summarize and highlight the chemistry of compounds reported with a β-aminoketone core in the last five years regarding their synthetic strategies, chemical reactivity, and mechanistic synthetic pathways. In the different sections, we categorize the synthesis of β-aminoketones by Mannich reactions catalytic, non-catalytic, and one-pot procedures.

Recent advancements in the multicomponent synthesis of heterocycles integrated with a pyrano[2,3-]pyrimidine core.

Heterocyclic compounds incorporated with a pyranopyrimidine skeleton have received substantial consideration owing to their privileged, and intelligible biodiversity. Accordingly, this review highlights the multicomponent synthetic routes adopted to prepare heterocyclic compounds incorporated with the pyrano[2,3-]pyrimidine skeleton in the preceding two years. The different sections comprise the synthesis of bicyclic, tricyclic, polycyclic, and spirocyclic systems along with the estimation of the probable mechanistic routes for the reaction pathways.

Advances in the chemical and biological diversity of heterocyclic systems incorporating pyrimido[1,6-]pyrimidine and pyrimido[1,6-]pyrimidine scaffolds.

Heterocycles incorporating a pyrimidopyrimidine scaffold have aroused great interest from researchers in the field of medical chemistry because of their privileged biological activities; they are used as anti-bacterial, antiviral, anti-tumor, anti-allergic, antihypertensive, anticancer, and hepatoprotective agents. Therefore, the present study aims to investigate the chemistry of heterocycles incorporating pyrimido[1,6-]pyrimidine and pyrimido[1,6-]pyrimidine skeletons and their biological characteristics. The main sections discuss (1) the synthetic routes to obtain substituted pyrimidopyrimidines, pyrimido[1,6-]pyrimidin-diones, pyrimidoquinazolines, tricyclic, tetracyclic, and binary systems; (2) the reactivity of the substituents attached to the pyrimidopyrimidine skeleton, including thione and amide groups, nucleophilic substitutions, condensations, ring transformations, and coordination chemistry; (3) compounds of this class of heterocycles containing a significant characteristic scaffold and possessing a wide range of biological characteristics.

Bicyclic 6 + 6 systems: the chemistry of pyrimido[4,5-]pyrimidines and pyrimido[5,4-]pyrimidines.

The present study provides an overview of the chemistry and biological significance of pyrimido[4,5-]pyrimidine and pyrimido[5,4-]pyrimidine analogs as types of bicyclic [6 + 6] systems. The main sections include: (1) synthesis methods; (2) the reactivities of the substituents linked to the ring carbon and nitrogen atoms; and (3) biological applications. A discussion demonstrating the proposed mechanisms of unexpected synthetic routes is intended.