Syntheses and medicinal chemistry of spiro heterocyclic steroids

There is compelling evidence that incorporating a heterocyclic moiety into a steroid can alter its pharmacological and pharmacokinetic properties, driving intense interest in the synthesis of such hybrids among research groups. In this review, we present an overview of recent synthetic methodologies, spanning the period from 2000 to 2023, for the preparation of spiro heterocyclic steroids. The compounds surveyed encompass four-, five-, six-, and seven-membered heterocycles appended to various positions of steroidal backbones, with spirocycles containing oxygen, nitrogen, and sulfur atoms being predominant. The outlined synthetic procedures emphasize the pivotal steps for constructing the heterocycles, often accompanied by a detailed account of the overall synthesis pathway. The review encompasses innovative compounds, including bis-steroids linked by a spiro heterocycle and steroids conjugated to heterocyclic moieties containing three or more (hetero)cycles. Moreover, many compounds are accompanied by data on their biological activities, such as antiproliferative, antimalarial, antimicrobial, antifungal, steroid antagonist, and enzyme inhibition, among others, aimed at furnishing pertinent insights for the future design of more potent and selective drugs.