Synthesis of novel 16-spiro steroids: Spiro-7′-(aryl)tetrahydro-1H-pyrrolo[1,2-c][1,3]thiazolo-trans-androsterone hybrid heterocycles

The 1,3-dipolar cycloaddition of azomethine ylide derived in situ from the reaction of acenaphthylene-1,2-dione and 1,3-thiazolane-4-carboxylic acid to various exocyclic dipolarophiles synthesized from trans-androsterone and trans-dehydroandrosterone afforded a library of novel spiro[5′.2″]acenaphthylene-1″-one-spiro[16.6′]-(7′-aryl)-tetrahydro-1H-pyrrolo [1,2-c][1,3]thiazolo-trans-androsterone/dehydroandrosterone hybrid heterocycles respectively. These reactions proceeded stereo-specifically affording a single isomer of the 16-spiro steroids in excellent yields.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► 1,3-Dipolar cycloaddition of azomethine ylide to steroidal dipolarophiles. ► Stereospecific synthesis of 22 novel 16-spiro androsterones/dehydroandrosterones. ► The azomethine ylide cycloaddition proceeds regioselectively. ► Structure of these 16-spirosteroids elucidated with 1 and 2D NMR spectroscopy. ► The absolute configuration determined by single crystal X-ray studies.