ИСТИНА

Piperidinones are structural motif of many alkaloids, peptidomimetics, small biologically active molecules etc. as well as key intermediates in syntheses of pharmaceutically relevant compounds. We have elaborated a new concise and efficient method of synthesis of piperidine-2,4-diones and 2-iminopiperidine-4-(thi)ones starting from easily available gomoallylamines. The synthetic sequence for piperidinones consists of three steps: a) acylation of amino group either with Boc2O or an isocyanate; b) cyclobromocarbamation with NBS; c) enolate-type rearrangement in the presence of t-BuOK.We proofed that these transformations involve the formation of enolate-isocyanate and (thio)enolate-carbodiimide as intermediates. In case of formation of piperidine-2,4-diones it was conducted kinetical analysis which confirmed the first-order kinetic and highly reactive nature of the intermediate. The present approach can be very useful and advantageous especially for the synthesis of complex molecules containing fragment of piperidinone since the introduction of allyl group is simple and well elaborated.