Synthesis of Substituted 5-(3-Hydroxypropyl)pyrrolidin-2-ones and Pyrrolizidinones from Nitroethane via C3 Functionalized 5,6-Dihydro-4H-1,2-oxazines: A Novel Approach to Some Analogues of the Antidepressant Rolipram

Abstract

Easily accessible [(5,6-dihydro-4H-1,2-oxazin-3-yl)methyl]malonates­ 1 were converted into substituted 5-(3-hydroxypropyl)pyrrolidin-2-ones 2 and pyrrolizidinones 3, which are versatile products and intermediates for organic and bioorganic chemistry. The synthetic sequence suggested includes stereoselective two-step reduction of an oximino fragment, followed by intramolecular cyclization involving one of the CO₂Me groups and decarboxylation in the last stage. The efficiency of this strategy was demonstrated by the stereoselective synthesis of pyrrolizidinone rac-4, a highly efficient analogue of antidepressant Rolipram, from nitroethane.

5,6-dihydro-4H-1,2-oxazines - reduction - pyrrolidones - pyrrolizidinones - Rolipram

References

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