An environmentally benign spirocyclization is described for the synthesis of 4-spiropiperidines from 2-aminocarbohy-drazides in water at room temperature without any catalyst. The condensation of carbocyclic 2-aminocarbohydrazides with A'-benzylpiperidinone (2) led to 3'-aminospiropiperidine-quinazolinones (3a-3d). Anthranilic hydrazide 4 gave 2-amino-A''-(l-benzylpiperidin-4-ylidene) benzohydrazide (7), while glycine hydrazide (8) reacted with 2 moles of 2 to afford l-benzylpiperidin-4-ylidenamino-l,4,8-triazaspiro[4.5]decane (9). All products precipitated from the reaction mixture and were obtained in excellent yields. No further work-up or purification was necessary.
|Number of pages||6|
|Journal||Acta Chimica Slovenica|
|Publication status||Published - Sep 30 2009|
- Aqueous media
- Green synthesis
- Methylene-bridged quinazolines
ASJC Scopus subject areas