Synthesis of Novel Spiro[pyrazole-pyrrolizin] Derivatives via 1,3-Dipolar Cycloaddition of Nitrilimine

Abstract

The 1,3-dipolar cycloaddition of nitrilimine generated in situ from N'-phenylbenzohydrazonoyl chloride and triethylamine to 2-arylmethylidene-2,3-dihydro-1H-pyrrolizin-1-ones afforded novel 4-aryl-2,5-diphenyl-2,4-dihydrospiro-[pyrazole-3,2'-pyrrolizin]-1'(3'H)-ones in moderate yields. The structures of all products were characterized thoroughly by NMR, IR, mass spectra and elemental analysis.

Synthesis of Chromeno[3,4-c]Pyrazole from N-Tosylhydrazones and 3-Nitro-2-Phenyl-2H-Chromene

“…[13][14][15] They can generate diazo intermediates in situ in the presence of bases. In continuation of our work [16][17][18][19] on the synthesis of pyrazole derivatives, here we report the synthesis of chromeno [3,4-c]pyrazole derivatives by reaction of 3-nitro-2-phenyl-2H-chromene and N-tosylhydrazones under basic conditions (Scheme 2).…”