A series of novel spiro-piperidinyl pyrazolones were synthesized starting from the commercially available ethyl
nipecotate. The Boc protected ethyl nipecotate was reacted with 5-bromo-2-furaldehyde in the presence of LDA to afford
the β -hydroxy ester which was converted to the β -keto ester by oxidation using manganese dioxide. Furthermore, β-keto
ester was treated with hydrazine to form the spiro-piperidinyl pyrazolone scaffold. The phenyl/heteroaryl substituted (6ai)
and hetero/arylethynyl substituted (7a-d) spiro pyrazolone were prepared by Suzuki and Sonogashira coupling followed
by deprotection of the protecting group. All the synthesized compounds were evaluated for their invitro antiviral activity
against BPXV on Vero cells. Compound 6c, 6d and 7c in the series showed potent antiviral activity.
Keywords: Spiro piperidines, pyrazolones, aryl furan, suzuki coupling, sonogashira coupling, antiviral activity.
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