4-[5-(3,5-Difluorophenyl)furan-2-yl]-2,3,7-triazaspiro[4.5]dec-3-en-1-one Hydrochloride

Rajagopalan Srinivasan,Badiadka Narayana,Balladka Kunhanna Sarojini,Seranthimata Samshuddin

doi:10.3390/m773

Rajagopalan Srinivasan, Badiadka Narayana + Show 2 more

Open Access

https://doi.org/10.3390/m773

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Abstract

A novel route for the synthesis of new spirocyclic derivative is developed. The present work involves the synthesis of title compound 3 by Suzuki coupling of 3,5-difluorophenyl boronic acid with tert-butyl 1-(5-bromofuran-2-yl)-4-oxo-2,3,7-triazaspiro[4.5]dec-1-ene-7-carboxylate (2), which in turn prepared from the ethyl nipecotate (1). Newly prepared spirocyclic derivative (3) is characterized by IR, NMR and mass spectral data.

Highlights

The spiro framework is an important subunit in a vast number of natural products such as alkaloid:(−)-sibirine, fused tetracyclic lycopodium alkaloid: nankakurine-A, several spongistatins: β-vetivone, acorenone B, fredericamycin and Shizuca-acordienol [1,2]
The title compound, 4-[5-(3,5-diflurophenyl)furan-2-yl]-2,3,7-triazaspiro[4.5]dec-3-en-1-one hydrochloride (3), was prepared by the PdCl2 catalyzed Suzuki coupling of tert-butyl 1-(5bromofuran-2-yl)-4-oxo-2,3,7-triazaspiro[4.5]dec-1-ene-7-carboxylate (2) with 3,5-difluorophenyl boronic acid followed by deprotection of Boc group (Scheme 1)
A singlet observed at δ 12.18 ppm was due to the proton of piperidine NH. Another singlet observed at δ 9.70 ppm was due to the proton of pyrazolone NH

Summary

Introduction

The spiro framework is an important subunit in a vast number of natural products such as alkaloid:(−)-sibirine, fused tetracyclic lycopodium alkaloid: nankakurine-A, several spongistatins: β-vetivone, acorenone B, fredericamycin and Shizuca-acordienol [1,2]. For the synthesis of spiro compounds [9,10,11]. The title compound, 4-[5-(3,5-diflurophenyl)furan-2-yl]-2,3,7-triazaspiro[4.5]dec-3-en-1-one hydrochloride (3), was prepared by the PdCl2 (dppf) catalyzed Suzuki coupling of tert-butyl 1-(5bromofuran-2-yl)-4-oxo-2,3,7-triazaspiro[4.5]dec-1-ene-7-carboxylate (2) with 3,5-difluorophenyl boronic acid followed by deprotection of Boc group (Scheme 1). The intermediate 2, a bromo substituted derivative of tert-butyl 1-(furan-2-yl)-4-oxo-2,3,7-triazaspiro[4.5]dec-1-ene-7-carboxylate, was prepared by using 5-bromo-2-furaldehyde as described in our earlier work [12].

Results

Conclusion