Synlett 2018; 29(08): 1037-1042
DOI: 10.1055/s-0037-1609321
letter
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Dihydrospiro Furo[2,3-c]pyrazoles Promoted by Hypervalent Iodine in Water

Ashok Kale
a   Division of Crop Protection Chemicals, CSIR – Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India, Email: krishnu@iict.res.in
b   AcSIR – Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India
,
Nagaraju Medishetti
a   Division of Crop Protection Chemicals, CSIR – Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India, Email: krishnu@iict.res.in
,
Chiranjeevi Bingi
a   Division of Crop Protection Chemicals, CSIR – Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India, Email: krishnu@iict.res.in
,
Krishnaiah Atmakur*
a   Division of Crop Protection Chemicals, CSIR – Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India, Email: krishnu@iict.res.in
b   AcSIR – Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India
› Author Affiliations
We are grateful to SERB-DST, New Delhi for financial support (grant no. EEQ/20l6/000066). Ashok is thankful to UGC, New Delhi for SRF.
Further Information

Publication History

Received: 07 December 2017

Accepted after revision: 29 January 2018

Publication Date:
26 February 2018 (online)


Abstract

A simple, green protocol has been accomplished for the synthesis of dihydrospirofuro[2,3-c]pyrazoles in aqueous medium involving pyrazolone and aldehydes in a one-pot reaction promoted by bis(acetoxy)iodobenzene (BAIB) at ambient temperature. The protocol presented herein describes a new transformation where two molecules of pyrazolone react with an aldehyde in a Knoevenagel condensation followed by a Michael addition, and the resulting dienol was rearranged to the title compound. High compatibility, easy work-up, and excellent yields are the advantages of this protocol.

Supporting Information