%0 Generic
%A Charris-Molina, Andrés
%A Castillo, Juan-Carlos
%A Macías, Mario
%A Portilla, Jaime
%D 2017
%T One-Step Synthesis of Fully Functionalized Pyrazolo[3,4‑b]pyridines via Isobenzofuranone Ring Opening
%U https://acs.figshare.com/articles/dataset/One-Step_Synthesis_of_Fully_Functionalized_Pyrazolo_3_4_i_b_i_pyridines_via_Isobenzofuranone_Ring_Opening/5616520
%R 10.1021/acs.joc.7b02471.s002
%2 https://acs.figshare.com/ndownloader/files/9778822
%K substrate 2
%K 5- aminopyrazoles 1
%K isobenzofuranone ring opening
%K NMR
%X A novel series of fully substituted
pyrazolo[3,4-b]pyridines 4 has been
prepared in a regioselective manner
by the microwave-assisted reaction between N-substituted
5-aminopyrazoles 1 and 3-(3-oxo-2-benzofuran-1(3H)-ylidene)pentane-2,4-dione (2). This is the
second reported example of a cyclocondensation reaction using substrate 2 as a 1,3-bis-electrophilic reagent. Remarkably, this synthesis
offers functionalized products with acetyl and carboxyl groups in
one step, in good yields, and with short reaction times. Additionally,
the cyclization intermediate 3 was isolated, allowing
us to postulate a mechanism for this reaction, which is initiated
via isobenzofuranone ring opening of 2 in a Michael-type
reaction. The structures of the products and regioselectivity of the
reactions were determined on the basis of NMR measurements and X-ray
diffraction. For this new reaction using substrate 2,
the optimal reaction conditions and its scope were investigated.
%I ACS Publications