%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