Ng JH, Tiekink ERT, Dolzhenko AV. Three-component microwave-assisted synthesis of 3,5-disubstituted pyrazolo[3,4-
d]pyrimidin-4-ones.
RSC Adv 2022;
12:8323-8332. [PMID:
35424837 PMCID:
PMC8984946 DOI:
10.1039/d2ra00980c]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 03/09/2022] [Indexed: 11/21/2022] Open
Abstract
A practical three-component method for the synthesis of pyrazolo[3,4-d]pyrimidin-4-ones was developed. The reaction was performed in a one-pot manner under controlled microwave irradiation using easily accessible methyl 5-aminopyrazole-4-carboxylates, trimethyl orthoformate, and primary amines. Under the optimized conditions, challenging substrates, such as N-1 unsubstituted 5-aminopyrazole-4-carboxylates with another substituted amino group in position 3, reacted selectively affording 5-substituted 3-arylamino-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-ones. The reaction tolerated a range of primary amines, including anilines. The advantages of the developed protocol include short reaction time, pot- and step-economy, and convenient chromatography-free product isolation. The structural features of representative products were explored by X-ray crystallography.
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