Synthesis 2019; 51(19): 3617-3624
DOI: 10.1055/s-0039-1690104
paper
© Georg Thieme Verlag Stuttgart · New York

1-Nicotinoylbenzotriazole: A Convenient Tool for Site-Selective Protection of 5,7-Dihydroxycoumarins

Ramil F. Fatykhov
a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   eMail: i.a.khalymbadzha@urfu.ru
,
a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   eMail: i.a.khalymbadzha@urfu.ru
b   Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Kovalevskoy 22, 620219 Ekaterinburg, Russian Federation
,
a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   eMail: i.a.khalymbadzha@urfu.ru
b   Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Kovalevskoy 22, 620219 Ekaterinburg, Russian Federation
,
Valery N. Charushin
a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   eMail: i.a.khalymbadzha@urfu.ru
b   Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Kovalevskoy 22, 620219 Ekaterinburg, Russian Federation
,
Anna K. Inyutina
a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   eMail: i.a.khalymbadzha@urfu.ru
,
Pavel A. Slepukhin
b   Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Kovalevskoy 22, 620219 Ekaterinburg, Russian Federation
,
Victor G. Kartsev
c   InterBioScreen Ltd., Institutsky Prospect 7a, 142432 Chernogolovka, Russian Federation
› Institutsangaben
We are grateful to the Russian Science Foundation (project #18-73-00163, synthesis of compounds 611) and the Ministry of Education and Science of the Russian Federation (project 4.6351.2017/8.9, synthesis of compounds 12 and 13).
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Publikationsverlauf

Received: 13. März 2019

Accepted after revision: 07. Juni 2019

Publikationsdatum:
26. Juni 2019 (online)


Abstract

1-Nicotinoylbenzotriazole (NicBt) was uncovered as an efficient protecting agent for the site-selective acylation of resorcinol-type phenolic groups with almost equal reactivity. The use of NicBt allows selective protection of the 7-OH group in 5,7-dihydroxycoumarins in one simple scalable step, while combination of the nicotinoylation with tosylation–denicotinoylation or silylation–denicotinoylation yields 5-OH-protected 5,7-dihydroxycoumarins. Furthermore, nicotinoylated 5,7-dihydroxycoumarins proved useful in a gram-scale three-step preparation of a 2,2-dimethylpyrano[2,3-f]coumarin, a key intermediate for the synthesis of calanolide A, an HIV reverse transcriptase and Mycobacterium tuberculosis inhibitor, and its active analogues.

Supporting Information