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Note | Regular issue | Vol 53, No. 2, 2000, pp.409-417
Published online, 1st January, 1970
DOI: 10.3987/COM-99-8753
Synthesis of Pyridopyranoquinolines by the Skraup Reaction of Amino-5H-benzopyrano[2,3-b]pyridin-5-ones

Hidetoshi Fujiwara* and Kouki Kitagawa

*Niigata College of Pharmacy, 5-13-2 Kamishin’ei-cho, Niigata 950-2081, Japan

Abstract

7-, 8- and 9-amino-5H-[1]benzopyrano[2,3-b]pyridin-5-ones were synthesized. Skraup reaction of 6-amino-, 7-amino-, 8-amino- and 9-amino-5H-[1]benzopyrano[2,3-b]pyridin-5-ones in the presence of glycerol, fuming sulfuric acid, nitrobenzene, iron(II) sulfate and boric acid gave 12H-pyrido[3’,2’:5,6]pyrano[2,3-h]quinolin-12-one, 12H-pyrido[3’,2’:5,6]pyrano[3,2-f]quinolin-12-one, 7H-pyrido[3’,2’:5,6]pyrano[2,3-f]quinolin-7-one and 7H-pyrido[3’,2’:5,6]pyrano[3,2-h]quinolin-7-one, respectively.