Synthesis of methoxy-2-quinolones via pummerer-type cyclization of N-aryl-N-methyl-3-(phenylsulfinyl)propionamides.
The thionium ions 10 generated by Pummerer reaction of N-aryl-N-methyl-3-(phenylsulfinyl)propionamides 4 caused not only an electrophilic cyclization reaction producing 2-quinolones 8, but also the formation of the vinyl sulfides 5 and 6 in favor of the latter reaction. On the other hand, the treatment of the vinyl sulfides 5 and 6 with p-toluenesulfonic acid induced cyclization to afford the 2-quinolones 8 in excellent to moderate yields, depending on the electronic properties of the aromatic ring, thus providing a convenient method for the synthesis of methoxy-2-quinolones.
Toda
J
J
Showa Pharmaceutical University, Machida, Tokyo, Japan.
Sakagami
M
M
Goan
Y
Y
Simakata
M
M
Saitoh
T
T
Horiguchi
Y
Y
Sano
T
T
D000089:Acetic Anhydrides; D000577:Amides / Q000737:chemistry*; D003500:Cyclization; D005463:Fluoroacetates; D015363:Quinolones / Q000138:chemical synthesis* / Q000737:chemistry; D013454:Sulfoxides / Q000737:chemistry*; D014269:Trifluoroacetic Acid / Q000737:chemistry
D000089:Acetic Anhydrides; D000577:Amides; D005463:Fluoroacetates; D015363:Quinolones; D013454:Sulfoxides; C017958:trifluoroacetic anhydride; D014269:Trifluoroacetic Acid