Synthesis of Methyl 5- and 6-Nitroindole-2-carboxylates by Nitration of Indoline-2-carboxylic Acid

Abstract

Indoline-2-carboxylic acid was transformed into 6-nitroindoline-2-carboxylic acid, the methyl ester of which was easily dehydrogenated by DDQ to methyl 6-nitroindole-2-carboxylate (total yield: 67%). Methyl 5-nitroindole-2-carboxylate was obtained by the nitration of methyl 1-acetylindoline-2-carboxylate acid followed by dehydrogenation with MnO₂ in toluene in 40% total yield.

methyl 5- and 6-nitroindole-2-carboxylate - indoline-indole method - indoles

References

<A NAME="RZ11901SS-1">1</A> Parmerter SM. Cook AG. Dixon WB. J. Am. Chem. Soc.  1958,  80:  4621 

<A NAME="RZ11901SS-2">2</A> Cavallini G. Ravenna F. Farmaco Ed. Sci.  1958,  1:  105 ; Chem. Abstr. 1958, 52, 20126

<A NAME="RZ11901SS-3">3</A> Kost AN. Sagittulin RS. Gorbunov VI. Barinova GI. Khim. Farm. Zh.  1967,  3:  14 ; Chem. Abstr. 1967, 67, 67532

<A NAME="RZ11901SS-4">4</A> Boger DL. Yun W. Han N. Johnson DS. Bioorg. Med. Chem.  1995,  3:  611 

<A NAME="RZ11901SS-5">5</A> Preobrazhenskaya MN. Russ. Chem. Rev.  1967,  36:  753 

<A NAME="RZ11901SS-6">6</A> Fatiadi AJ. Synthesis  1976,  133