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Synthesis of pyrrolo[3,2-a]phenazines from 5-nitroindoles and anilines.

Wróbel Z, Więcław M, Bujok R, Wojciechowski K - Monatsh. Chem. (2013)

Bottom Line: Anilines react with 5-nitroindoles in the presence of t-BuOK in N,N-dimethylformamide (DMF) to form 5-nitroso-4-arylaminoindoles that in turn when treated with N,O-bis(trimethylsilyl)acetamide cyclize to pyrrolo[3,2-a]phenazines.In an alternative approach pyrrolo[3,2-a]phenazines are formed from aminoindoles and nitroarenes.

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Affiliation: Institute of Organic Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, P.O. Box 58, 01-224 Warsaw, Poland.

ABSTRACT

Abstract: Anilines react with 5-nitroindoles in the presence of t-BuOK in N,N-dimethylformamide (DMF) to form 5-nitroso-4-arylaminoindoles that in turn when treated with N,O-bis(trimethylsilyl)acetamide cyclize to pyrrolo[3,2-a]phenazines. In an alternative approach pyrrolo[3,2-a]phenazines are formed from aminoindoles and nitroarenes.

No MeSH data available.


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Mentions: Alternatively, the pyrrolo[2,3-a]phenazines can be obtained from aminoindoles and nitroarenes (Scheme 4). Thus, when we reacted 4-aminoindole 6a with 4-nitroanisole (5) under standard conditions (t-BuOK/DMF, −50 °C) the expected nitrosoaniline 7a was formed. Since the amine 7a proved unstable, it was without purification subjected to reaction with BSA and cyclized to 9-methoxypyrrolo[3,2-a]phenazine 4g that was isolated in 90 % yield. Similarly 5-aminoindole 6b and 4-nitroanisole formed the relatively stable nitroso derivative 7b that was isolated in 40 % yield. Treatment of the compound 7b with BSA led to isomeric 8-methoxypyrrolo[3,2-a]phenazine 4h in 64 % yield.


Synthesis of pyrrolo[3,2-a]phenazines from 5-nitroindoles and anilines.

Wróbel Z, Więcław M, Bujok R, Wojciechowski K - Monatsh. Chem. (2013)

© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4495017&req=5

Mentions: Alternatively, the pyrrolo[2,3-a]phenazines can be obtained from aminoindoles and nitroarenes (Scheme 4). Thus, when we reacted 4-aminoindole 6a with 4-nitroanisole (5) under standard conditions (t-BuOK/DMF, −50 °C) the expected nitrosoaniline 7a was formed. Since the amine 7a proved unstable, it was without purification subjected to reaction with BSA and cyclized to 9-methoxypyrrolo[3,2-a]phenazine 4g that was isolated in 90 % yield. Similarly 5-aminoindole 6b and 4-nitroanisole formed the relatively stable nitroso derivative 7b that was isolated in 40 % yield. Treatment of the compound 7b with BSA led to isomeric 8-methoxypyrrolo[3,2-a]phenazine 4h in 64 % yield.

Bottom Line: Anilines react with 5-nitroindoles in the presence of t-BuOK in N,N-dimethylformamide (DMF) to form 5-nitroso-4-arylaminoindoles that in turn when treated with N,O-bis(trimethylsilyl)acetamide cyclize to pyrrolo[3,2-a]phenazines.In an alternative approach pyrrolo[3,2-a]phenazines are formed from aminoindoles and nitroarenes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, P.O. Box 58, 01-224 Warsaw, Poland.

ABSTRACT

Abstract: Anilines react with 5-nitroindoles in the presence of t-BuOK in N,N-dimethylformamide (DMF) to form 5-nitroso-4-arylaminoindoles that in turn when treated with N,O-bis(trimethylsilyl)acetamide cyclize to pyrrolo[3,2-a]phenazines. In an alternative approach pyrrolo[3,2-a]phenazines are formed from aminoindoles and nitroarenes.

No MeSH data available.