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Synthesis of 4‐hydrazino‐5 H ‐pyrimido[5,4‐ b ]indole and related compounds
Author(s) -
Monge A.,
Palop J. A.,
Goñi T.,
MartinezCrespo F.,
Recalde I.,
FernandezAlvarez E.
Publication year - 1986
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570230302
Subject(s) - chemistry , indole test , formamide , morpholine , hydrazine (antidepressant) , piperidine , formic acid , medicinal chemistry , stereochemistry , organic chemistry , chromatography
This paper describes the synthesis of two 4‐amino‐5 H ‐pyrimido[5,4‐ b ]indoles 5 , 4‐hydrazino‐5 H ‐pyrimido[5,4‐ b ]indole 6 , two 1,2,4‐triazolo[4,3‐ c ]pyrimido[5,4‐ b ]indoles 8 , and tetrazolo[4,5‐ c ]pyrimido[5,4‐ b ]indole 10 . Starting with ethyl 3‐aminoindole‐2‐carboxylate 1 , 5 H ‐pyrimido[5,4‐ b ]indol‐4‐one 2 was obtained (80%) by condensing with formamide. Reactions of 2 with phosphorus oxychloride and phosphorus pentasulfide gave respectively, 4‐chloro‐5 H ‐pyrimido[5,4‐ b ]indole 3 (70%) and 5 H ‐pyrimido[5,4‐ b ]indole‐4‐thione 4 (80%). Compound 3 reacted with amines (morpholine, piperidine) to give the respective 4‐amino‐5 H ‐pyrimido[5,4‐ b ]‐indoles 5 , and compound 4 reacted with hydrazine to give 4‐hydrazino‐5 H ‐pyrimido[5,4‐ b ]indole 6 (80%). Two hydrazones of 6 (benzylidene, isopropylidene) 7 were also prepared (90%). Compound 6 reacted with formic and acetic acids to give (65–75%) the respective 1,2,4‐triazolo[4,3‐ c ]pyrimido[5,4‐ b ]indoles 8 and with nitrous acid to give tetrazolo[4,5‐ c ]pyrimido[5,4‐ b ]indole 9 (85%). All the new compounds 2 to 9 were characterized by elemental analysis and spectral data (ir, nmr).