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A modified bischler‐napieralski reaction. Synthesis of 2,3,4,9‐ tetrahydro‐1 H ‐pyrido[3,4‐ B ]indole derivatives and their base‐catalyzed transformation to N ‐acetyl‐ N ‐[2‐[1 ‐acetyl‐2‐[1 ‐(acetyloxy)‐1‐propenyl]‐ 1 H ‐indol‐3‐yl]ethyl]acetamides
Author(s) -
Bobowski George
Publication year - 1983
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.5570200138
Subject(s) - chemistry , acetic anhydride , triethylamine , catalysis , medicinal chemistry , isocyanate , acetylation , alkyl , pyridine , organic chemistry , enol , indole test , biochemistry , polyurethane , gene
The treatment of N ‐[2‐(1 H ‐indol‐3‐yl)ethyl]alkanamide, 1 (1), with phosphorus oxychloride under controlled conditions gave l‐alkyl‐2,3,4,9‐tetrahydro‐1 H ‐pyrido[3,4‐ b ]indol‐1‐ol, 2 . The reaction of 2 with acetic anhydride or with methyl isocyanate at room temperature resulted in the formation of amido carbinol 3 and urea carbinol 7, respectively. The former was transformed into amido ester 4 by boiling acetic anhydride. When the reaction of 3 with acetic anhydride was carried out in the presence of excess triethylamine at 105°, C‐N bond cleavage of the tetrahydropyridine ring took place with concurrent bis( N ‐acetylation) to give the enol ester derivative 5 . The structures of all compounds are consistent with chemical and spectral evidence.