19283-46-6

Upstream product

• 6134-75-4 5-methyl-2-oxocyclohexanecarboxylic acid ethyl ester 
• 62-53-3 aniline 
• 589-92-4 1-methylcyclohexan-4-one 
• 2684-02-8 benzenediazonium 
• 62334-20-7 2-hydroxymethylene-4-methylcyclohexanone 

Downstream Products

• 65266-48-0 N-(2,2-diethoxyethyl)-N-(1,4-dimethyl-9H-carbazol-3-ylmethyl)-4-methylbenzenesulfonamide 
• 129868-41-3 9-benzyl-3-((N-(2,2-diethoxyethyl)-N-tosylamino)methyl)-1,4-dimethylcarbazole 
• 129868-40-2 9-benzyl-3-((2,2-diethoxyethyl)iminomethyl)-1,4-dimethylcarbazole 
• 74606-36-3 6-benzyl-5,11-dimethyl-6H-pyrido[4,3-b]carbazole 
• 129868-48-0 9-benzyl-5,8-dimethylcarbazole-3-carboxaldehyde 
• 129868-46-8 9-benzyl-1,2,3,4-tetrahydro-4-methylcarbazole-1-carbaldehyde 
• 87167-62-2 9-benzyl-1,4-dimethyl-9H-carbazole-3-carbaldehyde 
• 120090-53-1 9-benzyl-1,4-dimethyl-9H-carbazole 
• 519-23-3 ellipticine 
• 17017-64-0 9-benzyl-4-methyl-2,3,4,9-tetrahydro-1H-carbazole 

Relevant academic research and scientific papers

Total Synthesis of Olivacine and Ellipticine via a Lactone Ring-Opening and Aromatization Cascade

Effective preparation of olivacine and ellipticine via late-stage D-ring cyclization is described. Key features of the synthetic routes include trifluoroacetic acid-mediated formation of a lactone that is fused to a tetrahydrocarbazole derivative and its one-pot two-step ring opening and aromatization mediated by para-toluenesulfonic acid and palladium on carbon, respectively.

Synthesis of 4-methyl-1-oxo-tetrahydrocarbazoles

Condensation of the diazotised aniline derivatives (1a-d) with 2-hydroxymethylene-4-methylcyclohexanone (2) affords the respective monoarylhydrazones (3a-d) which on cyclisation with a mixture of acetic acid and hydrochloric acid furnish the title compounds, 4-methyl-1-oxo-1,2,3,4-tetrahydrocarbazoles (4a-d).

Synthetic Studies of Indoles and Related Compounds, Part 221. The Vilsmeier-Haack Reaction of N-Benzyl-1,2,3,4-tetrahydrocarbazoles and its Synthetic Application to Olivacine and Ellipticine2

Vilsmeier-Haack reaction of 9-benzyl-1,2,3,4-tetrahydrocarbazole (18a) at 120 deg C gave 9-benzyl-1-methylcarbazole-3-carbaldehyde (19a) and 9-benzyl-1-(N,N-(dimethylamino)methyl)carbazole-3-carbaldehyde (22a) in moderate yields, whereas, the same reaction at 0 deg C gave 9-benzyl-1,2,3,4-tetrahydrocarbazole-1-carbaldehyde (20a) in very good yield.The aldehyde (20a) was converted into 9-benzyl-1-methylcarbazole (21a) by another Vilsmeier-Haack reaction.This carbazole (21a) unexpectedly underwent non-regioselective formylation under similar reaction conditions to give a mixture of compound (19a) and 9-benzyl-8-methylcarbazole-3-carbaldehyde (23a).On the basis of the above results, a mechanism of the formation of the aromatic aldehyde (19a) was proposed, which involves 1,5-sigmatropic rearrangement of an N-methylidene dimethylammonium cation from the 4a-position to the 3-position as a key step.Vilsmeier-Haack reaction of 9-benzyl-1,2,3,4-tetrahydro-4-methylcarbazole (18b) at 100 deg C also gave 9-benzyl-1,4-dimethylcarbazole-3-carbaldehyde (19b) in moderate yield.The total syntheses of two antitumor alkaloids, olivacine (10) and ellipticine (11), were achieved by utilizing compounds (19a) and (19b) as key intermediates.