73910-75-5

Upstream product

• 1576-35-8 toluene-4-sulfonic acid hydrazide 
• 4545-18-0 N'-cyclohexylidene-4-methylbenzene-1-sulfonohydrazide 
• 141091-37-4 2-(cyclohex-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane 
• 89490-05-1 cyclohex-1-enylboronic acid 
• 536-89-0 m-tolylhydrazine 
• 1093413-52-5 C₁₆H₁₅NO₄ 
• 82463-59-0 cyclohexane-1,2-dione-mono-m-tolylhydrazone 

Downstream Products

• 3652-91-3 2-methyl-9H-carbazole 
• 141-97-9 ethyl acetoacetate 
• 836612-59-0 2-acetyl-7-methyl-1-hydroxycarbazole 
• 1342300-98-4 2-methyl-9-nitro-7-phenyl-6,13-dihydro-5H-indolo[3,2-c]acridine 
• 1231726-31-0 9-chloro-6,13-dihydro-2-methyl-7-phenyl-5H-indolo[3,2-c]acridine 
• 73910-77-7 1-hydroxy-7-methylcarbazole 

Relevant academic research and scientific papers

Copper-catalyzed tri- or tetrafunctionalization of alkenylboronic acids to prepare tetrahydrocarbazol-1-ones and indolo[2,3-a]carbazoles

We describe a cascade strategy for tri- or tetrafunctionalization of alkenylboronic acids to prepare diverse tetrahydrocarbazol-1-ones and indolo[2,3-a]carbazoles in good yields withN-hydroxybenzotriazin-4-one (HOOBT) and arylhydrazines as oxygen and nitrogen sources, respectively. Mechanistic studies reveal that the domino reaction undergoes the copper-catalyzed Chan-Lam reaction, [2,3]-rearrangement, nucleophilic substitution, oxidation and sequential [3,3]-rearrangement over five steps in a one-pot reaction. The reaction shows a broad substrate scope and tolerates a wide range of functional groups. More importantly, the reaction is easily performed at gram scales and the product is purified by simple extraction, washing, and recrystallization without flash column chromatography. The present protocol features easily available starting materials, high site-marked functionalization, five-step cascade in one pot, multiple C-C/C-O/C-N bond formation, and diversity of indole motifs.

Reactions of methyl 2-(1-oxo-2,3,4,9-tetrahydro-1H-carbazol-2-yl) oxoacetates. Synthesis of methyl isoxazolo[5,4-a]carbazole-3-carboxylates

The reaction of methyl 2-(1-oxo-2,3,4,9-tetrahydro-1H-carbazol-2-yl) oxoacetates (1a-e) with hydroxylamine hydrochloride in alcoholic KOH afforded 1-hydroxyimino-2,3,4,9-tetrahydro-1H-carbazoles (2a-e), and in acetic acid methyl isoxazolo[5,4-a]carbazole-3-carboxylates (3a-e). Ketoesters 1a-e with urea and thiourea under acidic conditions yielded a mixture of the respective 1-hydroxycarbazoles (6a-e) and 2,3,4,9-tetrahydro-1H-carbazol-1-ones (7a-e), but under basic conditions the respective 1-carbimido-and 1-thiocarbimido-2,3,4,9- tetrahydro-1H-carbazoles (8a-e and 9a-e) were formed. Plausible mechanisms are proposed.

Synthesis of 2-hydroxypyrido[2,3-a]carbazoles and 2-hydroxypyrimido[4,5- a]carbazoles from 1-hydroxycarbazoles

Gattermann reaction on substituted 1-hydroxycarbazoles (4a-d) afforded substituted 1-hydroxycarbazole-2-carbaldehydes (5a-d) from which synthesis of either 2-hydroxypyrido[2,3-a]carbazoles (7a-d) via Perkin reaction or 2- hydroxypyrimido[4,5-a]carbazoles (8a-d) via condensation with urea could be achieved.