Microwave-assisted synthesis of tetrahydroindoles

Hexafluoroisopropanol: a powerful solvent for the hydrogenation of indole derivatives. Selective access to tetrahydroindoles or cis-fused octahydroindoles

“…8 As for the 4,5,6,7-tetrahydroindole derivatives, they are classically formed by multistep procedures such as microwave-assisted aminolysis of 4-oxo-4,5,6,7-tetrahydrobenzofuran with different primary amines, 9 or from 1-(1-pyrrolidino)cyclohexene and chloropyruvates. 10 Only few examples have been reported so far by direct reduction of indoles. A two-step procedure including a regioselective Birch reduction followed by a catalytic hydrogenation was developed to obtain selectively the tetrahydroderivatves.…”

Tetrahydroindoles as Multipurpose Screening Compounds and Novel Sirtuin Inhibitors

“…When synthesis was conducted under acidic conditions, it promoted decarboxylation to compound 15 . Similarly, in presence of base, the ammonolysis reaction was potentially favored, converting the ester group into an unreactive primary amide. Starting the O–N substitution reaction from compound 14 , which contains a carboxylic acid, with ammonium acetate in DMF, we obtained decarboxylated indole compound 15 exclusively.…”

“…For this exchange, we used ammonium acetate [17] as an eutral ammonia releasing reagent. When synthesis was conducted under acidic conditions, it promoted decarboxylation to compound 15.Similarly,i np resence of base, the ammonolysis reaction was potentially favored, converting the ester group into an unreactive [18] primary amide. Startingt he O-N substitution reaction from compound 14,w hich containsacarboxylic acid, with ammonium acetate in DMF, we obtainedd ecarboxylated indole compound 15 exclusively.T hereupon we used the methyl ester 13 as starting product to synthesize 10.R elative to reaction with 14,s ubstitution reaction with ester derivative 13 was apparently hindered.…”

Indoles via Dehydrogenation of Pyrroles

“…Likewise, Nikolaropoulos and colleagues found DDQ to be the oxidant of choice for the conversion of dihydroindoles 3 to the corresponding indoles [10] in work patterned after Remers [2]. Taddei's group reported a microwave-assisted Stetter synthesis of 4-ketotetrahydroindoles [12]. Taddei's group reported a microwave-assisted Stetter synthesis of 4-ketotetrahydroindoles [12].…”