863313-50-2Relevant academic research and scientific papers
Effective Formylation of Amines with Carbon Dioxide and Diphenylsilane Catalyzed by Chelating bis(tzNHC) Rhodium Complexes
Nguyen, Thanh V. Q.,Yoo, Woo-Jin,Kobayashi
supporting information, p. 9209 - 9212 (2015/08/06)
The reductive formylation of amines using CO2 and hydrosilanes is an attractive method for incorporating CO2 into valuable organic compounds. However, previous systems required either high catalyst loadings or high temperatures to achieve high efficiency, and the substrate scope was mostly limited to simple amines. To address these problems, a series of alkyl bridged chelating bis(NHC) rhodium complexes (NHC=N-heterocyclic carbene) have been synthesized and applied to the reductive formylation of amines using CO2 and Ph2SiH2. A rhodium-based bis(tzNHC) complex (tz=1,2,3-triazol-5-ylidene) was identified to be highly effective at a low catalyst loading and ambient temperature, and a wide substrate scope, including amines with reducible functional groups, were compatible. Beyond the norm: Rhodium complexes bearing a strong electron-donating bis(1,2,3-triazol-5-ylidene) ligand were found to be excellent catalysts for the reductive formylation of amines with CO2 and Ph2SiH2 at ambient temperature. The catalyst system possesses a broad substrate scope which tolerates a variety of reducible functional groups and is suitable for the synthesis of bioactive compounds. Tf=trifuoromethanesulfonyl.
Formylation of amines catalysed by protic ionic liquids under solvent-free condition
Majumdar, Swapan,De, Jhinuk,Hossain, Jewel,Basak, Ajoy
, p. 262 - 266 (2013/02/22)
A fast, efficient and simple route for the N-formylation of amines has been developed by treating amines with 85% formic acid at 70°C in the presence of 5 mol % of protic ionic liquid as catalyst under solvent-free condition. This method provides a green and much improved protocol over the existing methods.
Generation and cyclization of unsaturated carbamoyl radicals derived from S-4-pentynyl carbamothioates under tin-free conditions
Benati, Luisa,Bencivenni, Giorgio,Leardini, Rino,Minozzi, Matteo,Nanni, Daniele,Scialpi, Rosanna,Spagnolo, Piero,Zanardi, Giuseppe
, p. 3192 - 3197 (2007/10/03)
The radical reaction of benzenethiol with S-4-pentynyl carbamothioates provides a valuable protocol for the tin-free generation of carbamoyl radicals, which arise from intramolecular substitution at sulfur by the initial sulfanylvinyl radicals. This procedure can be usefully employed to achieve N-benzylcarbamoyl radical 5-exo and 4-exo cyclizations leading, respectively, to pyrrolidinones and azetidinones, although, for the latter, it seems of lesser utility. Novel evidence is presented that. N-tosyl-substituted carbamoyl radicals display a peculiar tendency to yield the corresponding isocyanate by β-elimination of the tosyl radical.
Intramolecular Diels-Alder reactions. 5. Approaches to the pyrrolo[3,4-c]carbazole and pyrido[4,3-c]carbazole systems
Ciganek,Schubert
, p. 4629 - 4634 (2007/10/02)
Two methods for the preparation of indole-2,3-quinodimethanes are reported. Treatment of 1,2-dimethyl-α-oxo-N-(phenylmethyl)-N-2-propenyl-1H-indole-3-acetamid e (3) with sodium bis(trimethylsilyl)amide in refluxing THF gave 2-(phenylmethyl)-10c-hydroxy-6-methyl-3,3a,4,5,6,10c-hexahydropyrrolo[ 3,4-c]carbazol-1(2H)-one (5) in 18% yield by intramolecular Diels-Alder reaction of the intermediate enolate 4. LiBH4-reduction of amide 3 and thermolysis of the resulting α-hydroxyamide 8 at 190°C gave a 63:37 mixture of the cis and trans isomers of 2-(phenylmethyl)-6-methyl-3,3a,4,5,6,10c-hexahydropyrrolo[3,4-c]carbaz ol-1(2H)-one (9a and 9b) in 64% yield. The corresponding N-3-butenylamide 10 at 205°C led to a 67:33 mixture of cis-and trans-7-methyl-2,3,4,4a,5,6,7,11c-octahydro-2-(phenylmethyl)-1H-pyrido [4,3-c]carbazol-1-one (11a and 11b) in 53% yield. Thermolysis of 1,2-dimethyl-α-hydroxy-N-(phenylmethyl)-N-2-propynyl-1H-indole-3-acet amide (15) gave an equimolar mixture of lactam 9a and the aromatized product, 3,6-dihydro-6-methyl-2-(phenylmethyl)pyrrolo[3,4-c]carbazol-1(2H)-one (17) in 80% yield by disproportionation of the intermediate lactam 16. Reaction of 1,2-dimethyl-1H-indole-3-carboxaldehyde with methyl acrylate and sodium bis(trimethylsilyl)amide produced methyl 1,2-dihydro-9-methyl-9H-carbazole-3-carboxylate (20) in 26% yield, most likely by a sequence of Michael addition to the enolate of the aldehyde and intramolecular aldol condensation.
