30800-90-9Relevant academic research and scientific papers
Diversification of Unprotected Alicyclic Amines by C?H Bond Functionalization: Decarboxylative Alkylation of Transient Imines
Paul, Anirudra,Kim, Jae Hyun,Daniel, Scott D.,Seidel, Daniel
supporting information, p. 1625 - 1628 (2020/11/30)
Despite extensive efforts by many practitioners in the field, methods for the direct α-C?H bond functionalization of unprotected alicyclic amines remain rare. A new advance in this area utilizes N-lithiated alicyclic amines. These readily accessible intermediates are converted to transient imines through the action of a simple ketone oxidant, followed by alkylation with a β-ketoacid under mild conditions to provide valuable β-amino ketones with unprecedented ease. Regioselective α′-alkylation is achieved for substrates with existing α-substituents. The method is further applicable to the convenient one-pot synthesis of polycyclic dihydroquinolones through the incorporation of a SNAr step.
Synthesis of a 3,4-Dihydro-1,3-oxazin-2-ones Skeleton via an Intermolecular [4 + 2] Process of N-Acyliminium Ions with Ynamides/Terminal Alkynes
Han, Xiao-Li,Nie, Xiao-Di,Chen, Zhao-Dan,Si, Chang-Mei,Wei, Bang-Guo,Lin, Guo-Qiang
, p. 13567 - 13578 (2020/11/13)
An approach to access functionalized 3,4-dihydro-1,3-oxazin-2-ones has been developed by reacting semicyclic N,O-acetals 5 and 6 with ynamides 7 or terminal alkynes 8 in a one-pot fashion. The reaction went through a formal [4 + 2] cycloaddition process to generate a number of functionalized 3,4-dihydro-1,3-oxazin-2-ones 9a-9ak and 10a-10bc in yields of 34-97%. In addition, the utility of this transformation was demonstrated by the synthesis of (±)-sedamine 13.
Mannich-type Reactions of Cyclic Nitrones: Effective Methods for the Enantioselective Synthesis of Piperidine-containing Alkaloids
Lisnyak, Vladislav G.,Lynch-Colameta, Tessa,Snyder, Scott A.
supporting information, p. 15162 - 15166 (2018/10/26)
Even though there are dozens of biologically active 2-substituted and 2,6-disubstituted piperidines, only a limited number of approaches exist for their synthesis. Herein is described two Mannich-type additions to nitrones, one using β-ketoacids under catalyst-free conditions and another using methyl ketones in the presence of chiral thioureas, which can generate a broad array of such 2-substituted materials, as well as other ring variants, in the form of β-N-hydroxy-aminoketones. Both processes have broad scope, with the latter providing products with high enantioselectivity (up to 98 %). The combination of these methods, along with other critical steps, has enabled 8-step total syntheses of the 2,6-disubstituted piperidine alkaloids (?)-lobeline and (?)-sedinone.
Biomimetic synthesis of 2-substituted N-heterocycle alkaloids by one-pot hydrolysis, transamination and decarboxylative Mannich reaction
Galman, James L.,Slabu, Iustina,Parmeggiani, Fabio,Turner, Nicholas J.
supporting information, p. 11316 - 11319 (2018/10/24)
Heterocycles based on piperidine and pyrrolidine are key moieties in natural products and pharmaceutically active molecules. A novel multi-enzymatic approach based on the combination of a lipase with an α,ω-diamine transaminase is reported, opening up the synthesis, isolation and characterisation of a broad range of 2-substituted N-heterocycle alkaloids.
Gold-catalysed synthesis of exocyclic vinylogous amides and β-amino ketones: A detailed study on the 5-exo/6-endo-dig selectivity, methodology and scope
Scarpi, Dina,Begliomini, Stefano,Prandi, Cristina,Oppedisano, Alberto,Deagostino, Annamaria,G?mez-Bengoa, Enrique,Fiser, Béla,Occhiato, Ernesto G.
, p. 3251 - 3265 (2015/05/20)
The gold(I)-catalysed reaction of N-Boc-protected 6-alkynyl-3,4-dihydro-2H-pyridines, which gives synthetically useful vinylogous amides (β-enaminones), has been studied in detail, in order to optimize the reaction conditions, enlarge the scope and gain i
Studies on the Eschenmoser coupling reaction and insights on its mechanism. Application in the synthesis of Norallosedamine and other alkaloids
Neto, Brenno A.D.,Lapis, Alexandre A.M.,Bernd, Alinne B.,Russowsky, Dennis
experimental part, p. 2484 - 2496 (2009/08/07)
The conditions of the Eschenmoser coupling reaction were studied. The formation of the α-thioiminium ion was achieved faster in the presence of an additive (NaI) and dry chloroform as the preferred solvent. The developed conditions were used for the second part of the reaction (the sulfur extrusion itself). The present protocol avoids the formation of byproducts, which were previously described as a major drawback to be overcome. Electrospray ionization tandem mass spectrometry was used to characterize some aspects (intermediates) of the first step of the reaction mechanism. Some reduction conditions were properly tested and the selected conditions were applied to the synthesis of the natural alkaloid Norallosedamine and other derivatives.
Mechanistic studies on diamine oxidase: oxidation of α,ω-diamines does not involve an enamine intermediate
Gavin, Stephen S.,Equi, Angela M.,Robins, David J.
, p. 31 - 34 (2007/10/02)
Three β,β,β',β'-2H4-labelled α,ω-diamines were synthesized and incubated with pea seedling diamine oxidase.The aminoaldehydes formed by oxidative deamination cyclized to the corresponding imines, which were trapped with benzoylacetic acid.In all three cases the acetophenone derivatives produced were shown by NMR and mass spectrometry to contain four deuterium atoms.The retention of all four deuterium atoms demonstrates that oxidative deamination of α,ω-diamines catalyzed by pea seedling diamine oxidase does not involve an enamine intermediate as previously suggested.
ALKALOIDS OF SOME EUROPEAN AND MACARONESIAN SEDOIDEAE AND SEMPERVIVOIDEAE (CRASSULACEAE)
Stevens, Jan F.,Hart, Henk 't,Hendriks, Henk,Malingre, Theo M.
, p. 3917 - 3924 (2007/10/02)
Some 22 pyrrolidine and piperidine alkaloids were detected in the leafy parts of Sedum acre, S. aetnense, S. anglicum, S. brissemoreti, S. farinosum, S. fusiforme, S. lancerottense, S. melanantherum, and S. nudum.In addition to the alkaloids known from S. acre, 1-(2-pyrrolidyl)-propan-2-one and 2-monosubstituted piperidine alkaloids bearing butan-2-one, butan-2-ol, pentan-2-one and pentan-2-ol sidechains were identified.Phenylethylamine was isolated from the vegetative parts of S. album.In S. lydium, S. meyeri-johannis, and 16 species of S. series Rupestria, Aeonium, Greenovia, Jovibarba and Sempervivum no alkaloids could be detected.The results indicate a correlation between the presence of alkaloids and the major evolutionary trends in the European and Macaronesian Crassulaceae. Key Word Index: Sedum; Aeonium; Greenovia; Jovibarba; Sempervivum; Crassulaceae; pyrrolidine and piperidine alkaloids; chemotaxonomy; evolution.
Trimethylsilyl trifluoromethanesulfonate (TMSOTf) catalyzed amidoalkylation of silylenolethers. Stereocontrolled syntheses of (+/-)-sedamine and (+/-)-norsedamine
Pilli,Dias
, p. 2213 - 2229 (2007/10/02)
Trimethylsilyl trifluoromethanesulfonate (TMSOTf) catalyzed addition of 1-trimethylsilyloxy-1-phenylethene to N-ethoxycarbonyl- and N-tert-butoxycarbonyl-2-ethoxypiperidines (3a and 3b, respectively) afforded the corresponding ketocarbamates 4a and 4b, in excellent yields. Stereoselective conversion to (±)-norsedamine (7) and (±)-sedamine (8) is described.
PEA-SEEDLING DIAMINE OXIDASE: APPLICATIONS IN SYNTHESIS AND EVIDENCE RELATING TO ITS MECHANISM OF ACTION
Cragg, John E.,Herbert, Richard B.,Kgaphola, Mashupye M.
, p. 6907 - 6910 (2007/10/02)
Diamines (6)-(8) and (11) act as acceptable substrates for diamine oxidase (DAO) and the novel phenacyl derivatives (2) are obtained in satisfactory preparative yield; no enantioselectivity is observed with (11) as an enzyme substrate.Remarkably, the triamines (9) and (13) are not oxidized and, moreover, (9) acts as a notable inhibitor for the DAO catalysed oxidation of (4) and (5).Kinetic evidence relevant to the mechanism of DAO action is presented, and is discussed in terms of a model for DAO-catalysed oxidation.
