4132-86-9Relevant academic research and scientific papers
1,3,2-Diazaphospholenes Catalyze the Conjugate Reduction of Substituted Acrylic Acids
Reed, John H.,Cramer, Nicolai
, p. 4262 - 4266 (2020/07/13)
The potent nucleophilicity and remarkably low basicity of 1,3,2-diazaphospholenes (DAPs) is exploited in a catalytic, metal-free 1,4-reduction of free α,β-unsaturated carboxylic acids. Notably, the reduction occurs without a prior deprotonation of the carboxylic acid moiety and hence does not consume an additional hydride equivalent. This highlights the excellent nucleophilic character and low basicity of DAP-hydrides. Functional groups such as Cbz group or alkyl halides which can be problematic with classical transition-metal catalysts are well tolerated in the DAP-catalyzed process. Moreover, the transformation is characterized by a low catalyst loading, mild reaction conditions at ambient temperature as well as fast reaction times and high yields. The proof-of-principle for a catalytic enantioselective version is described.
A palladium nanoparticle-nanomicelle combination for the stereo-selective semihydrogenation of alkynes in water at room temperature
Slack, Eric D.,Gabriel, Christopher M.,Lipshutz, Bruce H.
supporting information, p. 14051 - 14054 (2015/02/19)
The addition of NaBH4 to Pd(OAc) 2 in water containing nanomicelles leads to the generation of H2 and Pd nanoparticles. Subsequent reduction of disubstituted alkynes affords Z-alkenes in high yields. These reactions are general, take place in water at ambient temperatures, and offer recycling of the aqueous reaction mixture along with low overall E Factors.
Regioselective double Boekelheide reaction: First synthesis of 3,6-dialkylpyrazine-2,5-dicarboxaldehydes from dl-alanine
Das, Sajal Kumar,Frey, Joseph
scheme or table, p. 3869 - 3872 (2012/08/14)
Pyrazine-2,5-dicarboxaldehyde was synthesized on a multi-gram scale by MnO2 oxidation of 2,5-bis(hydroxymethyl)pyrazine, which in turn was obtained from 2,5-dimethylpyrazine employing double Boekelheide reaction as a key step as reported previously. This reaction was subsequently utilized in a regioselective fashion as a key step to synthesize efficiently, for the first time, 3,6-di(long-chain)alkylpyrazine-2,5-dicarboxaldehydes starting from dl-alanine. These monomers are certain to have importance as electron deficient and chemically versatile components for new materials development.
Resolution of non-proteinogenic amino acids via microbial lipase-catalyzed enantioselective transesterification
Miyazawa, Toshifumi,Mio, Motoe,Watanabe, Yuko,Yamada, Takashi
, p. 219 - 224 (2008/09/20)
A number of non-proteinogenic amino acids bearing aliphatic side chains were resolved with moderate to good enantioselectivities (E = 15-42) through the Burkholderia cepacia lipase-catalyzed enantioselective transesterification of the 2,2,2-trifluoroethyl esters of their N-benzyloxycarbonyl derivatives with methanol as a nucleophile in diisopropyl ether.
A Stereoselective entry into functionalized 1,2-diamines by zinc-mediated homologation of α-aminoacids
Hoang, Cam Thuy,Alezra, Valerie,Guillot, Regis,Kouklovsky, Cyrille
, p. 2521 - 2524 (2008/02/05)
A general, stereoselective synthsis of 4,5-disubstituted imidazolidines-2-ones from α-aminoacids has been developed: the key steps are a Biaise reaction of bromoacetate on α-aminonitriles and further reduction. Although reduction with sodium cyanoborohydride afforded a mixture of cis and trans isomers 6a-e with moderate to good stereoselectivity, reduction with sodium in liquid ammonia gave the trans isomers 8a-e with complete stereoselectivity. Acidic hydrolysis of the urea gave 4-amino-pyrrolidinones, which can be precursors to β,γ-diaminoacids or 3-aminopyrrolidines.
Resolution of non-protein amino acids via Carica papaya lipase-catalyzed enantioselective transesterification
Miyazawa, Toshifumi,Onishi, Kazuki,Murashima, Takashi,Yamada, Takashi,Tsai, Shau-Wei
, p. 2569 - 2573 (2007/10/03)
Carica papaya lipase-catalyzed transesterification of the 2,2,2-trifluoroethyl esters of N-benzyloxycarbonylated dl-amino acids carrying aliphatic side chains proceeded smoothly and, in almost all the cases, enantiospecifically (E = >200), affording the l-methyl esters and leaving the d-trifluoroethyl esters intact.
Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 17. Preparation of aliphatic amino acid derived γ-alkoxycarbonyl-amino-β-oxo ylides and pyrolysis to give α,β-acetylenic γ-amino acid and GABA analogues
Aitken, R. Alan,Karodia, Nazira,Massil, Tracy,Young, Robert J.
, p. 533 - 541 (2007/10/03)
A series of eleven α-aminoacyl stabilised phosphorus ylides 9-19 have been prepared by condensation of N-alkoxycarbonyl protected amino acids with Ph3P = CHCO2Et using a carbodiimide peptide coupling reagent. Upon flash vacuum pyrolysis at 600 °C, these undergo extrusion of Ph3PO to give the corresponding α,β-acetylenic γ-amino esters 21-29, 33 and 34 in moderate yield. In two cases the terminal alkynes 30 and 31 are also formed. The β-aminoacyl ylide 20 from β-alanine similarly gives the α,β-acetylenic δ-amino ester 35 upon pyrolysis. Regioselective addition of HBr to the triple bond of one acetylenic ester 25 was observed giving a mixture of E and Z α-bromoacrylates 36. Hydrogenation of the N-Cbz acetylenic esters 21-23 and 33 results in N-deprotection and hydrogenation of the triple bond to afford the chiral GABA analogues 37-40 in 70 ->95% ee as determined by 19F NMR of their Mosher amides. Fully assigned 13C NMR spectra of all the ylides and acetylenic ester derivatives are presented.
Indium metal as a reducing agent in organic synthesis
Pitts,Harrison,Moody
, p. 955 - 977 (2007/10/03)
The low first ionisation potential (5.8 eV) of indium coupled with its stability towards air and water, suggest that this metallic element should be a useful reducing agent for organic substrates. The use of indium metal for the reduction of C=N bonds in imines, the heterocyclic ring in benzo-fused nitrogen heterocycles, of oximes, nitro compounds and conjugated alkenes and the removal of 4-nitrobenzyl protecting groups is described. Thus the heterocyclic ring in quinolines, isoquinolines and quinoxalines is selectively reduced using indium metal in aqueous ethanolic ammonium chloride. Treatment of a range of aromatic nitro compounds under similar conditions results in selective reduction of the nitro groups; ester, nitrile, amide and halide substituents are unaffected. Likewise indium in aqueous ethanolic ammonium chloride is an effective method for the deprotection of 4-nitrobenzyl ethers and esters. Indium is also an effective reducing agent under non-aqueous conditions and α-oximino carbonyl compounds can be selectively reduced to the corresponding N-protected amine with indium powder, acetic acid in THF in the presence of acetic anhydride or di-tert-butyl dicarbonate. Conjugated alkenes are also reduced by indium in THF-acetic acid.
A novel concept in combinatorial chemistry in solution with the advantages of solid-phase synthesis: Formation of N-betaines by multicomponent domino reactions
Tietze, Lutz F.
, p. 903 - 905 (2007/10/03)
Advantages of solid-phase and liquid-phase synthesis are combined in a new concept of combinatorial chemistry: a domino sequence comprising Knoevenagel and hetero-Diels-Alder reactions, with subsequent hydrogenation starting from protected aminoaldehydes, 1.3-dicarbonyl compounds, and enol ethers leads to N-heterocycles of high diversity with a betaine structure, which are isolated in highly pure form by precipitation with diethyl ether (see scheme), Cbz = benzylocycarbonyl, Bn = benzyl.
Indium as a reducing agent: Deprotection of 4-nitrobenzyl ethers and esters
Moody, Christopher J.,Pitts, Michael R.
, p. 1575 - 1576 (2007/10/03)
Indium in aqueous ethanolic ammonium chloride is an effective method for the deprotection of 4-nitrobenzyl ethers and esters.
