- Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides
-
The synthesis of a novel category of pseudo-peptides via intramolecular Ugi reaction of levulinic acid (4-oxopentanoic acid), aromatic and aliphatic amines, and amino acid-based isocyanides is reported. Levulinic acid was applied as a bifunctional substrate containing both carbonyl and acid moieties suitable for the Ugi reaction. This article provides a facile and convenient one-pot procedure for the synthesis of peptide-like heterocyclic molecules containing 2-pyrrolidone (γ-lactam), amide and ester functional groups with good to excellent yields.
- Khalesi, Maryam,Halimehjani, Azim Ziyaei,Martens, Jürgen
-
-
Read Online
- Transition Metal-Free N-Arylation of Amino Acid Esters with Diaryliodonium Salts
-
A transition metal-free approach for the N-arylation of amino acid derivatives has been developed. Key to this method is the use of unsymmetric diaryliodonium salts with anisyl ligands, which proved important to obtain high chemoselectivity and yields. The scope includes the transfer of both electron deficient, electron rich and sterically hindered aryl groups with a variety of different functional groups. Furthermore, a cyclic diaryliodonium salt was successfully employed in the arylation. The N-arylated products were obtained with retained enantiomeric excess.
- Kervefors, Gabriella,Kersting, Leonard,Olofsson, Berit
-
supporting information
p. 5790 - 5795
(2021/03/08)
-
- Chiral polycyclic tropane compound as well as preparation method and application thereof
-
The invention provides a chiral polycyclic tropane compound as well as a preparation method and application thereof. The invention specifically relates to a tropane compound shown as a formula I, or a salt thereof, or a stereoisomer thereof, or a crystal form thereof, and a preparation method and application thereof. The preparation method disclosed by the invention is simple in process, mild in reaction condition and high in yield, and the obtained product has excellent enantioselectivity and diastereoselectivity. Experiments prove that the tropane compound can effectively inhibit various tumor cells, especially lung cancer cells, melanoma cells, breast cancer cells, in-situ pancreatic cancer cells and pancreatic cancer cells, so that the compound has a wide prospect in preparation of drugs for preventing and/or treating tumors.
- -
-
Paragraph 0110-0113
(2021/08/25)
-
- Synthesis and Penicillin-binding Protein Inhibitory Assessment of Dipeptidic 4-Phenyl-β-lactams from α-Amino Acid-derived Imines
-
Monocyclic β-lactams revive the research field on antibiotics, which are threatened by the emergence of resistant bacteria. A six-step synthetic route was developed, providing easy access to new 3-amino-1-carboxymethyl-4-phenyl-β-lactams, of which the penicillin-binding protein (PBP) inhibitory potency was demonstrated biochemically.
- Decuyper, Lena,Juki?, Marko,Sosi?, Izidor,Amoroso, Ana Maria,Verlaine, Olivier,Joris, Bernard,Gobec, Stanislav,D'hooghe, Matthias
-
supporting information
p. 51 - 55
(2019/11/28)
-
- Bioinspired Radical Stetter Reaction: Radical Umpolung Enabled by Ion-Pair Photocatalysis
-
A bioinspired, intermolecular radical Stetter reaction of α-keto acids and aldehydes is disclosed that is contingent on a formal “radical umpolung” concept. Enabled by secondary amine activation, electrostatic recognition ensures that the α-ketocarboxylic acids, which function as latent acyl radicals, are proximal to the in situ generated iminium salts. This photoactive contact ion pair is an electron donor–acceptor (EDA) complex, and undergoes facile single electron transfer (SET) and rapid decarboxylation prior to radical–radical recombination. Importantly, decarbonylation is mitigated by this strategy. The initial computational validation on which the process is predicated matches closely with experiment. Synergising organo- and photocatalysis activation principles finally expands the mechanistic and synthetic scope of the classic Stetter reaction to include α,β-unsaturated aldehydes as acceptors.
- Morack, Tobias,Mück-Lichtenfeld, Christian,Gilmour, Ryan
-
supporting information
p. 1208 - 1212
(2019/01/04)
-
- Controllable Intramolecular Unactivated C(sp3)-H Amination and Oxygenation of Carbamates
-
Dual catalyst-controlled intramolecular unactivated C(sp3)-H amination and oxygenation of carbamates merging visible-light photocatalysis and earth-abundant transition metal catalysis have been reported. Useful amino alcohol and diol derivatives could be selectively obtained from readily available tertiary alcohol derivatives. The possible mechanisms have been proposed via a 1,5-HAT process followed by Lewis acid-controlled cyclization. The nickel and zinc catalysts inhibit the formation of oxygenation and amination products, respectively. An interesting phenomenon of chirality transfer is also observed.
- Guo, Qihang,Ren, Xiang,Lu, Zhan
-
supporting information
p. 880 - 884
(2019/05/16)
-
- Regiodivergent Enantioselective γ-Additions of Oxazolones to 2,3-Butadienoates Catalyzed by Phosphines: Synthesis of α,α-Disubstituted α-Amino Acids and N,O-Acetal Derivatives
-
Phosphine-catalyzed regiodivergent enantioselective C-2- and C-4-selective γ-additions of oxazolones to 2,3-butadienoates have been developed. The C-4-selective γ-addition of oxazolones occurred in a highly enantioselective manner when 2-aryl-4-alkyloxazol-5-(4H)-ones were employed as pronucleophiles. With the employment of 2-alkyl-4-aryloxazol-5-(4H)-ones as the donor, C-2-selective γ-addition of oxazolones took place in a highly enantioselective manner. The C-4-selective adducts provided rapid access to optically enriched α,α-disubstituted α-amino acid derivatives, and the C-2-selective products led to facile synthesis of chiral N,O-acetals and γ-lactols. Theoretical studies via DFT calculations suggested that the origin of the observed regioselectivity was due to the distortion energy that resulted from the interaction between the nucleophilic oxazolide and the electrophilic phosphonium intermediate.
- Wang, Tianli,Yu, Zhaoyuan,Hoon, Ding Long,Phee, Claire Yan,Lan, Yu,Lu, Yixin
-
supporting information
p. 265 - 271
(2016/01/25)
-
- A new type of chiral-pyridoxamines for catalytic asymmetric transamination of α-keto acids
-
A new type of chiral pyridoxamines bearing an adjacent chiral stereocenter has been developed via multi-step synthesis. The pyridoxamines displayed catalytic activity in asymmetric transamination of α-keto acids to give a variety of optically active amino acids in 27–78% yields with 34–62% ee's under very mild conditions. This work provides a synthetic strategy to construct new chiral pyridoxamines using bromopyridine 7 as a key synthon and also represents an early example of the applications of chiral pyridoxamines in asymmetric catalysis.
- Chen, Jianfeng,Zhao, Junyu,Gong, Xing,Xu, Dongfang,Zhao, Baoguo
-
supporting information
p. 4612 - 4615
(2016/09/23)
-
- A PRODUCING METHOD OF D-FORM OR L-FORM AMINO ACID DERIVATIVES HAVING A THIOL GROUP
-
This invention provides a producing method of an optical active D-form and/or L-form amino acid having a thiol group on its side chain by a simple method with good yield. This invention provides a producing method of an amino acid derivative having a thiol group on its side chain, and an intermediate thereof, wherein the producing method is characterized by producing an intermediate composition comprising a D-form and L-form of amino acid derivate having a thiol group at β -position, reacting D- or L-amino acid selective hydrolytic enzyme, and isolating the hydrolyzed D- or L-amino acid derivative.
- -
-
Paragraph 0152; 0153
(2016/10/31)
-
- Amino acid bioconjugation via iClick reaction of an oxanorbornadiene-masked alkyne with a MnI(bpy)(CO)3-coordinated azide
-
The catalyst-free room temperature iClick reaction of an unsymmetrically 2,3-disubstituted oxanorbornadiene (OND) as a "masked" alkyne equivalent with [Mn(N3)(bpy CH3,CH3)(CO)3] leads to isolation of a phenylalanine ester bioconjugate, in which the model amino acid is linked to the metal moiety via a N-2-coordinated triazolate formed in a cycloaddition-retro-Diels-Alder (crDA) reaction sequence, in a novel approach to bioorthogonal coupling reactions based on metal-centered reactivity.
- Henry, Lucas,Schneider, Christoph,Mützel, Benedict,Simpson, Peter V.,Nagel, Christoph,Fucke, Katharina,Schatzschneider, Ulrich
-
supporting information
p. 15692 - 15695
(2015/02/19)
-
- Triple role of phenylselenonyl group enabled a one-pot synthesis of 1,3-oxazinan-2-ones from α-isocyanoacetates, phenyl vinyl selenones, and water
-
Reaction of α-substituted α-isocyanoacetates with phenyl vinyl selenones in the presence of a catalytic amount of base (DBU or Et3N, 0.05-0.1 equiv) followed by addition of p-toluenesulfonic acid (PTSA, 0.1-0.2 equiv) afforded 4,4,5-trisubstituted 1,3-oxazinan-2-ones in good to excellent yields. Enantiomerically enriched heterocycles can also be prepared using a Cinchona alkaloid-derived bifunctional organocatalyst for the Michael addition step. The phenylselenonyl group served as an activator for the Michael addition, a leaving group and a latent oxidant in this integrated reaction sequence.
- Buyck, Thomas,Wang, Qian,Zhu, Jieping
-
supporting information
p. 11524 - 11528
(2014/10/15)
-
- Asymmetric chemoenzymatic synthesis of N-acetyl-α-amino esters based on lipase-catalyzed kinetic resolutions through interesterification reactions
-
Several phenylalanine analogs have been synthesized through a four-step route starting from easily available ethyl acetamidocyanoacetate. In a first reaction, and making use of phase transfer catalysts, this compound reacted with several alkyl halides, being benzyltributylammonium chloride identified as the best one for the production of a series of quaternary amino acids in moderate to excellent yields (52-95%). Then, the corresponding N-acetyl-phenylalanine methyl and allyl ester derivatives were obtained through acidic hydrolysis, esterification, and N-acetylation. Rhizomucor miehei lipase was found as a versatile enzyme for the resolution of these amino esters, finding the best results through interesterification reactions with butyl butyrate in acetonitrile. A great influence in the stereoselectivity was found depending on the chemical structure of the compound, achieving for the non- or para-substituted in the phenyl ring excellent stereoselectivities, being moderate for the meta-nitro derivative, while the ortho-nitro amino ester did not react.
- Da Silva, Marcos Reinaldo,De Mattos, Marcos Carlos,De Oliveira, Maria Da Concei??o Ferreira,De Lemos, Telma Leda Gomes,Ricardo, Nágila Maria Pontes Silva,De Gonzalo, Gonzalo,Lavandera, Iván,Gotor-Fernández, Vicente,Gotor, Vicente
-
p. 2264 - 2271
(2014/03/21)
-
- Design and bio-evaluation of indole derivatives as potent Kv1.5 inhibitors
-
Atrial fibrillation (AF) is one of the common arrhythmias that threaten human health. Kv1.5 potassium channel is reported as an efficacious and safe target for the treatment of AF. In this paper, we designed and synthesized three series of compounds through modifying the lead compound RH01617 that was screened out by the pharmacophore model we reported earlier. All of the compounds were evaluated by the whole-patch lamp technology and most of them possessed potent inhibitory activities against Kv1.5. Compounds IIIi and IIIl were evaluated for the target selectivity as well as the pharmacodynamic effects in an isolated rat model. Due to the promising pharmacological behavior, compound IIIl deserves further pharmacodynamic and pharmacokinetic evaluations.
- Guo, Xiaoke,Yang, Qian,Xu, Jing,Zhang, Li,Chu, Hongxi,Yu, Peng,Zhu, Yingying,Wei, Jinglian,Chen, Weilin,Zhang, Yaozhong,Zhang, Xiaojin,Sun, Haopeng,Tang, Yiqun,You, Qidong
-
p. 6466 - 6476
(2013/10/22)
-
- Iron-catalyzed oxidative C - H/C - H cross-coupling: An efficient route to α-quaternary α-amino acid derivatives
-
Fully loaded: A coordinating activation strategy has been developed to furnish α-quaternary α-amino acids through the iron(III)-catalyzed oxidative functionalization of α-C(sp3) - H bonds of α-tertiary α-amino acid esters. The reaction exhibits a broad substrate scope for both α-amino acids and nucleophiles (Nu) as well as good functional-group tolerance (see scheme, DTBP=di-tert-butyl peroxide, DCE=1,2-dichloroethane). Copyright
- Li, Kaizhi,Tan, Guangying,Huang, Jingsheng,Song, Feijie,You, Jingsong
-
supporting information
p. 12942 - 12945
(2014/01/06)
-
- Enzymatic synthesis of chiral phenylalanine derivatives by a dynamic kinetic resolution of corresponding amide and nitrile substrates with a multi-enzyme system
-
Mutant α-amino-ε-caprolactam (ACL) racemase (L19V/L78T) from Achromobacter obae with improved substrate specificity toward phenylalaninamide was obtained by directed evolution. The mutant ACL racemase and thermostable mutant D-amino acid amidase (DaaA) from Ochrobactrum anthropi SV3 co-expressed in Escherichia coli (pACLmut/pDBFB40) were utilized for synthesis of (R)-phenylalanine and non-natural (R)-phenylalanine derivatives (4-OH, 4-F, 3-F, and 2-F-Phe) by dynamic kinetic resolution (DKR). Recombinant E. coli with DaaA and mutant ACL racemase genes catalyzed the synthesis of (R)-phenylalanine with 84% yield and 99% ee from (RS)-phenylalaninamide (400 mM) in 22 h. (R)-Tyrosine and 4-fluoro-(R)-phenylalanine were also efficiently synthesized from the corresponding amide compounds. We also co-expresed two genes encoding mutant ACL racemase and L-amino acid amidase from Brevundimonas diminuta in E. coli and performed the efficient production of various (S)-phenylalanine derivatives. Moreover, 2-aminophenylpropionitrile was converted to (R)-phenylalanine by DKR using a combination of the non-stereoselective nitrile hydratase from recombinamt E. coli and mutant ACL racemase and DaaA from E. coli encoding mutant ACL racemase and DaaA genes. Copyright
- Yasukawa, Kazuyuki,Asano, Yasuhisa
-
supporting information
p. 3327 - 3332
(2013/01/15)
-
- Synthesis, crystal structure and insecticidal activity of the optical active neonicotinoid analogues
-
Eight novel neonicotinoid analogues 1-(2-tetrahydrofurfuryl)-5-substituted- 1,3,5-hexahydrotriazine-2-N-nitroimines 3a - 3h were synthesized, and their structures were characterized by 1H NMR, IR and elemental analysis. The stereostructure of 3a was determined by the single-crystal X-ray analysis, which exhibits a half-chair conformation and dihedral angle is 49.70° . The preliminary bioassay tests showed that all the title compounds exhibited good insecticide activities against Nilaparvata legen (N. legen).
- Xue, Sijia,Bu, Hongfei,Liu, Li,Xu, Xiao,Ma, Xubo
-
scheme or table
p. 1011 - 1016
(2012/01/06)
-
- Structural diversity-guided convenient construction of functionalized polysubstituted butenolides and lactam derivatives
-
A molecular diversity-oriented convenient access to multi-substituted butenolides and lactam scaffolds via four different methods from various phenylacetic acid derivatives is described. The target molecules have been identified on the basis of analytical spectra data, and are useful synthons in the fields of medicine and agrochemicals.
- Ke, Shaoyong,Zhang, Ya-Ni,Shu, Wenming,Zhang, Zhigang,Shi, Liqiao,Liang, Ying,Wang, Kaimei,Yang, Ziwen
-
experimental part
p. 1071 - 1079
(2012/03/12)
-
- Synthesis of novel hyperbranched poly(ester-amide)s based on neutral α-amino acids via "aD + CBB′" couple-monomer approach
-
A series of novel hyperbranched poly(ester-amide)s (HBPEAs) based on neutral α-amino acids have been synthesized via the "AD + CBB′" couple-monomer approach. The ABB′ intermediates were stoichiometrically formed through thio-Michael addition reaction because of reactivity differences between functional groups. Without any purification, in situ self-polycondensations of the intermediates at elevated temperature in the presence of a catalyst afforded HBPEAs with multihydroxyl end groups. The degrees of branching (DBs) of the HBPEAs were estimated to be 0.40-0.58 and 0.24-0.54 by quantitative 13C NMR with two different calculation methods, respectively, depending on polymerization conditions and structure of monomers. The influences of catalyst, temperature, and intermediate structure on the polymerization process and molecular weights as well as properties of the resultant polymers were investigated. FTIR, NMR, and DEPT-135 NMR analyses revealed the branched structure of the resultant polymers. The HBPEAs possess moderately high molecular weights with broad distributions, glass transition temperatures in the range of -25.5 to 36.5 °C, and decomposition temperatures at 10% weight loss under nitrogen and air in the regions of 243.4-289.1 °C and 231.4-265.6 °C, respectively. Among them, those derived from D,L-phenylalanine display the lowest degree of branching, whereas the highest glass transition temperature and the best thermal stability.
- Bao, You-Mei,Liu, Xiao-Hui,Tang, Xiu-Lan,Li, Yue-Sheng
-
experimental part
p. 5364 - 5374
(2011/06/21)
-
- Sonogashira and "click" reactions for the N-terminal and side-chain functionalization of peptides with [Mn(CO)3(tpm)] +-based CO releasing molecules (tpm = tris(pyrazolyl)methane)
-
A recently identified photoactivatable CO releasing molecule (CORM) based on [Mn(CO)3(tpm)]+ was conjugated to functionalized amino acids and model peptides using the Pd-catalyzed Sonogashira cross-coupling and the alkyne-azide 1,3-dipolar cycloaddition ("Click reaction"). Both were found to be fully compatible with all functional groups present. The CORM-peptide conjugates were isolated in reasonable yield and high purity, as indicated by IR spectroscopy, ESI mass spectrometry and RP-HPLC. The myoglobin assay was used to demonstrate that they have CO release properties identical those of the parent compound. This work thus opens the way for a targeted delivery of CORMs to cellular systems.
- Pfeiffer, Hendrik,Rojas, Alfonso,Niesel, Johanna,Schatzschneider, Ulrich
-
supporting information; experimental part
p. 4292 - 4298
(2009/10/09)
-
- Design and synthesis of N-methylmaleimide indolocarbazole bearing modified 2-acetamino acid moieties as Topoisomerase I inhibitors
-
A novel series of N-methylmaleimide indolocarbazole derivatives bearing modified 2-acetamino acid moieties are first reported. The cytotoxic effects of these compounds were tested in five human tumor cell lines. The potent compounds 9a, 9b, 9d, and 9e have been further evaluated for their effect on Topoisomerase I (TOPO I) and cancer cell cycle. It is concluded that the indolocarbazoles with alkyl piperazine or morpholine substituent groups instead of esters or glycosyl residues would have better activities against tumors.
- Li, Zhiyu,Zhai, Fuming,Zhao, Li,Guo, Qinglong,You, Qidong
-
scheme or table
p. 406 - 409
(2011/02/26)
-
- Complete deracemization by attrition-enhanced Ostwald ripening elucidated
-
(Chemical Equation Presented) Shaken and stirred: The emergence of single chirality in the solid state during grinding of a slurry has been kinetically studied for a phenylglycine amide (see scheme). The insight obtained into the underlying process of attrition-enhanced Ostwald ripening enables the definition of suitable conditions to increase the deracemization rate drastically.
- Noorduin, Wim L.,Meekes, Hugo,Van Enckevort, Willem J. P.,Millemaggi, Alessia,Leeman, Michel,Kaptein, Bernard,Kellogg, Richard M.,Vlieg, Elias
-
supporting information; experimental part
p. 6445 - 6447
(2009/03/11)
-
- Attrition-enhanced deracemization of an amino acid derivative that forms an epitaxial racemic conglomerate
-
(Chemical Equation Presented) Just bead it! Despite the complication of enantiomeric epitaxial behavior, a derivative of phenylalanine was completely resolved (see picture). Racemization takes place by abrasively grinding crystals of the compound in a saturated solution. By studying the influence of different crystal sizes, it was found that Ostwald ripening plays an important role in this process. DBU = 1,8-diazabicyclo-[5.4.0]undec-7-ene.
- Kaptein, Bernard,Noorduin, Wim L.,Meekes, Hugo,Van Enckevort, Willem J. P.,Kellogg, Richard M.,Vlieg, Elias
-
supporting information; experimental part
p. 7226 - 7229
(2009/04/10)
-
- A convenient synthesis of amino acid methyl esters
-
A series of amino acid methyl ester hydrochlorides were prepared in good to excellent yields by the room temperature reaction of amino acids with methanol in the presence of trimethylchlorosilane. This method is not only compatible with natural amino acids, but also with other aromatic and aliphatic amino acids.
- Li, Jiabo,Sha, Yaowu
-
p. 1111 - 1119
(2008/09/21)
-
- Probing the efficiency of N-heterocyclic carbene promoted O- to C-carboxyl transfer of oxazolyl carbonates
-
(Chemical Equation Presented) Screening of a range of azolium salts, bases and solvents for reactivity indicates that triazolinylidenes, generated in situ with KHMDS in THF, promote the Steglich rearrangement of oxazolyl carbonates with high catalytic efficiency (typical reaction time 5 min at 1.5 mol % NHC). This protocol shows wide substrate applicability, even allowing the efficient generation of vicinal quaternary centers. An improved experimental procedure is also described that allows a simplified one-pot reaction protocol to be employed with similarly high catalytic efficiency.
- Thomson, Jennifer E.,Campbell, Craig D.,Concellon, Carmen,Duguet, Nicolas,Rix, Kathryn,Slawin, Alexandra M. Z.,Smith, Andrew D.
-
p. 2784 - 2791
(2008/09/20)
-
- Simple and effective preparation of amino sulfonylureas from amino acids: application to the synthesis of amino sulfonylurea-containing peptidomimetics
-
Several amino sulfonylureas have been synthesized, starting from amino acids. The synthetic procedure is simple affording high yields of products under mild conditions. Furthermore, it is shown that these compounds can be incorporated into a peptide sequence.
- ?ink, Roman,Zega, Anamarija
-
p. 3943 - 3945
(2008/09/21)
-
- Alkylation of N′-[(S)-1′-phenylethyl]-N-(diphenylmethylene)glycinamide using a phase transfer catalyst (PTC) for practical asymmetric syntheses of α-amino acid derivatives
-
The chiral auxiliary mediated stereoselective alkylation reaction of N′-[(S)-1′-phenylethyl]-N-(diphenylmethylene)glycinamide (1) using a phase transfer catalyst (PTC) is described. Alkylation of 1 using 18-crown-6 as a PTC for liquid-solid extraction of KOH in toluene gives best results. This methodology provides a practical protocol for the preparation of a variety of enantio-enriched unnatural α-amino acid derivatives up to 83:17 enantiomeric ratio.
- Kim, Hyun Ju,Lee, Sang-Kuk,Park, Yong Sun
-
p. 613 - 616
(2007/10/03)
-
- New 2-(2'-phenyl-9'-benzyl-8'-azapurin-6'-ylamino)-carboxylic acid methylesters as ligands for A1 adenosine receptors.
-
Synthesis of a series of new 2-phenyl-9-benzyl-8-azaadenines bearing on N6 an alkyl or aralkyl chain having a carbonyloxymethyl group on the carbon bound to N6 were reported. The ester group could assure to the molecule a better water-solubility than the 8-azaadenines 2, 6 and 9 substituted with lipophilic groups synthesised in the past. Compounds synthesised demonstrated only little capability of binding A1 adenosine receptors.
- Biagi,Giorgi,Pacchini,Livi,Scartoni
-
p. 929 - 931
(2007/10/03)
-
- Deracemization process of α-aminoesters via pyridoxal. I.- Synthesis and activity of polymerizable forms of pyridoxal
-
In order to immobilize pyridoxal, which is a racemization agent of α-aminoesters and could be used in an α-aminoacid deracemization process, two polymerizable analogues of this coenzyme have been synthesized.They were obtained by functionalization in the 2' or 5' position of the pyridinic ring, by a chain containing an acryloyl end group.Their catalytic activity in the homogeneous phase were evaluated in biomimetic conditions (water, pH 7, 25 deg C), was the same as in the case of pyridoxal.Keywords: racemization / α-aminoester / pyridoxal analogue / multistep synthesis / homogeneous catalysis
- Honnoraty, Anne-Marie,Mion, Louis,Collet, Helene,Teissedre, Robert,Commeyras, Auguste
-
p. 709 - 720
(2007/10/02)
-
- ON THE SYNTHESIS OF β-PHENYLALANINE
-
A practical, economical and efficient two-step synthesis of β-phenylalanine and its methyl ester is reported: ?-phenylserine, 1, is chlorinated to β-chloro-β-phenylalanine, 2; the latter is hydrogenated in the presence of 10percent Pd/C catalyst to give the desired amino acid. β-Phenylalanine is separated (yield based upon β-phenylserine) as the free amino acid 3 (65.3percent yield) or as the hydrochloride 4 (79.8percent yield) or esterified to the methyl ester hydrochloride 5 (78.7percent yield).
- Portelli, Mario
-
p. 215 - 216
(2007/10/02)
-
- Metal Complexes with Biologically Important Ligands, XLV. - Palladium(II) Complexes of Dehydro-α-amino and 2-Imino Acid Esters as Ligands
-
The preparation and spectroscopic data of the complexes trans-Cl2Pd(H2NC(CO2R)=C)2 (1) and trans-Cl2Pd(HN=C(CO2R)-CH)2 (6) and of (+)BF4(-) (2) are reported.The reactions of dehydroamino acid esters R(ROC)-C=C(CO2R)NH2 with Na2PdCl4 give 1-imino-3-ketonato chelate complexes cis- (3), of which one representative (3b) has been characterized by X-ray structure analysis.For comparison the structure of the dehydroamino acid derivative OC(Me)C(CO2Et)=C(CO2Et)NH2 (4) has also been determined.Palladium(II) binds the anion of dehydroarmentomycin via the N,O atoms (8).This coordination is also found with (η5-C5H5)(OC)2Mo and allylglycine (9).
- Wanjek, Herbert,Nagel, Ulrich,Beck, Wolfgang
-
p. 1021 - 1026
(2007/10/02)
-
- Alkylation and Condensation Reactions of N,N-Dibenzylglycine Esters: Synthesis of α-Amino Acid Derivatives
-
Upon deprotonation N,N-dibenzylglycine esters undergo alkylation and condensation reactions at the α-carbon atom with various electrophiles.
- Gray, Brian D.,Jeffs, Peter W.
-
p. 1329 - 1330
(2007/10/02)
-
- CLEAVAGE OF THE N-PChd GROUP FROM PROTECTED AMINO ACIDS AND PEPTIDES BY CATHODIC REDUCTION
-
Amino acids and peptide esters protected by the PChd group can be deprotected cathodically under mild conditions.
- Khalifa, M. Hassen,Rieker, Anton
-
p. 1027 - 1030
(2007/10/02)
-
