cas 3401-36-3, Z-ALA-OSU | Articles data

Articles about 3401-36-3Total 27 be found

Article title
Article abstract
Author
Journal number and time
Download

Ynamide-Mediated Thiopeptide Synthesis
Exploration of the full potential of thioamide substitution as a tool in the chemical biology of peptides and proteins has been hampered by insufficient synthetic strategies for the site-specific introduction of a thioamide bond into a peptide backbone. A novel ynamide-mediated two-step strategy for thiopeptide bond formation with readily available monothiocarboxylic acids as thioacyl donors is described. The α-thioacyloxyenamide intermediates formed from the ynamides and monothiocarboxylic acids can be purified, characterized, and stored. The balance between their activity and stability enables them to act as effective thioacylating reagents to afford thiopeptide bonds under mild reaction conditions. Amino acid functional groups such as OH, CONH2, and indole NH groups need not be protected during thiopeptide synthesis. The modular nature of this strategy enables the site-specific incorporation of a thioamide bond into peptide backbones in both solution and the solid phase.
Yang, Jinhua,Wang, Changliu,Xu, Silin,Zhao, Junfeng
supporting information
p. 1382 - 1386
(2019/01/08)

Mechanistic implications of the enantioselective addition of alkylzinc reagents to aldehydes catalyzed by nickel complexes with α-amino amide ligands
The enantioselective alkylation of aldehydes catalysed by nickel(ii)-complexes derived from α-amino amides was studied by means of density functional theory (DFT) and ONIOM (B3LYP:UFF) calculations. A mechanism was proposed in order to investigate the origin of enantioselectivity. The chirality-determining step for the alkylation was the formation of the intermediate complexes with the involvement of a 5/4/4-fused tricyclic transition state. The predominant products predicted theoretically were of (S)-configuration, in good agreement with experimental observations. The scope of the reaction was examined and high yields and enantioselectivities were observed for the enantioselective addition of Et2Zn and Me2Zn to aromatic and aliphatic aldehydes.
Escorihuela, Jorge,Burguete, M. Isabel,Ujaque, Gregori,Lledós, Agustí,Luis, Santiago V.
supporting information
p. 11125 - 11136
(2016/12/07)

An efficient procedure for the preparation of carboxamides and peptides using in situ generated N-succinimidyl active esters
-
Han, Ki-Jong,Kim, Misoo
p. 370 - 375
(2014/08/05)

Synthetic tripeptides as alternate substrates of murein peptide ligase (Mpl)
Murein peptide ligase (Mpl) is an enzyme found in Gram-negative bacteria. It catalyses the addition of tripeptide l-Ala-γ-d-Glu-meso-diaminopimelate to nucleotide precursor UDP-N-acetylmuramic acid during the recycling of peptidoglycan. Although not essential, this enzyme represents an interesting target for antibacterial compounds through the synthesis of alternate substrates whose incorporation into peptidoglycan might be deleterious for the bacterial cell. Therefore, we have synthesised 10 tripeptides l-Ala-γ-d-Glu-Xaa in which Xaa represents amino acids different from diaminopimelic acid. Tripeptide with Xaa = ε-d-Lys proved to be an excellent substrate of Escherichia coli Mpl in vitro. Tripeptides with Xaa = p-amino- or p-nitro-l-phenylalanine were poor substrates, while tripeptides with Xaa = d- or l-2-aminopimelate, dl-2-aminoheptanoic acid, l-Glu, l-norleucine, l-norvaline, l-2-aminobutyric acid or l-Ala were not substrates at all. Although a good Mpl substrate, the d-Lys-containing tripeptide was devoid of antibacterial activity against E. coli, presumably owing to poor uptake.
Hervé, Mireille,Kova?, Andreja,Cardoso, Cécile,Patin, Delphine,Brus, Boris,Barreteau, Hélène,Mengin-Lecreulx, Dominique,Gobec, Stanislav,Blanot, Didier
p. 1120 - 1126
(2013/07/05)

C2 symmetrical nickel complexes derived from α-amino amides as efficient catalysts for the enantioselective addition of dialkylzinc reagents to aldehydes
A series of C2 symmetrical 1:2 Ni:L complexes derived from α-amino amides were studied for the enantioselective addition of dialkylzinc reagents to aldehydes. Different structural elements on the ligands seem to play an important role in determining the observed enantioselectivity. Through optimization of structure and reaction conditions, the best ligand provided secondary alcohols in excellent yields (up to 98%) and enantioselectivity of up to 99% ee for (R)-enantiomer. A transition state model has been proposed to explain the observed enantioselectivities based on computational calculations at the DFT level. Very interestingly, calculations suggest a coordination model of the aldehyde to the metal complex through association of a lone pair of the carbonyl oxygen to the hydrogen atom of an amino group.
Escorihuela, Jorge,Altava, Belen,Burguete, M. Isabel,Luis, Santiago V.
p. 551 - 558
(2013/07/27)

Efficient access to enantiopure γ4-amino acids with proteinogenic side-chains and structural investigation of γ4- asn and γ4-ser in hybrid peptide helices
Hybrid peptides composed of α- and β-amino acids have recently emerged as new class of peptide foldamers. Comparatively, γ- and hybrid γ-peptides composed of γ4-amino acids are less studied than their β-counterparts. However, recent investigations reveal that γ4-amino acids have a higher propensity to fold into ordered helical structures. As amino acid side-chain functional groups play a crucial role in the biological context, the objective of this study was to investigate efficient synthesis of γ4-residues with functional proteinogenic side-chains and their structural analysis in hybrid-peptide sequences. Here, the efficient and enantiopure synthesis of various N- and C-terminal free-γ4-residues, starting from the benzyl esters (COOBzl) of N-Cbz-protected (E)-α,β-unsaturated γ-amino acids through multiple hydrogenolysis and double-bond reduction in a single-pot catalytic hydrogenation is reported. The crystal conformations of eight unprotected γ4-amino acids (γ4-Val, γ4-Leu, γ4-Ile, γ4-Thr(OtBu), γ4-Tyr, γ4-Asp(OtBu), γ4- Glu(OtBu), and γ-Aib) reveals that these amino acids adopted a helix favoring gauche conformations along the central Cγi￡ Cβ bond. To study the behavior of γ4- residues with functional side chains in peptide sequences, two short hybrid γ-peptides P1 (Ac-Aib-γ4-Asn-Aib-γ4-Leu- Aib-γ4-Leu-CONH2) and P2 (Ac-Aib- γ4-Ser-Aib-γ4-Val-Aib-γ4-Val- CONH2) were designed, synthesized on solid phase, and their 12-helical conformation in single crystals were studied. Remarkably, the γ4-Asn residue in P1 facilitates the tetrameric helical aggregations through interhelical H bonding between the side-chain amide groups. Furthermore, the hydroxyl side-chain of γ4-Ser in P2 is involved in the interhelical H bonding with the backbone amide group. In addition, the analysis of 87 γ4-residues in peptide single-crystals reveal that the γ4-residues in 12-helices are more ordered as compared with the 10/12- and 12/14-helices. Copyright
Jadhav, Sandip V.,Misra, Rajkumar,Singh, Sumeet K.,Gopi, Hosahudya N.
supporting information
p. 16256 - 16262
(2013/12/04)

Synthesis of potent water-soluble tissue transglutaminase inhibitors
Dipeptide-based sulfonium peptidylmethylketones derived from 6-diazo-5-oxo-l-norleucine (DON) have been investigated as potential water-soluble inhibitors of extracellular transglutaminase. The lead compounds were prepared in four steps and exhibited pote
Griffin, Martin,Mongeot, Alexandre,Collighan, Russell,Saint, Robert E.,Jones, Richard A.,Coutts, Ian G.C.,Rathbone, Daniel L.
scheme or table
p. 5559 - 5562
(2009/05/30)

Enantioselective nickel-catalyzed conjugate addition of dialkylzinc to chalcones using chiral α-amino amides
A series of α-amino amides derived from natural amino acids (alanine, valine, phenylalanine, isoleucine, and phenylglycine) have been synthesized and fully characterized. Their Ni(II) complexes prepared from Ni(acac)2 catalyze the enantioselective conjugate addition of diethylzinc to chalcones in high yields and in good enantioselectivities (up to 84%). The side chain of the amino acid and the substituents in the amide nitrogen govern the enantioselectivity of the catalytic process.
Escorihuela, Jorge,Burguete, M. Isabel,Luis, Santiago V.
scheme or table
p. 6885 - 6888
(2009/04/07)

Coordination chemistry of phosphanyl amino acids: Solid state and solution structures of neutral and cationic rhodium complexes
Copper phosphide or arsenide complexes, [Cu(EPh2)(neo)] (E = P, As, neo = 2,9-dimethyl-1,10-phenanthroline; trivial name: neocuprine) react selectively with the N-protected brominated serine derivatives, 2-(S)-(alkoxycarbonylamino)-3-bromomethy
Meyer, Christian,Scherer, Markus,Schoenberg, Hartmut,Rueegger, Heinz,Loss, Sandra,Gramlich, Volker,Gruetzmacher, Hansjoerg
p. 137 - 148
(2007/10/03)

A simple synthesis and determination of alkali metal binding selectivities of chiral macrocyclic tetraamides derived from L-alanine
Chiral α,ω-diamines react under high-pressure conditions (10 kbar) with α,ω-dicarboxylates to give chiral cyclic tetraamides having C2-symmetry. The alkali metal (Li+, Na+, K+, Rb+, and Cs+
Szczepanska,Tarnowski,Jurczak
p. 1909 - 1917
(2007/10/03)

Self-assembly of small peptidomimetic cyclophanes
The self-assembly of a series of small peptidomimetic cyclophanes in organic solvents was studied. X-ray diffraction, NMR spectroscopy, and molecular modelling were used to understand the structural features of these self-assembling compounds both at the molecular and supramolecular level. The factors that could influence the formation of gels rather than crystals were studied and a model for the arrangement of molecules in the gel was proposed. Furthermore, scanning electron microscopy revealed that in some cases these compounds undergo a transcription of chirality when going from organogelator to helicoidal gel fibres.
Becerril, Jorge,Burguete, M. Isabel,Escuder, Beatriu,Galindo, Francisco,Gavara, Raquel,Miravet, Juan F.,Luis, Santiago V.,Peris, Gabriel
p. 3879 - 3890
(2007/10/03)

O-succinimidyl-1,3-dimethyl-1,3-trimethyleneuronium salts as efficient reagents in active ester synthesis
The new uronium salts O-succinimidyl-1,3-dimethyl-1,3-trimethyleneuronium hexafluorophosphate (HSDU) and tetrafluoroborate (TSDU) have been prepared from 1,3-dimethylpropyleneurea (DMPU) and employed in the synthesis of N-hydroxysuccinimide-derived active esters. High yields were obtained at room temperature in short reaction times and no racemization was observed.
Bailén, Miguel A,Chinchilla, Rafael,Dodsworth, David J,Nájera, Carmen
p. 1661 - 1664
(2007/10/03)

Synthetic, three-dimensionally stabilized polypeptide mimics of HIV
Methods for synthesizing three-dimensional stabilized peptides which mimic the three-dimensional configuration of the active site of a natural, biologically active protein are carried out by (1) noting the three-dimensional configuration of the active site of a known biologically active protein (2) noting the amino acid sequence and the hydrogen bonds existing between amino acids which hydrogen bonds are capable of maintaining the three-dimensional configuration of the active site and (3) producing a synthetic three-dimensional peptide to mimic the structure of the active site. The synthetic peptide is synthesized so as to have the same or a similar amino acid sequence to the amino acid sequence of the active site of the biologically active polypeptide but with the stabilizing hydrogen bonds being replaced by a bridging divalent radical selected from the group of --(N)--C(CH3)=N(H+)--CH2 --(N)--; --(N)--C(CH3)=N(H+)--CH2 --CH2 --(N)--; and --(N)--N=CH--CH2 --CH2 --CH2 --(C)--. The stabilized three-dimensional peptide obtained is then isolated from the reaction mixture. The invention makes it possible to produce a wide range of biologically active compounds which have stable three-dimensional structures which allow the compounds to be used to obtain, for example, stabilized three-dimensional peptides which mimic the antigenic sites on viral envelopes which are useful as vaccines.
-
(2008/06/13)

Synthesis of N-alkoxycarbonyl-3-substituted tetramic acids and functionalized enols via C-acylation reactions of active methylene compounds with N-hydroxysuccinimide esters of N-alkoxycarbonyl-α-amino acids
The N-hydroxysuccinimide esters of N-alkoxycarbonyl-α-amino acids react with active methylene compounds (malonic and acyl acetic esters), under basic conditions, to produce N-alkoxycarbonyl-3-substituted tetramic acids 7-17; in the case of the N-hydroxysuccinimide ester of L-alanine, the corresponding optically active tetramic acids 15 and 16 are obtained. In addition, the C-acylation reactions of cyanoacetic esters furnishes the functionalized enols 18-23 in very good yields. Spectral data and physical characteristics for all compounds are reported.
Detsi, Anastasia,Micha-Screttas, Maria,Igglessi-Markopoulou, Olga
p. 2443 - 2449
(2007/10/03)

Cathepsin B-sensitive dipeptide prodrugs. 1. A model study of structural requirements for efficient release of doxorubicin
A series of lysosomal protease-sensitive peptides attached to doxorubicin (DOX) was prepared as model substrates for internalizing anticancer immunoconjugates and potential antimetastasis prodrugs. Rates of cathepsin B-mediated release of free drug was measured for each, and human plasma stabilities for representative examples.
Dubowchik, Gene M.,Firestone, Raymond A.
p. 3343 - 3346
(2007/10/03)

Synthesis and stereoselective C-C bond-forming reactions of peptide aldehydes
The reaction of the activated form of N-protected amino acids 6 and 10 or peptides 14 and 18 with chiral amino alcohols derived from the corresponding α-amino acids affords peptide alcohols which can be oxidized under Swern conditions to produce the corresponding peptide aldehydes 9, 12, 16 and 20. The rational synthesis of diastereomeric di- and tripeptide aldehydes, e.g., (S,S)- or (R,S)-dipeptides as well as (S,S,S)- or (R,S,S)-tripeptides is possible by proper choice of the respective building blocks [(S)- versus (R)-amino acids]. The compounds can be prepared without any undesired α-epimerization. However, the long-term configurational stability depends upon the configuration at the remote stereogenic center, e.g., (R,S)-dipeptide aldehydes epimerize faster than the (S,S) diastereomers. Di- and tripeptide aldehydes 9, 12, 16 and 20 undergo chelation-controlled Grignardtype additions with Me2CuLi that involve little or no undesired α-epimerization. The (S,S)- and (R,S)-dipeptide aldehydes 9 and 12 undergo chelation-controlled pinacol reactions induced by the low-valent vanadium reagent [V2Cl3(THF)6]2[Zn2Cl 6]. The major products in both cases are the corresponding C2-symmetric diols 33 and 36, respectively, which are of interest as potential HIV-protease inhibitors. The degree of stereoselectivity is significantly higher in the case of the (S,S)-dipeptide aldehydes relative to the (R,S) analogs, an observation which can be explained on the basis of three-point binding of the peptides to vanadium. VCH Verlagsgesellschaft mbH, 1996.
Reetz, Manfred T.,Griebenow, Nils
p. 335 - 348
(2007/10/03)

In the search for new anticancer drugs. 27. Synthesis and comparison of anticancer activity in vivo of amino acids, carbohydrates, and carbohydrate- amino acid conjugates containing the [N'-(2-chloroethyl)-N'- nitrosoamino]carbonyl group
The [N'-(2-chloroethyl)-N'-nitrosoamino]carbonyl [(2- chloroethyl)nitrosocarbamoyl, CNC] moiety containing compounds CNC- glycinamide 2d, CNC-amino acid derivatives 7a-d, and carbohydrate-CNC-amino acid conjugates 13, 18, 22, 23, 27, and 28 were synthesized and evaluated in vivo for their anticancer activities against the murine lymphocytic leukemia P388 using the National Cancer Institute (NCI) protocol. The most active compound was 2d with a 520% increase in life span (%ILS) and 6/6 survivors after 60 days. The CNC-amino acid analogs 7a-d possessed high to moderate activities with maximum %ILS values of 270, 174, 141 and 132, respectively. Among the carbohydrate-CNC-amino acid derivatives the α-methyl glycoside derivatives 22 and 23 were most active with maximum %ILS values of 277 and 137, respectively, followed by the hemiacetal carbohydrate analogs 13 and 18 with %ILS values of 93 and 149, respectively, and the tetra-O-acetyl derivatives 27 and 28 with %ILS of 110 and 111, respectively. Compounds 7b, 18, 23 and 28 were then tested in vivo against the murine lymphoid leukemia L1210 using the NCI protocol. In this case, the hemiacetal type carbohydrate- CNC-amino analog 18 had the highest activity with a maximum %ILS value of 477 and 4/6 survivors on day 60, followed by 7b (275% ILS), 23 (152% ILS) and 28 (106% ILS). The lipophilicities of all CNC compounds were determined by the partition coefficient using the UV method. A correlation of %ILS values with log P values indicated, in general, an increase in cytotoxicity with a decrease in hydrophilicity for the carbohydrate-CNC-amino acid conjugates 13, 18, 22, 23 and the clinical drugs streptozotocin (1e), chlorozotocin (1f), and cymerin (1g).
Sosnovsky,Gnewuch
p. 989 - 998
(2007/10/02)

Structure-Activity Study of 5-Substituted 1-Carbobenzoxy-2-iminohydantoins as Potential Anticonvulsant Agents
On the basis of our previous findings, a series of 5-substituted 2-iminohydantoins has been synthesized and tested for anticonvulsant activity to better understand the SAR of 2-iminohydantoins.Among the compounds tested, (S)-(+)-1-carbobenzoxy-2-iminohydantoin analogs with ethyl (6)-, n-propyl (7a)-, isopropyl (8)-, allyl (9)-, and sec-butyl (11)-substituted groups at the C5 of the iminohydanotin ring provided the best activities against the MES test with ED50 values in the range of 52-74 mg/kg.All of the above compounds except 8 also showed activity against the scMET test with ED50 values in the range of 141-223 mg/kg.All significantly active compounds (1, 6, 7a, 8, 9, and 11) possesed aliphatic hydrocarbon side chains of two- to three-carbon lengths at the C5 position.All of the compounds with no or minimal activity had either shorter or longer side chains.The compounds substituted at the C5 position by aryl groups, arylalkyl groups, or alkyl and arylalkyl groups containing heteroatoms also showed no activity against the MES and scMET tests.The results suggested that the C5 side chain with the correct stereochemistry in 2-iminohydantoins provides optimal anticonvulsant activity when the side chains are aliphatic hydrocarbons with a lenght, ignoring branchingg, of two to three carbons.
Sun, Zhong-Yue,Kwon, Chul-Hoon,Wurpel, John N. D.
p. 2841 - 2845
(2007/10/02)

In the search for new anticancer drugs. XXIV: Synthesis and anticancer activity of amino acids and dipeptides containing the 2-chloroethyl- and [N'- (2-chloroethyl)-N'-nitroso]-aminocarbonyl groups
A series of L,L-(42, 44, 46, and 60) and D,D-(43, 45, 47, and 61) dipeptide derivatives composed of phenylglycine, phenylalanine, homophenylalanine, and valine and containing a 2-chloroethylamino group at the C-terminus and an N'-(2-chloroethyl)-N'-nitrosoaminocarbonyl group at the N-terminus of the dipeptides were prepared. The dipeptide derivatives (42- 47, 60, and 61) were first evaluated in vivo for their anticancer activities against the murine lymphocytic leukemia P388. Compounds 42, 44, 46, and 60 possessed activities ranging from 46 to 111 percent increase in life span (%ILS), whereas 43 was marginal (%ILS = 31) and 45, 47, and 61 were inactive. In general, the L,L-series exhibited low to good activity (%ILS = 46-111), whereas the corresponding D,D-series, except for 43 (%ILS = 31), was devoid of activity. The analogously structured monoamino acid derivatives of L- alanine (74), L-phenylalanine (75), and L-aspartic acid (76) exhibited higher activity against P388 than the dipeptide derivatives (i.e., 481, 297, and 481 %ILS, respectively). The more active representatives of dipeptides (i.e., 42, 44, and 60) and the amino acids derivatives 74-76 were then tested in vivo against the murine lymphoid leukemia L1210. Compounds 42, 44, and 60 exhibited either low or marginal activity (i.e., the %ILS values were 46, 31, and 26, respectively). Compounds 74, 75, and 76 possessed low to moderate activity, as evidenced by the %ILS values of 56, 48, and 64, respectively. The %ILS parameters obtained against the P388 and L1210 tumor lines were correlated with the corresponding lipophilicities, and there is a trend towards higher activity with concomitant decrease in hydrophobicity.
Sosnovsky,Prakash,Rao
p. 1 - 10
(2007/10/02)

Synthesis of Cyclopropanated and Branched-Chain Pyranosides via Carbohydrate Triflates
Approaches to the cyclopropanated pyranosides benzyl 3,4-("exo"-cyano)methano-3,4-dideoxy-β-L-arabinopyranoside (5) and benzyl 3,4-("exo"-cyano)methano-3,4-dideoxy-α-D-arabinopyranoside (6) and the branched-chain epoxy sugars benzyl-2,3-anhydro-4-(tert-butoxycarbonyl)methyl-4-deoxy-β-L-lyxopyranoside (7) and benzyl 2,3-anhydro-4-(tert-butoxycarbonyl)-methyl-4-deoxy-α-D-lyxopyranoside (8) by displacement of the triflate group with carbanions are described.Preparation of biologically important sugars bearing peptides has been demonstrated by reduction of 5 and 6 to benzyl 3,3-("exo"-aminomethyl)methano-3,4-dideoxy-β-L-arabinopyranoside (9) and benzyl 3,4-("exo"-aminomethyl)methano-3,4-dideoxy-α-D-arabinopyranoside (10) and the coupling of the resulting amines with protected L-alanine.
Fatima, Ayjaz,Zaman, Fakhar,Shekhani, Mohammed Saleh,Malik, Abdul,Voelter, Wolfgang
p. 389 - 392
(2007/10/02)

Novel Preparation of N-Protected Amino Acid Active Esters Using 1,2,2,2-Tetrachloroethyl Carbonates
1,2,2,2-Tetrachloroethyl chloroformate reacts with substituted phenols or N-hydroxy imides to yield crystalline and stable mixed aryl or oximido tetrachloroethyl carbonates.When allowed to react with an N-protected amino acid derivative, these compounds proved to be efficient for the syntheses of the corresponding active esters.A series of active esters including p-nitrophenol, trichlorophenol, pentafluorophenol, and N-hydroxysuccinimide derivatives were prepared by this new procedure.
Jaoudai, Mahmoud,Martinez, Jean,Castro, Bertrand
p. 2364 - 2367
(2007/10/02)

Peptide synthesis in aqueous solution. I. Application of p-dialkyl-sulfoniophenols as a water-soluble coupling reagent
-
Kouge,Koizumi,Okai,Kato
p. 2409 - 2418
(2007/10/02)

THE SYNTHESIS OF AMIDES, ESTERS, AND THIOESTERS
Diethyl 2-(3-oxo-2,3-dihydro-1,2-benzisosulfonazolyl)phosphonate is a highly reactive condensing agent, which provides good yield route to amides, esters, and thioesters from a variety of amines, active hydroxylamines, and thiols and acids.
Miyake, Muneharu,Kirisawa, Makoto,Tokutake, Norio
p. 123 - 126
(2007/10/02)

SYNTHESIS OF N-HYDROXYSUCCINIMIDE ESTERS OF N-PROTECTED AMINO ACIDS AND PEPTIDES USING N,N'-DISUCCINIMIDYL SULFITE
-
Il'ina, A. V.,Davidovich, Yu. A.,Rogozhin, S. V.,Moiseenkov, A. M.
p. 1067 - 1070
(2007/10/02)

A Convenient Synthesis of Peptide Using Oxallates
The equimolar reactions of N-protected amino acids , amino acids or amino acid esters with oxallates (1a-1e) having active ester groups in the presence of pyridine in acetonitrile afforded the corresponding dipeptides via active esters in good yields.
Takeda, Kazuyoshi,Sawada, Izumi,Suzuki, Akira,Ogura, Haruo
p. 4451 - 4454
(2007/10/02)

A novel reagent (N_succinimidyl diphenylphosphate) for synthesis of active ester and peptide
N-succinimidyl diphenylphosphate (SDPP) was prepared. This reagent was useful for the preparation of active esters and peptides in stead of dicyclohexylcarbodiimide.
Ogura, Haruo,Nagai, Sachiko,Takeda, Kazuyoshi
p. 1467 - 1468
(2007/10/02)

Dichlorotris(dimethylamino)phosphorane as Dehydration Reagent for the Preparation of Activated (-ONp, -OPcp, -NSu)Esters of N-Protected Multifunctional Amino Acids
Dichlorotris(dimethylamino)phosphorane (5) is an excellent reagent for the preparation of the activated esters of N-protected amino acids 7-9.Besides 4-nitrophenyl-, pentachlorophenyl-, and N-hydroxysuccinimide esters of various N-protected amino acids, in the presence of HOBt benzyloxycarbonyl-threonine N-hydroxysuccinimide ester was obtained for the first time.
Appel, Rolf,Glaesel, Ursula
p. 3511 - 3516
(2007/10/02)