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1.
A new and efficient method for the synthesis of N(alpha)-Fmoc-/Boc-/Z-beta-amino acids using the two-step Arndt-Eistert approach is described. Fmoc-/Boc-/Z-alpha-Amino acid fluorides were used for the acylation of diazomethane synthesizing Fmoc-/Boc-/Z-alpha-aminodiazoketones as crystalline solids with good yield and purity. They were then converted to the corresponding beta-amino acids using PhCOOAg/dioxane/H2O. 相似文献
2.
Subramanyam J. Tantry Vommina V. Suresh Babu 《International journal of peptide research and therapeutics》2003,10(5):655-662
9-Fluorenylmethyl chloroformate has been demonstrated to be useful reagent for the synthesis of several commonly used activeesters of Fmoc-/Boc-/Z-amino acids. These include pentafluorophenyl, 2,4,5-trichlorophenyl, pentachlorophenyl, p-nitrophenyl, o-nitrophenyl, and succinimidyl esters. The method is simple, rapid and efficient. All the compounds made have been isolated as crystaline solids in good yield and optical purity. They were fully characterized by IR, and 1H NMR. 相似文献
3.
Tantry Subramanyam J. Suresh Babu Vommina V. 《International journal of peptide research and therapeutics》2003,10(5-6):655-662
Summary 9-Fluorenylmethyl chloroformate has been demonstrated to be useful reagent for the synthesis of several commonly used active
esters of Fmoc-/Boc-/Z-amino acids. These include pentafluorophenyl, 2,4,5-trichlorophenyl, pentachlorophenyl,p-nitrophenyl,o-nitrophenyl, and succinimidyl esters. The method is simple, rapid and efficient. All the compounds made have been isolated
as crystaline solids in good yield and optical purity. They were fully characterized by IR, and1H NMR. 相似文献
4.
Gopi Hosahudya N. Suresh Babu Vommina V. 《International journal of peptide research and therapeutics》2000,7(3):165-169
Summary The Wolff rearrangement of α-aminodiazoketones derived fromN
α-urethane protected α-amino acids in the presence of pentafluorophenol catalyzed by silver acetate at low temperature results
in the homologation of Fmoc-/Boc-/Z-α-amino acids to β-amino acids with concomitant formation of the corresponding pentafluorophenyl
esters in good yield and purity. 相似文献
5.
I. McEwen 《Biopolymers》1993,33(6):933-942
The cyclic hexapeptide cyclo[-Pro1-Gly2-Glu3(OBzl) -Pro4-Phes5-Leu6-] ( 1 ) was modeled and synthesized to be used for chiral discrimination studies. Total correlated spectroscopy and nuclear Overhauser effect spectroscopy spectra of the cyclic hexapeptide 1 in CDCl3 showed the presence of three stereoisomers: two dominant stereoisomers 1a and 1b that exchanged chemically with each other, and a minor stereoisomer 1c (4%) that exchanged exclusively with the stereoisomer 1b . Of the two dominant stereoisomers, only 1a interacted specifically with t-butyloxycarbonyl (Boc-) and 9-flourenylmethyloxycarbonyl (Fmoc-) amino acids in CDCl3. The interaction site of la when complexing with the derivatized amino acids was the chain segment Phe5-Leu6. The Phe5 NH and Leu6 NH protons are contiguous and solvent exposed. Their nmr signals shifted strongly downfield with the addition of Boc- or Fmoc- amino acids to the peptide solution. Thus, both NH protons hydrogen bond to the amino acids, forming a two-point hydrogen-bonding complex. The peptide stereoisomer 1b did not interact specifically with the Boc- and Fmoc-amino acids because of the lack of two contiguous and solvent-exposed peptidic NH protons that seem to be needed for specific interactions of the cyclic hexapeptide 1 with the Boc- and Fmoc-amino acids. A clear difference in the interaction of 1a with D - and L -enantiomers of BocTrp and Fmoc-Trp was observed with nmr spectroscopy. Docking models and molecular mechanics calculations together with nmr observations showed that the NH proton of the indole ring of the Boc-L -Trp and the Fmoc-L- Trp hydrogen bonded to the Pro1 carbonyl group. In this three-point hydrogen-bonding complex, the indole ring becomes locked underneath the Leu residue. The nmr signals of all the Leu6 protons (except for Leu NH) shifted strongly upfield owing to the shielding effect of the indole aromatic ring currents. The indole NH of the D -enantiomer did not hydrogen bond to the Pro1 carbonyl group because the formation of such a three-point hydrogen-bonding complex was thermodynamically unfavorable. © 1993 John Wiley & Sons, Inc. 相似文献
6.
A simple, efficient and stereospecific approach for the homologation of urethane-protected alpha-amino acids to beta-amino acids by the Arndt-Eistert method employing Fmoc-/Boc-alpha-amino acid and 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyl-uronium hexafluorophosphate mixture for the acylation of diazomethane synthesizing the key intermediates Fmoc-/Boc-alpha-aminodiazomethanes as crystalline solids is described. 相似文献
7.
The Wolff rearrangement of -aminodiazoketonesderived from N-urethane protected -amino acids in the presence of pentafluorophenol catalyzed by silver acetate at low temperature results in the homologation of Fmoc-/Boc-/Z--amino acids to -amino acids withconcomitant formation of the corresponding pentafluorophenylesters in good yield and purity. 相似文献
8.
Toyama MH Toyama DO Torres VM Pontes GC Farias WR Melo FR Oliveira SC Fagundes FH Diz Filho EB Cavada BS 《The protein journal》2010,29(8):567-571
Low molecular weight fragments of sulfated galactans (Boc-5 and Boc-10) from the red algae Botryocladia occidentalis significantly inhibited Crotalus durissus cascavella sPLA2 enzymatic activity. Equimolar ratios of sPLA2 to Boc-5 or Boc-10 resulted in allosteric inhibition of sPLA2. Under
the conditions tested, we observed that both Boc-5 and Boc-10 strongly decreased edema, myonecrosis, and neurotoxicity induced
by native sPLA2. 相似文献
9.
John W. Perich Nicholas J. Ede Susan Eagle Andrew M. Bray 《Letters in Peptide Science》1999,6(2-3):91-97
astMultipin is a trademark of Chiron Technologies Pty. Ltd., Clayton, Victoria, Australia.The efficiency of various coupling methods for the incorporation of the three monobenzyl phosphorodiester-protected derivatives, Fmoc- Tyr(PO3Bzl,H)-OH, Fmoc-Ser(PO3Bzl,H)-OH and Fmoc-Thr(PO3Bzl,H)-OH, was examined through the test synthesis of Ala-Ser-Gln-Gly-Xxx(PO3H2)-Leu- Glu-Asp-Pro-Ala-NH2 (Xxx = Tyr, Ser, Thr) using the Multipin method of multiple peptide synthesis. The coupling methods examined were (1) PyBrop/DIEA; (2) BOP/HOBt/NMM; (3) BOP/HOBt/DIEA; (4) HBTU/HOBt/DIEA; (5) HATU/HOAt/DIEA; (6) HATU/DIEA; (7) DIC/HOBt; (8) DIC/HOBt/DIEA; (9) DIC/HOAt; (10) DIC/HOAt/DIEA. While all four DIC-based coupling procedures resulted in incomplete incorporation, both the HBTU/HOBt/DIEA and HATU/HOAt/DIEA coupling procedures provided most efficient incorporation of the three Fmoc- Xxx(PO3Bzl,H)-OH derivatives. In the subsequent synthesis of the -helical Tyr(P)-peptide, Glu-Thr-Gly-The-Lys- Ala-Glu-Leu-Leu-Ala-Lys-Tyr(PO3H2)-Glu-Ala-Thr- His-Lys-NH2, analysis of the crude peptide by electrospray MS confirmed that several residue deletions had occurred but that complete incorporation of the Tyr(P)-residue had been accomplished using HBTU/HOBt/DIEA coupling of Fmoc- Tyr(PO3Bzl,H)-OH. 相似文献
10.
Suresh Babu Vommina V. Gopi Hosahudya N. 《International journal of peptide research and therapeutics》1999,6(2-3):173-178
Summary The pentafluorophenyl esters of Boc-/Z-amino acids are used for the preparation of the key intermediates α-aminoacyldiazomethanes
during the homologation of α-amino acid to β-amino acid. Thus, all the Boc-/Z-amino acid diazoketones and the corresponding
β-amino acids were obtained as crystalline solids in satisfactory yields. 相似文献
11.
H Nakase S Murata H Ueno R Hayashi 《Bioscience, biotechnology, and biochemistry》2001,65(11):2465-2471
To clarify the substrate-recognition mechanism of carboxypeptidase Y, Fmoc-(Glu)n Ala-OH (n = 1 to 6), Fmoc-(Glu)n Ala-NH2 (1 to 5), and Fmoc-Lys(Glu)3Ala-NH2 were synthesized, and kinetic parameters for these substrates were measured. Km for Fmoc-peptides significantly decreased as peptide length increased from n = 1 to n = 5 with only slight changes in kcat. Km for Fmoc-(Glu)(5,6)Ala-OH were almost the same as one for protein substrates described previously (Nakase et al., Bull. Chem. Soc. Jpn., 73, 2587-2590). These results show that the enzyme has six subsites (S1' and S1-S5). Each subsite affinity calculated from the Km revealed subsite properties, and from the differences of subsite affinity between pH 6.5 and 5.0, the residues in each subsite were predicted. For Fmoc-peptide amide substrates, the priorities of amidase and carboxamide peptidase activities were dependent on the substrate. It is likely that the interactions between side chains of peptide and subsites compensate for the lack of P1'-S1' interaction, so the amidase activity prevailed for Fmoc-(Glu)(3,5)Ala-NH2. These results suggest that these subsites contribute extensively to substrate recognition rather than a hydrogen bond network. 相似文献
12.
The synthesis of some repetitive sequences of elastin and their simplified analogues, all comprising the structural unit Gly-X-Gly (X = Val, Leu, Ala), is described. In particular, the following peptides and polypeptides were synthesized and characterized: Boc-Gly-Val-Gly-Gly-Leu-OMe, Boc-Gly-Leu-Gly-Gly-Val-OMe, Boc-(Gly-Val-Gly-Gly-Leu)2-OMe, Boc-(Gly-Val-Gly-Gly-Leu)3-OMe, Boc-Gly-Val-Gly-Gly-OEt, Boc-Leu-Gly-Gly-Leu-OMe, Boc-Val-Gly-Gly-Val-OMe, poly(Ala-Gly-Gly), poly(Val-Gly-Gly), and poly(Leu-Gly-Gly). In every case, the synthesis was accomplished by classical procedures in solution, by using the p-nitrophenyl ester method for the polycondensation step, and the mixed anhydride or the azide methods for the coupling steps. 相似文献
13.
The attachment of Fmoc-amino acids onto p- alkoxybenzyl alcohol resins via DCC-DMAP coupling suffers from two different problems: formation of dimers and racemization. The use of N,N-dimethylformamide dineopentyl acetal for the preparation of Fmoc- aminoacyloxybenzyl handles is the basis of a safe and efficient anchoring method that avoids both problems. 相似文献
14.
Chrysostomos Pachatouridis Elias A. Couladouros Vassilios P. Papageorgiou Maria Liakopoulou-Kyriakides 《Letters in Peptide Science》1998,5(4):259-262
The synthesis of derivatives of aminoquinones with N-protected amino acids is reported here. 2-Amino-1,4-benzoquinone and 2-amino-1,4-naphthoquinone, prepared by the azide method in yields of 60 and 95% respectively, were coupled with N-Boc-protected amino acids including glycine, serine, proline and tyrosine, to give the correspondening derivatives. N,N'-Diisopropylcarbodiimide/1-hydroxybenzotriazole or N,N'-dicyclohexylcarbodiimide/HOBt used as coupling reagents provided the expected products in satisfactory yields and purities as supported by TLC, HPLC and spectral analysis. 相似文献
15.
Pachatouridis Chrysostomos Couladouros Elias A. Papageorgiou Vassilios P. Liakopoulou-Kyriakides Maria 《International journal of peptide research and therapeutics》1998,5(4):259-262
Summary The synthesis of derivatives of aminoquinones with N-protected amino acids is reported here. 2-Amino-1,4-benzoquinone and
2-amino-1,4-naphthoquinone, prepared by the azide method in yields of 60 and 95% respectively, were coupled with N-Boc-protected
amino acids including glycine, serine, proline and tyrosine, to give the correspondening derivatives.N, N′-Diisopropylcarbodiimide/1-hydroxybenzotriazole orN, N′-dicyclohexylcarbodiimide/HOBt used as coupling reagents provided the expected products in satisfactory yields and purities
as supported by TLC, HPLC and spectral analysis. 相似文献
16.
Sample peptides Boc-Leu4-Aib-Leu4-OBzl and Boc-(Leu4-Aib)2-OBzl, were crystallized by the solvent-evaporation method. Both crystals are monoclinic, with space group of P2(1) and Z = 2. The cell parameters are a = 16.580 (7), b = 21.105 (7), c = 11.583 (4) A, and beta = 104.90 (3) degrees (Boc-Leu4-Aib-Leu4-OBzl), and a = 15.247 (9), b = 19.04 (1), c = 16.311 (9) A, and beta = 117.10 (1) degrees [Boc-(Leu4-Aib)2-OBzl]. Crystal structures were solved by the direct method and refined to R values of 0.096 (the former peptide) and 0.112 (the latter). Peptide backbones fold into a right-handed alpha-helix, except for the C-terminal Aib residue in Boc-(Leu4-Aib)2-OBzl. Both peptide molecules are stabilized by six (the former) or seven (the latter) intramolecular (5----1) hydrogen bonds, and arranged in the head-to-tail fashion, which makes an infinite column. In this column, one (the former) or two (the latter) intermolecular hydrogen bonds link the neighboring molecules. In the case of Boc-Leu4-Aib-Leu4-OBzl, the solvent molecule N,N-dimethylformamide was found in the difference Fourier map. There was a hydrogen bond between peptide and solvent molecule. Along the lateral direction, only hydrophobic contacts were observed between adjacent peptide molecules. 相似文献
17.
Insa Flechsler Annette G. Beck-Sickinger Holger Stephan Robert Sheppard Günther Jung 《Journal of peptide science》1995,1(3):191-200
Cleavage and kinetic studies have been carried out using commercially obtained H-Tyr(tBu)-5-(4′-aminomethyl-3′,5′-dimethoxyphenoxy)valeric acid-TentaGelS (H-Tyr(tBu)-4-ADPV-TentaGelS) and H-Tyr (tBu)-4-ADPV-Ala-aminomethyl-resin (H-Tyr(tBu)-4-ADPV-AM-resin) prepared from commercially available resin and loaded with commercially available Fmoc-4-ADPV-OH amide anchor. Cleavage with pure trifluoroacetic acid (TFA) gave the intermediate H-Tyr-4-ADPV-NH2, which was then degraded to H-Tyr-NH2, and cleavage with TFA/dichloromethane (1:9) yielded H-Tyr-4-ADPV-NH2 which could be isolated in preparative amounts. Cleavage reactions with 15N-labelled H-Ala-4-ADPV-[15N]-Gly-AM-resin yielded the intermediate H-Ala-4-ADPV-NH2, which contained no 15N as demonstrated by 1H-NMR. The analysis of the commercial Fmoc-4-ADPV-OH amide anchor showed the presence of Fmoc-4-ADPV-4-ADPV-OH as an impurity in high amounts. This dimeric anchor molecule is the cause of formation of the anchor-linked peptide intermediate obtained during the cleavage from the resin. The particularly high acid-lability of the amide bond between the two ADPV moieties was utilized to synthesize sidechain and C-terminally 4-ADPV protected pentagastrin on a double-anchor resin, and to cleave it using 5% trifluoroacetic acid in dichloromethane. This method may offer a new way for the synthesis of protected peptide amides with improved solubility to be used in fragment condensation. 相似文献
18.
Laura Biondi Fernando Filira Marina Gobbo Raniero Rocchi 《Journal of peptide science》2002,8(2):80-92
Stepwise solution syntheses of the homo-oligomers Boc-(Asn)n-NHCH3 (n = 1-5; I1-5), Boc-[[GlcNAc(Ac)3beta]Asn]n-NHCH3 (n = 1-8; II1-8), and Boc-[(GlcNAcbeta)Asn]n-NHCH3 (n = 1-8; III1-8) are described. Members of the series III were obtained by deacetylation of the corresponding members of the series II. The conformational preferences of the N-protected homo-peptides of the three series were investigated by spectroscopic techniques. 1H-NMR measurements were carried out in various solvents; the CD spectra were recorded in water, aqueous SDS and TFE. The poor solubility of the oligomers of the three series prevented FT-IR measurements in solution. NMR and IR measurements indicate the existence of unordered structures containing some gamma-turns in the carbohydrate-free oligomers and the presence of beta-turns in the glycosylated oligopeptides, whether acetylated or not. The CD spectra do not indicate the presence of organized structures. The sugar moieties apparently do not have a structure-inducing effect on the asparagine homo-oligomer main chain. 相似文献
19.
The synthesis of C-protected esters of Boc-/Z-alpha,alpha-dialkylamino acids is accomplished by using alkyl/aryl chloroformate in presence of DMAP as a catalyst. The reaction proceeds through mixed carboxylic carbonic anhydride, which was monitored by IR. The reaction was clean and complete in about 2 hr. All the esters prepared have been obtained in good yield and are fully characterized. 相似文献
20.
The type and distribution of the β-helixes occurring in chloroform solutions of Boc-(L-Val-D-Val)6-OMe and Boc-(L-Val-D-Val)8-OMe have been studied by using 1H-nmr techniques. Right- and left-handed ↑↓β4.4-helices and left-handed β5.6-helices occur with the dodecapeptide. β4.4-Helices of opposite handedness occur also with the hexadecapeptide, but ↑↓β5.6-helices could not be detected with this oligomer. At equilibrium, at 25°C, the double helix of the dodecapeptide is only moderately populated. These results indicate that increasing the chain length has a destabilizing effect on the ↑↓β5.6-helices of D ,L -alternating oligovalines in chloroform solution. 相似文献