Synthesis Of Dipeptides Research Articles

Enhancement of the activity of papain in mixed reverse micellar systems in the presence of Tween80

An enhancement in the activity of papain (EC 3.4.22.2) was described in mixed reverse micellar systems containing Tween80 compared with those without Tween80. By the use of these media, the hydrolytic and synthesis activities of papain were investigated in detail, respectively for the hydrolysis of N-α-benzoyl-L-arginine-p-nitroaniline (BNPNA) and the synthesis of the dipeptide Z-Gly-L-PheOMe (ZGPM). The reaction medium conditions (W0, pH and Tween80 concentration) were optimized for both the hydrolytic and synthesis reactions. The results showed a pronounced increase in the papain activity when a moderate amount of Tween80 was added into sodium di-2-ethylhexylsulfosuccinate (AOT) or tetradecyltrimethylammonium bromide (TTAB) reverse micelles, either in the yield of dipeptide synthesis or in the initial rate of BNPNA hydrolysis. In addition, a mechanism to explain the enhancement of enzymatic activity was proposed according to the change of the optimal parameters in the mixed and non-mixed reverse micellar systems, which is associated with the environmental polarity surrounding the solubilised enzyme molecules. © 2001 Society of Chemical Industry

Stability Properties of Thermoresponsive Poly(N-Isopropylacrylamide)-Trypsin Conjugates

Trypsin was covalently coupled to poly(N-isopropylacrylamide) (pNIPAAm), a thermoresponsive polymer, through reactive groups of N-acryloxysuccinimide (NAS), which were incorporated into the polymer and the enzyme, respectively, prior to immobilization. Higher activity was retained for the enzyme that was coupled to the preformed copolymer of NIPAAm-NAS (conjugate I) as compared to conjugate II prepared by the other method. The conjugated trypsin was found to be more resistant to heat treatment than the free enzyme. Just the physical presence of the polymer had no significant influence on the thermal stability of the free trypsin. The activity loss in the conjugated enzymes during repeated precipitation/dissolution cycles was more due to incomplete recovery than to inactivation by temperature during the precipitation step. Conjugate I exhibited significant retention of activity after storage in acetonitrile and DMF, and was also used for dipeptide synthesis in acetonitrile.

ChemInform Abstract: Synthesis and Conformation of Gly-Gly Dipeptides Constrained with Phenylalanine-Like Aminocaproic Acid Linkers.

[structure: see text] The constraint of dipeptides with linkers derived from 6-aminocaproic acid (Aca) is a useful means of constructing a beta-turn peptidomimetic. The extension of this concept to the mimicry of a tripeptide entails the incorporation of a side chain moiety on either end of the Aca chain. The synthesis and conformational analysis of two exemplary compounds is discussed.

The carbenoid approach to peptide synthesis.

A different approach to the synthesis of dipeptides is described based on the formation of the NHCHR1CONH-CHR2CO bond by carbenoid N-H insertion, rather than the formation of the peptide bond itself. Thus decomposition of triethyl diazophosphonoacetate catalysed by rhodium(II) acetate in the presence of N-protected amino acid amides 8 gives the phosphonates 9. Subsequent Wadsworth-Emmons reaction of 9 with aldehydes in the presence of DBU gives dehydro dipeptides 10. The reaction has been extended to a simple two-step procedure, without the isolation of the intermediate phosphonate, for conversion of a range of amino acid amides 11 into dehydro dipeptides 12 and to an N-methylamide 11 h, and for conversion of a dipeptide to tripeptide (13-->14). Direct conversion, by using methyl diazophenylacetate, of amino acid amides to phenylglycine-containing dipeptides 19 proceeds in good chemical yield, but with poor diastereoselectivity.

Synthesis of Cyclic Dipeptides by Ring-Closing Metathesis

Several cyclic dipeptides (4a−g and 9a−c) have been synthesized by “amide-to-amide” cyclization of 2a−g and 8a−c, respectively, by means of ring-closing metathesis employing the Grubbs ruthenium catalyst. The influence of additives as well as the length of the amide substituent were studied. Best yields were obtained by cyclization in solution with either lithium fluoroacetate or α,α-dichlorotoluene as an additive.

Solid-phase synthesis of muramyl dipeptide (mdp) derivatives using a multipin method

Solid-phase synthetic method of muramyl dipeptide derivatives is reported. A diverse library of muramyl dipeptides could be potentially synthesized by acylation, reductive alkylation, sulfonamide formation, urea formation, N-alkylation, amine addition, or component Ugi reactions based on this method for drug screening.

Synthesis and conformation of Gly-Gly dipeptides constrained with phenylalanine-like aminocaproic acid linkers.

[structure: see text] The constraint of dipeptides with linkers derived from 6-aminocaproic acid (Aca) is a useful means of constructing a beta-turn peptidomimetic. The extension of this concept to the mimicry of a tripeptide entails the incorporation of a side chain moiety on either end of the Aca chain. The synthesis and conformational analysis of two exemplary compounds is discussed.

Synthesis of highly fluorinated dipeptide building blocks

A new approach to the synthesis of dipeptides containing up to three trifluoromethyl groups has been developed. The method is based on a [4+1]-cycloaddition reaction of hexafluoroacetone or methyl 3,3,3-trifluoropyruvate derived N-acylimines and α-amino acid isocyanides. Acidic hydrolysis of the cycloadducts gives the trifluoromethylated dipeptides in good yields.

Synthesis and conformational analysis of a dimerising eight-membered lactam dipeptide

Download options Please wait... Supplementary files Crystal structure data TXT (26K) Article information DOI https://doi.org/10.1039/B003789N Article type Paper Submitted 11 May 2000 Accepted 21 Jun 2000 First published 15 Aug 2000 Download Citation J. Chem. Soc., Perkin Trans. 1, 2000, 2943-2956 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Synthesis and conformational analysis of a dimerising eight-membered lactam dipeptide S. Derrer, J. E. Davies and A. B. Holmes, J. Chem. Soc., Perkin Trans. 1, 2000, 2943 DOI: 10.1039/B003789N To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Sam Derrer John E. Davies Andrew B. Holmes

Novel α-hydroxyethyl-polystyrene, α-chloroethyl-polystyrene and α-amino-oxyethyl-polystyrene linkers on the multipin™ solid support for solid-phase organic synthesis

A simple method for the generation of three novel linkers, alpha-hydroxyethyl-polystyrene, alpha-chloroethyl-polystyrene and alpha-amino-oxyethyl-polystyrene on Multipin supports (SynPhase Crowns) has been developed. Applications of these linkers have been successfully demonstrated for solid-phase synthesis of dipeptide, oxime, and hydroxamic acid compounds in good yields and purities.

Novel α‐hydroxyethyl‐polystyrene, α‐chloroethyl‐polystyrene and α‐amino‐oxyethyl‐polystyrene linkers on the multipin™ solid support for solid‐phase organic synthesis

A simple method for the generation of three novel linkers, α-hydroxyethyl-polystyrene, α-chloroethyl-polystyrene and α-amino-oxyethyl-polystyrene on Multipin supports (SynPhase™ Crowns) has been developed. Applications of these linkers have been successfully demonstrated for solid-phase synthesis of dipeptide, oxime, and hydroxamic acid compounds in good yields and purities. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng (Comb Chem) 71:91–93, 2000/2001.

Synthesis and Conformation of a Novel Dipeptide Derived from a γ-Amino Acid with Norbornane Skeleton

An enantiomerically pure γ-amino acid 9 with norbornane skeleton was synthesized from the norbornene dicarboxylic acid 5. NOE studies and AM1 calculations on the protected dipeptide 10 derived from this amino acid revealed that the conformation of the peptide backbone is determined by an intramolecular hydrogen bond between the two subunits.

Coupling Reagent Dependent Regioselectivity in the Synthesis of Lysine Dipeptides

Participation of either the Nℇ or Nα of l-methyl lysinate (2) in peptide bond formation could be selectively achieved by the use of either isobutyl chloroformate (method A) or N,N-bis(2-oxo-3-oxazolidinyl) phosphinic chloride (BOP-Cl) (method B), respectively. The amidation performed according to method A gives high yields of the dipeptides 3a-e, irrespective of the amino acids used. In method B, Nα amidation is highly preferred especially with bulky amino acids, yielding 4a, 4c and 4e. The less bulky 4b and 4d gave 4.5 and 20 regioselection Nα/Nℇ amidation ratios. A mechanistical rationalization for these selectivities is discussed.

Synthesis of New Seven-Membered Ring Cyclic Dipeptides From Functionalized β-Amino Acids

A short synthesis of new, functionalized seven-membered ring cyclic dipeptides is described. After the coupling of N-protected β-amino acids to N-substituted α-amino tert-butyl esters, the protective groups of the terminal functions were removed and the cyclization took place diastereoselectively in the presence of the coupling agent BOP. Amide substitution was found to be effective in promoting the cyclization of linear dipeptides.

Synthesis of non proteinogenic dipeptides by asymmetric hydrogenation.

N-Boc protected non-proteinogenic dipeptides with D,L- and L,L-configuration were prepared by catalytic asymmetric hydrogenation of the corresponding dehydrophenylalanyl-(L)-phenylalanine derivatives. The configuration of the new stereogenic centre depends first of all on the catalyst configuration and is less influenced by the substrate configuration. Diastereomeric excesses in the range of 80-96% de could be increased up to 99% by recrystallization. Analytical data of selected new compounds are given.

Solid-Supported Chloro[1,3,5]triazine. A Versatile New Synthetic Auxiliary for the Synthesis of Amide Libraries

2,4,6-Trichloro[1,3,5]triazine was loaded on different types of NH2-functionalized resins to give a new supported reagent. The best results, in term of yields products, were obtained using the chlorotriazine linked to a polystyrene−poly(ethylene glycol) resin. This reagent was employed for the solution-phase synthesis of different amides and dipeptides.

A short synthesis of bicyclic dipeptides corresponding to Xxx-L-Pro Xxx-D-Pro having constrained trans-proline amides.

[formula: see text] A short synthesis that generates two isomeric bicyclic dipeptides having constrained, trans-proline amide bonds has been developed. One of these bicyclic dipeptides corresponds to an Xxx-L-Pro dipeptide (4), while the other isomer corresponds to an Xxx-D-Pro dipeptide (5). The two isomers are readily distinguished by their 1H NMR spectra.

Di-tert-butyl Dicarbonate: A Novel Reagent for the Efficient Synthesis of Dipeptides under Mild Conditions.

Di-tert-butyl Dicarbonate: A Novel Reagent for the Efficient Synthesis of Dipeptides under Mild Conditions.

An efficient synthesis of bicyclic β-turn dipeptides via a photochemical key step

A novel synthetic route to bicyclic β-turn dipeptides (BTD) is described. It starts with L-β-benzoylalanine 1, which is N-protected and coupled with proline esters yielding the dipeptides 3. Upon irradiation 3a-c undergo a cyclization to the indolizinones 4 in a highly stereoselective manner. 4a and 4c were converted into the N-protected BTD derivatives suited for the peptide synthesis. The absolute configuration of products 4 and 5 were unambiguously elucidated from NOE results.

A simple method for the generation of chloromethyl polystyrene on the Multipin™ solid support

A novel route for the chloromethylation of polystyrene grafted Multipin supports (Synphase™ Crowns) has been developed. Aminomethylated polystyrene was converted into chloromethylated polystyrene via a simple diazotisation reaction. The modified graft polymer was assessed by solid phase synthesis of a model dipeptide.