104706-58-3

Upstream product

• 24424-99-5 di-tert-butyl dicarbonate 
• 1676-73-9 L-glutamic acid γ-benzyl ester 
• 13574-13-5 Boc-Glu(OBzl)-OH 
• 2592-95-2 benzotriazol-1-ol 

Downstream Products

• 104945-64-4 Boc-Glu(Bzl)-Tyr(Bzl)-OMe 
• 1036718-09-8 (3S)-N-(O-benzyl-N-Boc-L-glutamyl)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid methyl ester 
• 104706-61-8 H-Glu(Bzl)-Asn-Met-Ala-Tyr(Bzl)-OMe trifluoroacetic salt 
• 104945-66-6 H-Glu(Bzl)-Tyr(Bzl)-OMe trifluoroacetic salt 
• 104945-76-8 H-Glu(Bzl)-Asp(Bzl)-Met-Glu(Bzl)-Tyr(Bzl)-OMe trifluoroacetic salt 
• 72086-72-7 N-tert-butoxycarbonylglutamic acid methyl ester 
• 59279-58-2 N^α-tert-butyloxycarbonyl-γ-benzyloxycarbonyl-L-glutamic acid methyl ester 
• 237425-47-7 Boc-L-Glu(OBzl)-L-Lys(ClZ)-OPac 
• 104945-74-6 Boc-Glu(Bzl)-Asp(Bzl)-Met-Glu(Bzl)-Tyr(Bzl)-OMe 

Relevant academic research and scientific papers

Preparation of large macrocyclic peptides using the oxime resin

We exploited a peptide cyclization-cleavage reaction on oxime resin (PCOR) to obtain in one key step large macrocyclic peptides. Herein, we report on the different parameters affecting the cyclization-oligomerization reaction, whether to favor cyclic mono

Synthesis of cationic porphyrin modified amino acids

Derivatives of amino acids bearing a porphyrin moiety on a side chain were synthesized by coupling a porphyrin to a glutamic acid side chain; the utility of these compounds was demonstrated by their use in solid-phase synthesis of a peptide bearing a cati

(3S)-N-(l-Aminoacyl)-1,2,3,4-tetrahydroisoquinolines, a class of novel antithrombotic agents: Synthesis, bioassay, 3D QSAR, and ADME analysis

To increase antithrombotic activity, 3S-tetrahydroisoquinoline-3-carboxylic acid (1) was modified with natural amino acids to form 19 novel dipeptide analogs, 3S-tetrahydroisoquinoline-3-carboxyamino acids (5a-s), targeting the intestinal peptide transport system. In vitro assay of 5a-s indicated that their potencies for inhibiting adenosine diphosphate (ADP), arachidonic acid (AA), platelet-activating factor (PAF), and thrombin (TH)-induced platelet aggregations were higher than that of 1. Additionally, in vivo assay of 5a-s indicated that their potencies for inhibiting thrombogenesis in rats were also higher than that of 1. Among the candidates, 5h with Ser attachment showed the most impressive features for further development. According to molecular field analysis based Cerius2 QSAR module, two equations (r, 0.961 and 0.988) correlating the structures with both in vitro and in vivo activities of 5a-s were established. ADMET calculations predict higher intestinal absorption for compounds 5a-s. Further investigation with 5h as a lead compound is underway.

A 12-porphyrin system: Syntheses of peptide porphyrins with multiple histidines and the aggregation behavior in the presence of hemin

We succeeded in combining multiple-histidine peptides with porphyrins; that is to say, we synthesized three peptide porphyrins consisting of α4- meso-tetrakis(o-aminophenyl)porphyrin, α4-H2TAPP, and amphiphilic peptide, α4(PepA18)(n)(AG)(4-n)-H2TAPP (n = 1, 3, and 4; PepA18 = EEALEKHEKALEKHEKAG), in the liquid phase. These compounds were designed to construct multiple porphyrin systems; in other words, each peptide attached on the H2TAPP was designed to contain two histidines. The stability of the porphyrins, (AG)4-H2TAPP and (AG)1(Boc-AG)3-H2TAPP, as well as the coupling conditions between the porphyrin fragments and the 16-residue peptide, EEALEKHEKALEKHEK, to give α4-(PepA18)(n)(AG)(4-n)-H2TAPP (n = 1, 3, and 4) were studied in detail with respect to the temperature, solvents, coupling reagents, additives, and amines. This search revealed that the combination of DMF/benzotriazol-1-yl-oxytris(pyrrolidino)phosphonium hexafluorophosphate (PyBOP)/N,N-diisopropylethylamine is suitable for the purpose. The search also clarified that it is possible to synthesize α4- (PepA18)4-H2TAPP and α4-(PepA18)3(AG)1-H2TAPP selectively by choosing the coupling additives 1-hydroxy-7-azabenzotriazole (HOAt) and 1- hydroxybenzotriazole (HOBt, respectively. All of the compounds showed 40% helicity in a solution (phospate buffer, pH = 7.0) containing 2,2,2- trifluoroethanol (TFE). The UV-vis and circular-dichroism spectrophotometric titrations of Fe(III) protoporphyrin IX chloride, B, with α4(PepA18)4- ZnTAPP, A, indicated that up to three equivalents of B were incorporated into A in a buffer solution containing 15% TFE. Sedimentation-equilibrium ultracentrifugation experiments showed that A is a dimer in the solution, and that this dimer is transformed to a trimer when B is incorporated into A. These results suggest that A achieves a 12-porphyrin system consisting of different kinds of metalloporphyrin.

Synthesis of a putative subtype specific antigenic heptapeptide from Escherichia coli K88 ad protein fimbriae.

The heptapeptide methyl ester Phe-Asn-Glu-Asn-Met-Ala-Tyr-OMe covering the amino acid sequence of the region 213-219 of Escherichia Coli K88 ad protein fimbriae is synthesized using N alpha-t-butyloxycarbonyl-protection and benzyl groups for side-chain-protection. All condensation reactions are performed in 84-97% yield by preactivation of the protected amino acids by dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotriazole (HOBt), and reaction of the resulting active ester with amine in the presence of 4-methylmorpholine (NMM). A mechanism is proposed for the nitrile formation in the side-chain of activated asparagine, and the suppression of this side-reaction is investigated. The repetitive deprotection is performed in a mixture of trifluoroacetic acid (TFA), phenol and p-cresol to give the TFA salts in virtually quantitatively yields. The final deprotection of the heptapeptide is carried out in a mixture of 25% hydrogen fluoride (HF) and dimethyl sulfide (DMS) in an overall yield of 48%. The serological and conformational properties of the synthetic peptide are under investigation.

Synthesis of a putative antigenic heptapeptide from Escherichia coli K88 ab protein fimbriae.

The heptapeptide Tyr-Arg-Glu-Asp-Met-Glu-Tyr-OMe, spanning region 213-219 of Escherichia coli K88 ab protein fimbriae, was synthesized with an overall yield of 37% using dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotriazole (HOBt) preactivation in all condensation reactions. The C-terminal was protected as the methyl ester. The protection scheme of N alpha-tert-butyloxycarbonyl-(Boc) and benzyl-(Bzl) or benzyloxycarbonyl (Z) groups for side chain protection was found to be orthogonal when a mixture of trifluoroacetic acid (TFA), phenol (PhOH) and p-cresol (CrOH) was used for repetitive deprotection. The final deprotection of Boc-Tyr(Bzl)-Arg(Z2)-Glu(Bzl)-Asp(Bzl)-Met-Glu(Bzl+ ++)-Tyr(Bzl)-OMe (17) was accomplished in 80% yield by prolonged treatment with hydrogen fluoride, dimethyl sulfide, p-cresol and p-thiocresol. The BSA-linked synthetic peptide was used in immunisation experiments on rabbits.