113266-24-3

Upstream product

• 1170-76-9 Z-Gly-(L)-Phe 
• 6306-52-1 L-valine methylester hydrochloride 
• 63-91-2 L-phenylalanine 
• 54885-66-4 Z-Gly-D-Phe-OH 
• 4070-48-8 L-Valine methyl ester 
• 1138-80-3 N-(Benzyloxycarbonyl)glycine 

Relevant academic research and scientific papers

Ethyl 2-Cyano-2-(hydroxyimino)acetate (Oxyma): An efficient and convenient additive used with tetramethylfluoroformamidinium hexafluorophosphate (TFFH) to replace 1-hydroxybenzotriazole (HOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) during peptide synthesis

The appropriateness of ethyl 2-cyano-2-(hydroxyimino)acetate (Oxyma) as a substitute for benzotriazole-based additives, for use in the TFFH approach for peptide synthesis, is discussed in terms of its capacity to control racemization, its coupling efficiency in difficult couplings either for stepwise or segment coupling in solution- and solid-phase coupling. In addition, Boc-based solution-phase peptide synthesis and its stability in the presence of growing peptide chains were studied. Oxyma displayed remarkable results in terms of racemization depression together with impressive coupling efficiency in both solution- and solid-phase synthesis. Furthermore, Oxyma suggests a lower risk of explosion than HOBt and HOAt.

PS-IIDQ: a supported coupling reagent for efficient and general amide bond formation

Polystyrene-IIDQ, a polymer-supported coupling reagent, was synthesized in three steps from Merrifield resin in 86% overall conversion. This reagent efficiently coupled carboxylic acids to amines in good yields and high purities, required no pre-activation step, and was tolerant of the order of reagent addition. PS-IIDQ was observed to be more efficient than polymer-supported carbodiimides (PS-EDC and PS-DCC) and gave higher yields than HATU for general amide bond formation, including the coupling of anilines and hindered substrates. When evaluated with five carboxylic acids and nine amines (including anilines and secondary amines) PS-IIDQ gave an average isolated yield of 73%.

S-(2-Pyrimidinyl)- and S-(2-(4,6-dimethylpyrimidinyl))-1,1,3,3- tetramethylthiouronium hexafluorophosphates: Novel reagents for in situ peptide coupling

Two new reagents for in situ peptide coupling based on the 2-mercaptopyrimidine core have been developed. The readily prepared thiouronium salts were found to promote both peptide and segment coupling efficiently with low racemization/epimerization levels

2-Mercaptopyridine-1-oxide-based peptide coupling reagents

The thiouronium salts S-(1-oxido-2-pyridinyl)-1,1,3,3-tetramethylthiouronium hexafluorophosphate (HOTT) and tetrafluoroborate (TOTT), and S-(1-oxido-2-pyridinyl)-1,3-dimethyl-1,3-trimethylenethiouronium hexafluorophosphate (HODT) and tetrafluoroborate (TODT), prepared from 2-mercaptopyridine-1-oxide and 1,1,3,3-tetramethylurea (TMU) or 1,3-dimethylpropyleneurea (DMPU), have been employed as reagents in solution and solid-phase peptide coupling chemistry. Furthermore, 2-mercaptopyridine-1-oxide has been employed as racemization-reducing additive combined with the new thiouronium salts and other frequently used peptide coupling reagents such as DCC or TBTU.

Polymer-bound N-hydroxysuccinimide as a solid-supported additive for DCC-mediated peptide synthesis

Polymer-supported N-hydroxysuccinimide (P-HOSu) has been prepared from a styrene/maleic anhydride co-polymer and used as an easily removable activating and racemization-reducing additive for the peptide coupling of amino acid derivatives using DCC.

New and highly efficient immonium type peptide coupling reagents: Synthesis, mechanism and application

A series of novel immonium type coupling reagents BOMI, BDMP, BPMP, DOMP, SOMP, FOMP and AOMP were designed and synthesized. It was shown that most of these reagents were more efficient in peptide synthesis than conventional methods due to the advantages

1-Ethyl 2-halopyridinium salts, highly efficient coupling reagents for hindered peptide synthesis both in solution and the solid-phase

1-Ethyl-2-halopyridinium salts, BEP, FEP, BEPH and FEPH, were synthesized and proved to be very effective for the synthesis of hindered peptides containing N-methylated or C(α),C(α)-dialkylated amino acid residues. HPLC monitoring of model reactions indicated that these pyridinium salts demonstrated higher reactivities, lower racemization than the commonly used halogenated uronium and phosphonium salts. The efficiency of these pyridinium type coupling reagents was further proved by the synthesis of a series of hindered oligopeptides and active esters with good yields and convenient workup. The 8-11 tetrapeptide fragment of Cyclosporin A (CsA) and the pentapeptide moiety of Dolastatin 15 were also successfully synthesized using these pyridinium salts. The efficiency of these pyridinium type coupling reagents for SPPS was also demonstrated by the solid-phase synthesis of the extremely hindered 8-11 peptide segment of CsA and the linear undecapeptide of CsO. The mechanism of the pyridinium salt mediated coupling reactions was also studied by 1H NMR, IR and HPLC. It was proposed that the major reactive intermediates were the corresponding acyl halide and acyloxypyridinium salts of the N-protected amino acid or peptide. (C) 2000 Elsevier Science Ltd.

Total synthesis of cyclosporin O both in solution and in the solid phase using novel thiazolium-, immonium-, and pyridinium-type coupling reagents: BEMT, BDMP, and BEP

Cyclosporin O (1), an extensively N-methylated immunosuppressive cyclic undecapeptide isolated from Tolypocladium inflatum Gams, was synthesized in 20-23% overall yield via 4 + 7 segment condensation and cyclization by the combined utilization of novel thiazolium- and immonium-type peptide coupling reagents 2-bromo-3-ethyl-4-methyl thiazolium tetrafluoroborate (BEMT) and 5- (1H-benzotriazol-1-yloxy)-3,4-dihydro-1-methyl 2H-pyrrolium hexachloroantimonate (BDMP) as well as compound 2-bromo-1-ethyl pyridinium tetrafluoroborate (BEP). BEMT and BEP, which have been proven to be very efficient for the coupling of peptide segments containing N-alkylated amino acid residues with respect to the fast reaction speed, low racemization, and high yields, were used to construct hindered amide bonds in CsO with the addition of HOAt, whereas the most efficient HOBt-derived immonium type reagent, BDMP, was used to perform the coupling of coded amino acids in CsO. Thus, the highly hindered protected 8-11 tetrapeptide 25 was successfully synthesized using BEMT in 65% yield, and the 1-7 heptapeptide 21 was obtained in 52-55% yield by the rationally combined utilization of BDMP, BEMT, and BEP. The synthesis of the linear undecapeptide 27 of CsO in the solid phase using BEMT and BEP was accomplished for the further evaluation of the effectiveness of these reagents.

Efficient amounts of additives for peptide coupling mediated by a water-soluble carbodiimide in aqueous media

The optimal amounts of HOBt, HOSu, and HONb for enhancement of peptide coupling mediated by EDC in aqueous media were found to be less than equimolar against the C-component or the carbodiimide. A combination of EDC and 0.1 equimolar amount of HOBt was sh

A new water-compatible dehydrating agent DPTF

The dehydration of a carboxylic acid and an amine to form an amide linkage was performed by the use of a new water-compatible dehydrating agent, 2,2-dichloro-5-(2-phenylethyl)-4-(trimethylsilyl)-3-furanone (DPTF). The application of this new agent to the peptide bond formation is also described.