60644-13-5

Upstream product

• 3082-75-5 L-Alanine ethyl ester 
• 1161-13-3 N-Cbz-L-Phe 
• 84758-92-9 ((S)-1-Benzyl-2-dibenzoylamino-2-oxo-ethyl)-carbamic acid benzyl ester 
• 1115-59-9 (S)-alanine ethyl ester hydrochloride 
• 87072-42-2 Z-L-phenylalanine DCHA salt 
• 63-91-2 L-phenylalanine 
• 3397-32-8 N-(benzyloxycarbonyl)-phenylalanine-N-hydroxysuccinimide ester 
• 501-53-1 benzyl chloroformate 
• 84758-88-3 (S)-2-Benzyloxycarbonylamino-3-phenyl-propionic acid 2-oxo-1,2-diphenyl-ethyl ester 
• 84758-90-7 2-<1-amino>-2-phenylethyl>-4,5-diphenyloxazole 
• 64-17-5 ethanol 
• 3338-39-4 N-benzyloxycarbonyl-L-phenylalanyl-L-alanine 

Downstream Products

• 97800-70-9 1-Benzyl-3-[(S)-1-((S)-1-carbamoyl-ethylcarbamoyl)-2-phenyl-ethylcarbamoyl]-pyridinium; bromide 
• 97800-89-0 (S)-2-{(S)-3-Phenyl-2-[(pyridine-3-carbonyl)-amino]-propionylamino}-propionic acid ethyl ester 
• 97800-91-4 N-[(S)-1-((S)-1-Carbamoyl-ethylcarbamoyl)-2-phenyl-ethyl]-nicotinamide 
• 97859-64-8 (S)-2-((S)-2-Amino-3-phenyl-propionylamino)-propionic acid ethyl ester; hydrobromide 

Relevant academic research and scientific papers

Tandem deprotection/coupling for peptide synthesis in water at room temperature

A tandem deprotection/coupling sequence is reported for solution-phase peptide synthesis in water under micellar catalysis conditions using the designer surfactant TPGS-750-M. Cbz deprotection followed by peptide coupling in the presence of COMU and 2,6-lutidine afforded polypeptides containing up to 10 amino acid residues. A broad scope characterizes this new technology. No epimerization has been detected. The associated E Factors, as a measure of "greenness" and known to be extremely high for peptide couplings, have been reduced to less than 10 due to the step-economy and minimal amounts of organic solvent needed for product extraction.

Heterogeneous catalysis with nickel-on-graphite (Ni/Cg): Reduction of aryl tosylates and mesylates

(Chemical Equation Presented) How would you reduce an aryl OH group? Traditionally, a palladium catalyst, a mild source of hydride, and a triflate derivative are used in solution. A more modern alternative is presented that is not only economical but heterogeneous as well. Nickel-on-graphite (Ni/C g) is introduced as a very inexpensive catalyst that reduces aryl tosylates and mesylates with excellent functional group tolerance.

Papain-catalyzed esterification of N(α)-protected amino acids and dipeptides with ethanol in different organic systems

The papain-catalyzed esterification of N(α)-protected amino acids and dipeptides with ethanol in mostly hydrophobic organic solvent systems containing low amounts of water has been investigated. The influence of various parameters, such as the amount of added water, reaction time, temperature and pH of added buffer, on the yield of ester was studied first on the model substrate Z-Ala. The optimized reaction conditions were then used for esterification of a series of N(α)-protected amino acids and dipeptides.

KINETICS OF THE ALKALINE HYDROLYSIS OF SEVERAL N-BENZYLOXYCARBONYLDIPEPTIDE METHYL AND ETHYL ESTERS

The reaction rates of the alkaline hydrolysis of synthesized N-protected dipeptide methyl and ethyl esters were studied systematically.From the kinetic data the energies of activation, the pre-exponential factors and the reference values at 40 deg C were calculated.The rate of hydrolysis shows to be strongly dependent on the C-terminal amino acid in the sequence Gly >> Ala/Met/Phe > Leu >> Val/Pro.Surprisingly the N-terminal amino acid also exerts an effect, but in a different sequence.N-Terminal Phe in particular shows a relative accelerating effect.Remarkable is the significantly faster ester hydrolysis of glycine containing dipeptide ethyl esters in ethanol/water compared to the corresponding methyl esters in methanol/water.

Investigations on Quaternary Pyridinium Salts, XVIII. - Note on Synthetic Cyclopeptides with 1,4-Dihydronicotinamide Moiety

Quaternary salts of the amides of N-nicotinoyldipeptides form under the influence of base dimers with 20-membered rings, cyclopeptide-like substances with two 1,4-dihydronicotinamide moieties (8).

2-HALOVINYL ARYL SULFONES: NEW COUPLING REAGENTS FOR CARBOXAMIDE FORMATION

E-2-Chlorovinyl p-nitrophenyl sulfone 6 and 2-bromo-2-trifluoromethylvinyl phenyl sulfone 7a reacted with carboxylic acids in the presence of a molar equiv of Et3N affording the corresponding 2-acyloxyvinyl sulfones 8, 11, 17, 18, 22, 25, 28 and 29.The latter, on treatment with amines, gave amides 9, 13, 19, 23 and 26 and peptides 30 and 32.These reagents 6 and 7a were also used for the formation of N-methylanilides 13d, 13e, 19d, 23 and 26.Particularly, 6 was successfully used for synthesis of a macrocyclic lactam 23 involving a N-methylanilide moiety.The amidation reac tions proceeded under essentially neutral conditions.Therefore, base-sensitive β-hydroxycarboxy-N-methylanilides such as 26, whose structural unit was involved in maytansine 5, could be prepared by the present method.The reagent 6 was also effective for the preparation of peptides such as Val-N-MeVal derivatives (e.g.32), which were difficult to prepare by other methods.

THE OXAZOLE-TRIAMIDE REARRANGEMENT. APPLICATION TO PEPTIDE SYNTHESIS

The carboxyl group of a N-acylated amino acid may be protected by conversion to an oxazole derivative which, on photooxygenation, regenerates the carboxyl group in activated (triamide) form for peptide synthesis.