3350-43-4

Upstream product

• 152972-10-6 Z-AIB-(L)-Phe-O-(t-Bu) 
• 63-91-2 L-phenylalanine 
• 15030-75-8 Z-Aib-ONp 
• 501-53-1 benzyl chloroformate 
• 2577-90-4 methyl (2S)-2-amino-3-phenylpropanoate 
• 16874-17-2 L-phenylalanine tert-butyl ester 
• 15030-72-5 Z-Aib-OH 
• 3350-41-2 2-(benzyloxycarbonylamino)isobutyryl-L-phenylalanine methyl ester 

Downstream Products

• 152972-11-7 Z-AIB-(L)-Phe-(D)-Pro-OMe 
• 3350-44-5 [1-((S)-4-benzyl-5-oxo-4,5-dihydro-oxazol-2-yl)-1-methyl-ethyl]-carbamic acid benzyl ester 
• 152972-13-9 (R)-1-{(S)-2-[2-((S)-2-Benzyloxycarbonylamino-5-chloro-pentanoylamino)-2-methyl-propionylamino]-3-phenyl-propionyl}-pyrrolidine-2-carboxylic acid pentafluorophenyl ester 

Relevant academic research and scientific papers

α-N-Protected dipeptide acids: A simple and efficient synthesis via the easily accessible mixed anhydride method using free amino acids in DMSO and tetrabutylammonium hydroxide

The importance of dipeptides both in medicinal and pharmacological fields is well documented and many efforts have been made to find simple and efficient methods for their synthesis. For this reason, we have investigated the synthesis of α-N-protected dipeptide acids by reacting the easily accessible mixed anhydride of α-N-protected amino acids with free amino acids under different reaction conditions. The combination of TBA-OH and DMSO has been found to be the best to overcome the low solubility of amino acids in organic solvents. Under these experimental conditions, the homogeneous phase condensation reaction occurs rapidly and without detectable epimerization. The present method is also applicable to side-chain unprotected Tyr, Trp, Glu, and Asp but not Lys. This latter residue is able to engage two molecules of mixed anhydride giving the corresponding isotripeptide. Moreover, the applicability of this protocol for the synthesis of tri- and tetrapeptides has been tested. This approach reduces the need for protecting groups, is cost effective, scalable, and yields dipeptide acids that can be used as building blocks in the synthesis of larger peptides.

Efficient peptide coupling involving sterically hindered amino acids

(Chemical Equation Presented) Hindered amino acids have been introduced into peptide chains by coupling N-(Cbz- and Fmoc-α-aminoacyl) benzotriazoles with amino acids, wherein at least one of the components was sterically hindered, to provide compounds 3a-e, (3c +3 c′), 5a-d, (5a + 5a′), 6a-c, (6b + 6b′), 8a-c, 9a-e, 10a-d, and (10a + 10a′) in isolated yields of 41-95% with complete retention of chirality as evidenced by NMR and HPLC analysis. The benzotriazole activation methodology is a new route for the synthesis of sterically hindered peptides. (Note: compound numbers written within brackets represent diastereomeric mixtures or racemates; compound numbers without brackets represent enantiomers.)

Stereospecific synthesis of chlamydocin

A stereospecific synthesis of the cyclic tetrapeptide chlamydocin via free radical homologation from a (S)-2-amino-5-iodopentanoic acid containing cyclic tetrapeptide is described.