N-Fmoc-protected(alpha-dipeptidoyl)benzotriazoles for efficient solid-phase peptide synthesis by segment condensation

Area of Science:

• Organic Chemistry
• Peptide Chemistry
• Synthetic Chemistry

Background:

• Solid-phase peptide synthesis (SPPS) is a crucial technique in biochemistry and drug discovery.
• Developing efficient methods for synthesizing peptide segments is essential for creating complex peptides.
• N-Fmoc protection is a widely used strategy in peptide synthesis.

Purpose of the Study:

• To develop a novel method for synthesizing N-Fmoc-protected alpha-dipeptides and their benzotriazole derivatives.
• To investigate the utility of these intermediates in solid-phase peptide segment condensation.
• To optimize the synthesis of longer peptides using microwave irradiation.

Main Methods:

• Synthesis of N-Fmoc-protected(alpha-aminoacyl)benzotriazoles (1a-d).
• Conversion of these intermediates to N-Fmoc-protected(alpha-dipeptidoyl)benzotriazoles (3a-f).
• Microwave-assisted solid-phase peptide segment condensation using 3a-f to yield peptides of varying lengths.

Main Results:

• High yields (77-89%) were achieved for the synthesis of chiral N-Fmoc-protected alpha-dipeptides (2a-f).
• N-Fmoc-protected(alpha-dipeptidoyl)benzotriazoles (3a-f) were obtained with an average yield of 71%.
• Solid-phase synthesis using 3a-f under microwave irradiation successfully produced peptides from tri- to heptapeptide length with yields ranging from 20-68%.

Conclusions:

• The developed method provides an efficient route to N-Fmoc-protected alpha-dipeptide and dipeptidoyl benzotriazole intermediates.
• Microwave-assisted solid-phase peptide segment condensation is a viable strategy for constructing longer peptides from these building blocks.
• This approach offers a valuable tool for the synthesis of complex peptides in organic and medicinal chemistry.