Dolbier HW Solutions 667

Dolbier HW Solutions 667 - tert-butoxycarbonyl (Boc)...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
The reaction shown has been carried out in 100% yield. Alternatively, the benzyloxycarbonyl protecting group may be removed by treatment with hydrogen bromide in acetic acid. This latter route has also been reported in the chemical literature and gives the hydrobromide salt of Phe-Gly ethyl ester in 82% yield. Once the protecting group has been removed, the ethyl ester of Phe-Gly is allowed to react with the p -nitrophenyl ester of Z-protected leucine to form the protected tripeptide. Hydrogenolysis of the Z-protected tripeptide gives Leu-Phe-Gly as its ethyl ester. 27.20 Amino acid residues are added by beginning at the C terminus in the Merri f eld solid-phase approach to peptide synthesis. Thus the synthesis of Phe-Gly requires glycine to be anchored to the solid support. Begin by protecting glycine as its
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: tert-butoxycarbonyl (Boc) derivative. The protected glycine is attached via its carboxylate anion to the solid support. (CH 3 ) 3 COCNHCH 2 CO 2 H O (CH 3 ) 3 COCNHCH 2 COCH 2 resin O O Boc-Protected glycine 1. HO 2 2. ClCH 2 resin (CH 3 ) 3 COCCl (CH 3 ) 3 COCNHCH 2 CO 2 H H 3 NCH 2 CO 2 2 O 1 O 1 tert-Butoxycarbonyl chloride Glycine Boc-Protected glycine Z-protected Leu-Phe-Gly ethyl ester NO 2 1 C 6 H 5 CH 2 OCNHCHCO (CH 3 ) 2 CHCH 2 O O H 2 NCHCNHCH 2 COCH 2 CH 3 O O C 6 H 5 CH 2 p-Nitrophenyl ester of Z-protected leucine Phe-Gly ethyl ester C 6 H 5 CH 2 OCNHCHCNHCHCNHCH 2 COCH 2 CH 3 (CH 3 ) 2 CHCH 2 O O CH 2 C 6 H 5 O O Leu-Phe-Gly ethyl ester H 2 NCHCNHCHCNHCH 2 COCH 2 CH 3 (CH 3 ) 2 CHCH 2 O O CH 2 C 6 H 5 O H 2 , Pd AMINO ACIDS, PEPTIDES, AND PROTEINS. NUCLEIC ACIDS 761...
View Full Document

This note was uploaded on 10/03/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.

Ask a homework question - tutors are online