61543-21-3Relevant articles and documents
Polymer-supported O-benzyl and O-allylisoureas: Convenient preparation and use in ester synthesis from carboxylic acids
Crosignani, Stefano,White, Peter D.,Steinauer, Rene,Linclau, Bruno
, p. 853 - 856 (2003)
Polymer-supported O-methyl, O-benzyl, and O-allyl-isoureas were prepared by copper(II)-catalyzed reaction of polymer-supported carbodiimide with the corresponding alcohols. These polymer-supported reagents were successfully employed to convert a series of carboxylic acids to methyl, benzyl, or allyl esters, in good yields. The products were obtained with high purity (>95% by NMR) after a simple resin filtration-solvent evaporation sequence.
Use of 'click chemistry' for the synthesis of tetrazole-containing analogues of the neuroprotective agent glycyl-L-prolyl-L-glutamic acid
Hung, Kuo-Yuan,Harris, Paul W. R.,Brimble, Margaret A.
scheme or table, p. 1233 - 1236 (2009/09/06)
Tetrazole-containing analogues of glycyl-L-prolyl-L-glutamic acid (GPE) were prepared by coupling of Cbz-glycyl-L-proline with tetrazole-containing glutamic acids followed by hydrogenation of the resultant tripeptide. Synthesis of the tetrazole-containing glutamic acids involved 1,3-dipolar cycloaddition of sodium azide to nitrile derivatives of the corresponding glutamic acids. Georg Thieme Verlag Stuttgart.
Synthetic approaches to peptides containing the l-Gln-l-Val-D(S)-Dmt motif
Suaifan, Ghadeer A.R.Y.,Arafat, Tawfiq,Threadgill, Michael D.
, p. 3474 - 3488 (2008/02/05)
The pseudoprolines S-Dmo (5,5-dimethyl-4-oxaproline) and R-Dmt (5,5-dimethyl-4-thiaproline) have been used to study the effects of forcing a fully cis conformation in peptides. Synthesis of peptides containing these (which have the same configuration as l-Pro) is straightforward. However, synthesis of peptides containing S-Dmt is difficult, owing to the rapid cyclisation of l-Aaa-S-Dmt amides and esters to form the corresponding diketopiperazines (DKP); thus the intermediacy of l-Aaa-S-Dmt amides and esters must be avoided in the synthetic sequence. Peptides containing the l-Gln-l-Val-D(S)-Dmt motif are particularly difficult, owing to the insolubility of coupling partners containing Gln. Introduction of Gln as N-Boc-pyroglutamate overcame the latter difficulty and the dipeptide active ester BocPygValOC6F5 coupled in good yield with S-DmtOH. BocPygVal-S- DmtNH(CH2)2C6H4NO2 was converted quantitatively to BocGlnVal-S-DmtNH(CH2)2C6H4NO2 with ammonia, demonstrating the utility of this approach. Two peptide derivatives (CbzSerLysLeuGlnVal-S-DmtNH(CH2)2C6H4NO2 and CbzSerSerLysLeuGlnVal-S- DmtNH(CH2)2C6H4NO2) were assembled, using these new methods of coupling a dipeptide acid active ester with S-DmtOH and introduction of Gln as Pyg, followed by conventional peptide couplings. The presence of the Val caused these peptides to be cleaved very slowly by prostate-specific antigen (PSA) at Leu ↓ Gln, rather than the expected Gln ↓ Val.
