1-Propanephosphonic Acid Cyclic Anhydride (T3P) as an Efficient Promoter for the Lossen Rearrangement: Application to the Synthesis of Urea and Carbamate Derivatives
The synthesis of hydroxamic acids starting from carboxylic acids employing 1-propanephosphonic acid cyclic anhydride (T3P) activation is described. Application of ultrasonication accelerates this conversion. Further, the T3P has also been employed to activate the hydroxamates, leading to isocyanates via the Lossenrearrangement. The isocyanates were trapped with suitable nucleophiles to afford the
Application of carbodiimide mediated Lossen rearrangement for the synthesis of α-ureidopeptides and peptidyl ureas employing N-urethane α-amino/peptidyl hydroxamic acids
作者:N. Narendra、Gundala Chennakrishnareddy、Vommina V. Sureshbabu
DOI:10.1039/b905790k
日期:——
Application of the Lossenrearrangement to the synthesis of N-urethane protected α-peptidyl ureas and ureidopeptides is reported. The carbodiimide mediated rearrangement of N-Boc/Z/Fmoc protected α-amino/peptide hydroxamic acids into isocyanates and coupling of the latter with the amino acid esters/peptide esters have been accomplished in a single-pot to obtain good yields of urea products. Synthesis
报道了Lossen重排在N-氨基甲酸酯保护的α-肽基脲和脲肽的合成中的应用。这碳二亚胺N- Boc / Z / Fmoc保护的α-氨基/肽异羟肟酸介导的重排成异氰酸酯,后者与氨基酸酯/肽酯的偶联已在单罐中完成,从而获得了较高的收率。尿素产品。还已经使用相同的方法经由N-保护的天冬氨酸的异羟肟酸酯衍生物合成脲基丙氨酸衍生物。
作者:Patil, Basanagoud S.、Vasanthakumar, Ganga-Ramu、Suresh Babu, Vommina V.
DOI:——
日期:——
Synthesis of Peptidyl Ureas Using <i>p</i>‐Nitrophenyl‐(9‐fluorenylmethoxy Carbonylamino)methyl Carbamate Derivatives
作者:Basanagoud S. Patil、Ganga‐Ramu Vasanthakumar、Vommina V. Suresh Babu
DOI:10.1081/scc-120039483
日期:2004.1.1
An efficient synthesis of p-nitrophenyl-(9-fluorenylmethoxy, carbonylamino) methyl carbamates using isocyanates derived from Fmoc-amino acid azides and p-nitrophenol in presence of an equimolar quantity of N-ethyldiisopropyl amine is described. All the carbamates have been isolated as crystalline solids and are fully characterized. Further, their utility for the synthesis of dipeptidyl ureas has been demonstrated.