A Direct Synthesis of 3,5‐Dibromo‐<i>O</i>‐methyl‐<scp>L</scp>‐tyrosine
作者:Jeremy Stewart、Isamu Katsuyama、Hesham Fahmy、Frank R. Fronczek、Jordan K. Zjawiony
DOI:10.1081/scc-120027296
日期:2004.12.31
Abstract A simple and efficient synthesis of 3,5‐dibromo‐O‐methyl‐L‐tyrosine is described by directbromination of commercial O‐methyl‐L‐tyrosine with bromine in aqueous hydrochloric acid. MO calculations are presented to explain a difference in the degree of substitution of O‐methyl‐L‐tyrosine in different solvents.
Total synthesis of the natural isoprenylcysteine carboxyl methyltransferase inhibitor spermatinamine
作者:José García、Raquel Pereira、Angel R. de Lera
DOI:10.1016/j.tetlet.2009.06.087
日期:2009.9
The first total synthesis of spermatinamine, an inhibitor of isoprenylcysteinecarboxylmethyltransferase (Icmt) with a bromotyrosine–spermine–bromotyrosine dimeric structure is described.
Purpurealidin I (1) showed no selectivity but its simplified pyridin-2-yl derivative (36) had the best improvement in selectivity (Selectivity index 4.1). This shows that the marine bromotyrosines are promising scaffolds for developing cytotoxic agents and the full understanding of the elements of their SAR and improving the selectivity requires further optimization of simplified bromotyrosine derivatives.
Syntheses of pseudoceramines A–D and a new synthesis of spermatinamine, bromotyrosine natural products from marine sponges
作者:J. Mikael Hillgren、Christopher T. Öberg、Mikael Elofsson
DOI:10.1039/c1ob06722b
日期:——
Herein we report the total syntheses of pseudoceramine A-D (2â5) and spermatinamine (1) isolated from the marine sponge Pseudoceratina sp. Direct acyl substitution of α-hydroxyiminoesters with amine nucleophiles was developed as a key transformation. The synthetic compounds confirm the reported structures and importantly gives access to non-symmetrical spermine based natural products carrying two different bromotyrosine building blocks. Our new synthesis of spermatinamine is two steps shorter and more efficient than the previously reported sequence.