Recently, therapeutically active benzofuranones, such as 1 and 2 (Scheme 1), have emerged as an important class of anti-T cells. cruzi agent. 1 QSAR studies determined the correlation between the activity of benzyltriphenylphosphonium chloride phenylvinyl substituents and N-oxide groups. 2 The synthetic route that has been considered for the production of the phenylvinyl moiety is shown in Scheme 1 . Based on the various methods reported for the Wittig reaction, we chose the mild conditions promoted by crown ether catalysis in the Bodens method. 3
Continuing this research, we attempted to prepare and evaluate new anti-T proteins. Some analogs of cruzi agents 1 and 2, where R is an electron-donating substituent. Our first approach involved the preparation of compound 6 (Scheme 2). To synthesize this derivative, we planned the synthesis method shown in Scheme 2, in which we used the conventional synthesis of the phosphonium salt 5, which involves halide nucleophilic substitution with triphenylphosphine.
The molecular diagram of 7 shows the labeling of non-H atoms and their displacement ellipsoids at the 50% probability level. Hydrogen atoms are stereochemically positioned and refined through the riding model. The methyl H atom position was optimized by treating it as a rigid group, allowing rotation around the corresponding C-N bond during the refining process. The two half-molecules are related to each other by the twofold axis of the crystal along the perpendicular direction. 7
The generation of compound 7 may be a result of the presence of good leaving groups and nucleophilic moieties in the same structure in 3 and possibly in 4. This combination promotes the formation of intermediate 8 , which can be reacted as shown in Scheme 4 . Assuming these processes, acidic media that reduce the nucleophilicity of the amine could avoid the formation of byproduct 7 . This option uses an acidic medium and offers the possibility to prepare phosphonium salt from phosphonium salt in a one-pot method
ISSN 1424-6376 Page 130 ©ARKAT
Comprehensive paper ARKIVOC 2006 (xi) 128-136
the corresponding alcohol and avoid isolation of the halide intermediate. Another method has been reported to use Ph3P·HBr salts for direct extraction from ethanol, but this process requires high thermal activation and expensive reagents. 8-10
