AbstractCopper oxide nanoparticles that are supported on graphene oxide as a catalytic system have been utilized for ligand‐free and solvent‐free CS cross‐coupling reactions with weak bases such as triethylamine. Symmetrical/unsymmetrical aryl sulfides have been synthesized by the coupling of different aryl halides with aromatic as well as aliphatic sulfides. Surprisingly, aryl chlorides also well reacted with different types of sulfides in the presence of dimethyl sulfoxide and cesium carbonate. Besides, this catalytic system is suitable for the synthesis of phenothiazines via cascade CS and CN cross‐coupling of ortho‐dihalides and ortho‐aminobenzothiazoles. In addition, this alternative approach is extremely useful for the synthesis of a variety of symmetrical diaryl sulfides by using thiourea as a sulfur source that is devoid of the foul smell of thiols. Indeed, the calculated E‐factor value of our present protocol is 2.52. Furthermore, this protocol is particularly attractive as an environmentally benign and practical method for the synthesis of different aryl sulfides. Moreover, the heterogeneous catalytic system described in this process represents not only a greener approach but retains its significant activity for up to six catalytic cycles.magnified image
The present invention relates to novel phalloidin derivatives and their fluorescent dye conjugates. These new compounds may be used in studies of actin dynamics in living systems. The present invention also relates to methods for preparing such compounds. The synthesis routes combine solid-phase and solution phase peptide synthesis, and has great advantage for efficient preparation of a diverse library of the phalloidin derivatives, especially for the synthesis of phalloidin.
A series of thio- and selenopyrans having two fused indole units, structurally related to indolocarbazoles, have been prepared and evaluated for aryl hydrocarbon receptor (AhR) affinity, leading to the identification of several new significant AhR ligands. In particular, the parent thiopyrano[2,3-b: 6,5-b'] diindole and its derivative having a methyl group in the central ring, as well as the two corresponding selenopyrans, displayed the highest potencies of the compounds tested. (C) 2009 Elsevier Ltd. All rights reserved.