5- nitrothiophene-2-carboxaldehyd

The testing of 2-nitrobenzyltriphenylphosphonium bromide and methyl 4-formylbenzoate and four other aldehydes, 3-benzyloxybenzaldehyde, 2-naphthaldehyde, 5-nitrothiophene-2-carboxaldehyde and 4-[3-dimethylamino)propoxy]benzaldehyde, has been reported [13]. 

FIGLfRE 15. ESR spectrum of the radical anion generated from the reaction of 5-nitrothiophene-2-carboxaldehyde with germylhthiums.l2-crown-4. From Reference 197 with permission from Gordon and Breach Publishing, copyright Taylor Francis... 

The authors then prepared a small library of compounds by sequentially substituting different aldehydes in the reaction. Reaction of 2-nitrobenzyl(tri-phenylphosphonium) bromide 21 with 3-benzyloxybenzaldehyde 23, 2-naphth-aldehyde 24 and 5-nitrothiophene-2-carboxaldehyde 25 produced stilbenes 26-28 in 55%, 47% and 54% overall conversion, respectively (Fig. 14.7). These results show that for a series of aromatic aldehydes of comparable reactivity, the products are obtained in similar conversions, which demonstrates the versatility of the methodology for the preparation of larger libraries of compounds. 

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