Science of Synthesis

Rück-Braun, K.; Priewisch, B., Science of Synthesis, (2007) 31, 1404.

Reduction of nitroarenes ‌13‌ with metallic bismuth, or low-valent bismuth species, gives the corresponding diazene oxides ‌14‌ in good to excellent yields (‌Scheme 5‌). A range of functional groups sensitive to reduction, e.g. carbonyl or aliphatic nitro groups and C=C bonds, are tolerated under these conditions.[‌18‌–‌20‌] Activated bismuth may be obtained by reduction of bismuth(III) chloride by sodium borohydride or zinc, or by mechanically crushing bismuth shot in a ball mill under solvent-free conditions.[‌20‌–‌22‌] When sodium borohydride is used as a co-reductant, only substoichiometric amounts of bismuth are necessary. Bismuth and sodium borohydride may be replaced, by antimony and potassium borohydride, respectively, but yields are lower.[‌23‌,‌24‌]

‌Meeeee 8‌ Meeeeeeee Meeeeeeee ee Meeeeeeeeee ee Meeeeee Meeeeeee[‌88‌–‌88‌]

‌Meeeeeeeeee 8‌

Meeeeeeeeeee Meeeeeeee

Mee[8-(8-eeeeee-8-eeeeeeeeeee)eeeeee]eeeeeee Meeee [‌88‌, Me8 = 8-(M8MMMe8MM8)M8M8]; Meeeeee Meeeeeeee:[‌88‌]

M eeeeeee eeee ee ‌88‌ [Me8 = 8-(M8MMMe8MM8)M8M8; 8.88 e, 8 eeee] ee MeMM (88 eM) eee eeeeee ee 8°M eeeee eeeee. Me eeeeee (888 ee, 8.88 eeee) eee eeeee, eeeeeeee ee MeMM8 (888 ee, 88.8 eeee). Meeee eeeeeeee eee 8.8 e ee ee, eee eeeeeee eee eeeeeeee, e eeeee eeeeee ee MeMM eee eeeee ee eee eeeeeeee, eee eeeeeeee eee eeeeeeeee eee 8 e ee ee ee eee. Mee-eeee 8 M MMe (888 eM) eee eeeee, eee eee eeeeeee eee eeeeeee eee 8.8 e. Meeee ‌88‌ [Me8 = 8-(M8MMMe8MM8)M8M8] eeeeeeeee ee e eeeeee eeeee, eeeee eee eeeeeeeee ee eeeeeeeeee, eeeeee eeee M8M, eeeee ee eeeee, eee eeeeeeeeeeeeee (MeMM); eeeee: 888 ee (88%).

References