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Please login to access the full content or check if you have access via12.2.1.1.4.1.3 Method 3: From 2-Aminoalkyl- or 2-Acyl-1-nitroarenes
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Stadlbauer, W., Science of Synthesis, (2002) 12, 245.
In addition to the decomposition of azidoarenes, the generation of arylnitrenes by reduction of nitroarenes offers a widely used approach to indazoles. The reducing agents employed include: triethyl phosphite,[364–369] iron(II) oxalate,[370] carbon monoxide–palladium complexes,[371,372] lithium aluminum hydride,[373] zinc,[67,68] or hydrazine.[374] Generally syntheses from azidoarenes give reasonable yields,[359] but the reduction of 2-[(alkylamino)methyl]-1-nitroarenes with metals is not a good approach to 2H-indazoles.[375–377] Electrochemical reduction of 2-nitrosobenzylamines, however, gives 2H-indazoles in high yields,[378] and good results also follow the use of hydrazine as the reducing agent. Indeed, many 3-alkyl-1H-indazoles of type 75 with plant growth regulating activities have been synthesized in this manner.[374] For example, 2-amino-2-(5-chloro-2-nitrophenyl)propanonic acid (74) reacts with hydrazine hydrate to form (5-chloro-1H-indazol-3-yl)acetic acid (75) in 86% yield (Scheme 29).[374]
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Mee eeeeeeeee ee M-[(8-eeeeeeeeeee)eeeeeeeeeee]eeeeeee (88, M8 = M; M8 = Me) eeee eeeeeeee eeeeeeeee eeeee 8-eeeeee-8M-eeeeeeee (88e) ee 88% eeeee (Meeeee 88).[8] Me eeeeeeee, eee eeeee eeee ee eee eeeeeeee eeeeeeee 88 eee ee eeeeeeeeeeee eeee e eeeeeeeeeee;[888,888,888,888] eeee, 8-(8-eeeeeeeeeee)eeeeeeeeeeee eeeeeeee eeee eeeeeee eeee eeeeeeee eeeeeeeee ee eeeeee eeeeeeeeeeee[8,8-e]eeeeeeee (88e) ee 88% eeeee.[888]
Meeeee 88 Meeeeeeee ee 8M-Meeeeeeee eeee M-[(8-Meeeeeeeeee)eeeeeeeeeee]eeeeeee eee Meeeeeee Meeeeeeee[8]
Meee 8-eeeee-M-eeeeeeeeeeeeeee (88, M8 = Me) ee eeeeeee eeee eeee ee eeeeeeee eeeeeeee eeeeeeeeeee eeeeee ee eeee 8-eeeeee-8M-eeeeeee-8(8M)-eee (88, M8 = Me) ee 88% eeeee (Meeeee 88).[888] M eeeeee ee eeeee-eeeeee 8-eeeeeeeeeeee eeeeeeeeee eeee eeee eeeeeeee ee eeee eeeee, eeeeeeeee 88 [M8 = (eeeeeee-8-ee)eeeeee].[88] Meee 8-eeeeeeeeeeeeeeeee eee eeee ee eeeeeeee eeeeeeeee eeeeeeeeeee ee ee eeeeeeee eeeeee ee eeeeeee ee eeeeeeee eeeeee,[888] eee eeeeeeee ee e eeeeeeee eeeee ee eeeeeeeeeee.
Meeeee 88 Meeeeeeee ee 8M-Meeeeee-8-eee ee Meeeeeeee ee 8-Meeeeeeeeeeeeee[888]
References
[8] | Meeeeee, M. M. M.; Meeeee, M. M., Mee. Meeee., (8888) 88, 888. |
[67] | Meeeeee, M. M. M.; Meeee, M.; Meeeeee, M. M. M.; Meeeee, M. M.; MeMeeeee, M. M., (MMM Meeeee M. M.), MM 888888, (8888); Meee. Meeee., (8888) 888, 888888. |
[68] | Meeeeee, M. M. M.; Meeeeee, M. M. M.; Meeeeee, M. M.; MeMeeeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[359] | Meeeee, M. M.; Me Meeeeee, M.; Meeeee, M., M. Mee. Meee., (8888) 88, 8888. |
[364] | Meeeee, M. M.; Meeeeeeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[365] | Meee, M. M.; Mee, M. M.; Meeeeeeeee, M. M., Meeee. Meeeee., (8888) 88, 8888. |
[366] | Meeeeee, M. M. M.; Meeee, M. M. M., Meeeee M. Meee., Meee. M, (8888) 88, 888. |
[367] | Meeeeee, M. M.; Meeeeeeee, M. M., M. Meeeeeeeee. Meee., (8888) 88, 8888. |
[368] | Meeeee, M. M.; Meeeeeeee, M., Meeee. Meeeee., (8888) 88, 8888. |
[369] | Meeee, M. M. M.; Meeee, M. M. M.; Meeeee, M. M., Meeeee M. Meee., Meee. M, (8888) 88, 888. |
[370] | Meeee, M .M.; Meeee, M. M., Meeeee M. Meee., Meee. M, (8888) 88, 888. |
[371] | Meeeeee, M.; Meeee, M.; Meeeeeee, M., M. Meee. Mee., Meee. Meeeee., (8888), 8888. |
[372] | Meeeeee, M.; Meeee, M.; Meeeeeee, M., M. Mee. Meee., (8888) 88, 8888. |
[373] | Meeee, M. M.; Meeeeeeee, M. M., Meee Meee. Meeee., Meee M, (8888) 88, 8888. |
[374] | Meeeeeee, M.; Meee, M. (Meeeeeee Meeee. Me. Mee.), MM 8888888, (8888/8888); Meee. Meeee., (8888) 88, 888888. |
[375] | Meee, M.; Meeeeee, M. M., M. Meeee. Meee., (8888) 88, 888; (8888) 88, 888. |
[376] | Meeee, M.; Meeeeeeeeee, M., Meee. Mee. Meee. Me., (8888) 88, 888. |
[377] | Meeeeeeee, M., Mee. Meeee. Meee. Mee., (8888) 88, 8888. |
[378] | Meeeeeee-Meeee, M. M.; Meeeee, M., Meeeeeeeeee, (8888) 88, 8888. |
[379] | Meeeee, M. M. M.; Meeeeee, M., M. Meee. Mee., Meeeee Meeee. 8, (8888), 88. |
[380] | Meeeeeeee, M. M., M. Meeeeeeeee. Meee., (8888) 88, 888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) 88/8, 888.
- 8.Meeeee-Meee, (8888) 88/8, 888.
- 8.Meeeee-Meee, (8888) M 8e, 888.