e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521

New practical synthesis of indazoles via condensation of o-fluorobenzaldehydes and their o-methyloximes with hydrazine

…, MC Hsu, D Fernando, MR Leanna

Index: Lukin, Kirill; Hsu, Margaret C.; Fernando, Dilinie; Leanna, M. Robert Journal of Organic Chemistry, 2006 , vol. 71, # 21 p. 8166 - 8172

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Citation Number: 74

Abstract

The reaction of o-fluorobenzaldehydes and their O-methyloximes with hydrazine has been developed as a new practical synthesis of indazoles. Utilization of the methyloxime derivatives of benzaldehydes (in the form of the major E-isomers) in this condensation effectively eliminated a competitive Wolf-Kishner reduction to fluorotoluenes, which was observed in the direct preparations of indazoles from aldehydes. Reaction of Z-isomers of ...

Benzyl bromide Structure

4-Bromoindazole Structure

4-Bromoindazole

~0%

2-benzyl-4-bromo-2H-indazole Structure

2-benzyl-4-brom...

1-benzyl-4-bromoindazole Structure

1-benzyl-4-brom...

2-Bromo-6-fluorobenzaldehyde Structure

2-Bromo-6-fluor...

~%

2-benzyl-4-bromo-2H-indazole Structure

2-benzyl-4-brom...

2-bromo-6-fluorobenzaldehyde hydrazone Structure

2-bromo-6-fluor...

~%

2-benzyl-4-bromo-2H-indazole Structure

2-benzyl-4-brom...

N/A Structure

~%

2-benzyl-4-bromo-2H-indazole Structure

2-benzyl-4-brom...

2-Bromo-6-fluorobenzaldehyde Structure

2-Bromo-6-fluor...

~0%

2-Bromo-6-fluorotoluene Structure

2-Bromo-6-fluor...

4-Bromoindazole Structure

4-Bromoindazole

2-bromo-6-fluorobenzaldehyde hydrazone Structure

2-bromo-6-fluor...

~99%

2-Bromo-6-fluorotoluene Structure

2-Bromo-6-fluor...

4-Bromo-2-fluorobenzaldehyde Structure

4-Bromo-2-fluor...

~80%

6-Bromoindazole Structure

6-Bromoindazole

2-Fluorobenzaldehyde Structure

2-Fluorobenzaldehyde

~28%

1H-Indazole Structure

2-Fluorotoluene Structure

2-Fluorotoluene

2-Fluoro-6-methoxybenzaldehyde Structure

2-Fluoro-6-meth...

~46%

4-Methoxy-1H-indazole Structure

4-Methoxy-1H-in...

3-Chloro-2-fluorobenzaldehyde Structure

3-Chloro-2-fluo...

~74%

7-chloro-1H-indazole Structure

7-chloro-1H-indazole

Benzyl bromide Structure

4-Bromoindazole Structure

4-Bromoindazole

~39%

2-benzyl-4-bromo-2H-indazole Structure

2-benzyl-4-brom...

1-benzyl-4-bromoindazole Structure

1-benzyl-4-brom...

2-Bromo-6-fluorobenzaldehyde Structure

2-Bromo-6-fluor...

~%

1-benzyl-4-bromoindazole Structure

1-benzyl-4-brom...

2-bromo-6-fluorobenzaldehyde hydrazone Structure

2-bromo-6-fluor...

~%

1-benzyl-4-bromoindazole Structure

1-benzyl-4-brom...

N/A Structure

~%

1-benzyl-4-bromoindazole Structure

1-benzyl-4-brom...

Benzylhydrazine Structure

Benzylhydrazine

~%

1-benzyl-4-bromoindazole Structure

1-benzyl-4-brom...

N/A Structure

~%

1-benzyl-4-bromoindazole Structure

1-benzyl-4-brom...

4-Bromoindazole Structure

4-Bromoindazole

2-Chloro-6-fluorobenzaldehyde Structure

2-Chloro-6-fluo...

~13%

2-Chloro-6-fluorotoluene Structure

2-Chloro-6-fluo...

4-Chloro-1H-indazole Structure

4-Chloro-1H-indazole