Reaktion #91804

Reaktionsgleichung

acetic anhydride

( iv )

5-Cyclopropyl-2,4-dinitrobenzaldehyde

4-chloroaniline

sodium cyanide

sodium cyanide

→

2-(4-chlorophenyl)-5-cyclopropyl-6-nitro-2H-indazole-3-carbonitrile 1-oxide

Ausbeute 108.4%

Lösungsmittel

MeOH

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeto obtain a complete solution
2. 2
   workup.ADDITIONwas added
3. 3
   Temperaturthe reaction mixture was cooled to RT
4. 4
   Sonstigethe solids separated by filtration
5. 5
   workup.DISSOLUTIONThe solid cake was dissolved in chloroform (400 ml)
6. 6
   Waschenthe organics washed with water (2×100 ml)
7. 7
   Trocknendried (MgSO4)
8. 8
   Einengenconcentrated in vacuo

Vorschrift

To a stirred suspension of (iv) (20 g, 0.09 mol) in acetic acid (400 mL) was added 4-chloroaniline (21.6 g, 0.17 mol) and the reaction heated at 60° C. to obtain a complete solution. To this solution was added sodium cyanide (20 g, 0.41 mol) portionwise over 20 min. The reaction mixture was stirred for 5 min whereupon acetic anhydride (6 mL) was added. Upon the formation of a precipitate, an additional quantity of sodium cyanide (20 g, 0.41 mol) was added portionwise. After stirring for 1 h, the reaction mixture was cooled to RT, diluted with MeOH (30 ml) and the solids separated by filtration. The solid cake was dissolved in chloroform (400 ml) and the organics washed with water (2×100 ml), dried (MgSO4) and concentrated in vacuo to give the intermediate 2-(4-chlorophenyl)-5-cyclopropyl-6-nitro-2H-indazole-3-carbonitrile 1-oxide (34.6 g). ESI-MS m/z calculated for [M+H]+: 355.1. found: 355.2. 1H NMR (400 MHz, CDCl3) δ 8.32 (s, 1H), 7.72-7.50 (m, 5H), 2.44-2.30 (m, 1H), 1.18-1.05 (m, 2H), 0.85-0.71 (m, 2H).

Quelle