Reaktion #989730

Reaktionsgleichung

2-methyl-7-(2,4,6-trimethyl-phenyl)-2H-indazole

lithium diisopropylamide

tetrahydrofuran heptane ethylbenzene

Acetaldehyde

→

1-[2-methyl-7-(2,4,6-trimethyl-phenyl)-2H-indazol-3-yl]-ethanol

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigerechilled to −78° C. for 15 m
2. 2
   workup.STIRRINGthe resulting yellow solution was stirred for 90 m
3. 3
   Sonstigethen quenched with silica gel
4. 4
   Einengenconcentrated

Vorschrift

To a solution of the above-prepared impure 2-methyl-7-(2,4,6-trimethyl-phenyl)-2H-indazole (0.500 g) in 10 mL of THF at −78° C. was added a 2.0 M solution of lithium diisopropylamide in tetrahydrofuran/heptane/ethylbenzene (1.2 mL, 2.4 mmol). The yellow solution was stirred at 0-5° C. for 15 m, and the resulting purple solution rechilled to −78° C. for 15 m. Acetaldehyde (0.14 mL, 2.5 mmol) was added, and the resulting yellow solution was stirred for 90 m then quenched with silica gel and concentrated. Column chromatography (0→50% EtOAc/hexanes) afforded of 1-[2-methyl-7-(2,4,6-trimethyl-phenyl)-2H-indazol-3-yl]-ethanol (12a: R=Me, R′=2,4,6-trimethylphenyl, E=CH(OH)Me; 0.280 g; 48%; m.p. 246) as a white solid.

Quelle