Methyl iodide → 3-iodo-1,5,5-trimethyl-4,5,6,7-tetrahydro-1H-indazole

HRID 245815Notes

Reaction equation

[I:1][C:2]1[C:10]2[CH2:9][C:8]([CH3:12])([CH3:11])[CH2:7][CH2:6][C:5]=2[NH:4][N:3]=1.[CH3:13]C(C)([O-])C.[K+].CI>C1COCC1>[I:1][C:2]1[C:10]2[CH2:9][C:8]([CH3:12])([CH3:11])[CH2:7][CH2:6][C:5]=2[N:4]([CH3:13])[N:3]=1

Participants

Conditions

Temperature: 0 °C

Procedure

In a round-bottomed flask, 3-iodo-5,5-dimethyl-4,5,6,7-tetrahydro-1H-indazole (642 mg, 2.33 mmol) was dissolved in THF (8.5 ml). The solution was cooled to 0° C. and potassium tert-butoxide (365 mg, 3.26 mmol) was added. The reaction mixture was stirred at 0° C. for 40 min then methyl iodide (0.18 ml, 2.88 mmol) was added dropwise. The reaction mixture was warmed to room temperature and stirred for 1.5 h then quenched with water and extracted with EtOAc (2×). The combined organic layers were washed with water and brine then dried over sodium sulfate, filtered and concentrated. The residue was chromatographed over silica gel with EtOAc/Hexanes (gradient 0-15% EtOAc) to provide 497 mg (74%) of 3-iodo-1,5,5-trimethyl-4,5,6,7-tetrahydro-1H-indazole as a white solid. 1H NMR (CDCl3, 300 MHz): δ (ppm) 3.76 (s, 3H), 2.53 (t, J=6.4 Hz, 2H), 2.11 (s, 2H), 1.58 (t, J=6.6 Hz, 2H), 0.99 (s, 6H).

Workup

temperatureThe reaction mixture was warmed to room temperature
stirringstirred for 1.5 h
customthen quenched with water
extractionextracted with EtOAc (2×)
washThe combined organic layers were washed with water and brine
dry with materialthen dried over sodium sulfate
filtrationfiltered
concentrationconcentrated
customThe residue was chromatographed over silica gel with EtOAc/Hexanes (gradient 0-15% EtOAc)

Sources & evidence

ORD record: ord-3f2cbe88a32f4fcfada3140a01565d1a
Source dataset: uspto-grants-2014_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08658646B2

Reaction notes

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