Potassium Carbonate → 4-Iodo-1-(5,8-dioxaspiro[3.4]octan-2-yl)-1H-pyrazole

HRID 511277Notes

Reaction equation

Br[CH:2]1[CH2:5][C:4]2([O:9][CH2:8][CH2:7][O:6]2)[CH2:3]1.[I:10][C:11]1[CH:12]=[N:13][NH:14][CH:15]=1.C([O-])([O-])=O.[K+].[K+].C1OCCOCCOCCOCCOCCOC1>CN(C=O)C.C(OCC)(=O)C>[CH2:3]1[C:4]2([O:9][CH2:8][CH2:7][O:6]2)[CH2:5][CH:2]1[N:13]1[CH:12]=[C:11]([I:10])[CH:15]=[N:14]1

Participants

Conditions

Temperature: 87.5 °C

Procedure

To a solution of 2-bromo-5,8-dioxa-spiro[3.4]octane (Compound 100F, 19 g, 100 mmol) and 4-iodopyrazole (38.6 g, 200 mmol) in DMF (100 mL) was added powdered K2CO3 (41.4 g, 300 mmol) and 18-crown-6 ether (5.3 g, 20 mmol). The reaction mixture was stirred at 85-90° C. for 2 days. The reaction mixture was diluted with ethyl acetate (400 mL) and washed with water (4×100 mL). The combined organic layers were washed with brine and concentrated, the residue was purified by column chromatography (ethyl acetate/DCM: 5:95) to give 8.8 g (29%) of 1-(5,8-dioxa-spiro[3.4]oct-2-yl)-4-iodo-1H-pyrazole. 1H NMR (CDCl3, 300 MHz): δ=2.87-2.89 (m, 4 H), 3.92-3.96 (m, 4 H), 4.64-4.68 (m, 1 H), 7.53 (s, 2 H).

Workup

washwashed with water (4×100 mL)
washThe combined organic layers were washed with brine
concentrationconcentrated
customthe residue was purified by column chromatography (ethyl acetate/DCM: 5:95)

Sources & evidence

ORD record: ord-f31f90569d7e43d1bd5ea7344c5465b5
Source dataset: uspto-grants-2015_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09096624B2

Reaction notes

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