2-Aminopyridine → 4-Tert-butyl-phenyl-imidazo[1,2-a]pyridine

HRID 729498Notes

Reaction equation

[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][N:3]=1.[C:8]([C:12]1[CH:21]=[CH:20][C:15]([C:16](=O)[CH2:17]Cl)=[CH:14][CH:13]=1)([CH3:11])([CH3:10])[CH3:9].C(=O)(O)[O-].[Na+]>C(O)(C)C>[C:8]([C:12]1[CH:13]=[CH:14][C:15]([C:16]2[N:1]=[C:2]3[CH:7]=[CH:6][CH:5]=[CH:4][N:3]3[CH:17]=2)=[CH:20][CH:21]=1)([CH3:11])([CH3:10])[CH3:9]

Participants

Conditions

Temperature: 80 °C

Procedure

A solution of 2-aminopyridine (0.512 g, 5.44 mmol) and 4-tert-butylphenacyl chloride (1.26 g, 5.98 mmol) in isopropanol (16 mL) was treated with sodium bicarbonate (0.914 g, 10.9 mmol) and heated in a sealed tube at 80° C. overnight. The mixture was concentrated under reduced pressure, re-dissolved in ethyl acetate (200 mL) and washed with water (2×100 mL) and saturated sodium chloride (100 mL). The organic layer was dried over magnesium sulfate, filtered and concentrated under reduced pressure. The crude material was purified by flash silica gel chromatography, eluting with 20% acetone/hexanes to yield 0.841 g (62%) of the purified product. MS (ESI) m/z 251.1528; HPLC (Method B): r.t.=8.4 min., purity 100% at 210-370 nm, 100% at 306 nm. HRMS: calcd for C17H18N2+H+, 251.15427; found (ESI, [M+H]+), 251.1528.

Workup

concentrationThe mixture was concentrated under reduced pressure
dissolutionre-dissolved in ethyl acetate (200 mL)
washwashed with water (2×100 mL) and saturated sodium chloride (100 mL)
dry with materialThe organic layer was dried over magnesium sulfate
filtrationfiltered
concentrationconcentrated under reduced pressure
customThe crude material was purified by flash silica gel chromatography
washeluting with 20% acetone/hexanes

Sources & evidence

ORD record: ord-c5c9674e5236441fa93512615a72e299
Source dataset: uspto-grants-2009_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07582636B2

Reaction notes

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