Hydrochloric Acid → Ethyl 5,6,7,8-tetrahydroimidazo[1,2-a]pyridine-6-carboxylate hydrochloride

HRID 1055156Notes

Reaction equation

[ClH:1].[N:2]1[CH:3]=[CH:4][N:5]2[CH:10]=[C:9]([C:11]([O:13][CH3:14])=[O:12])[CH:8]=[CH:7][C:6]=12.[CH2:15](O)C>[Pd]>[ClH:1].[N:2]1[CH:3]=[CH:4][N:5]2[CH2:10][CH:9]([C:11]([O:13][CH2:14][CH3:15])=[O:12])[CH2:8][CH2:7][C:6]=12

Participants

Conditions

Temperature: 60 °C

Procedure

Add 5 N hydrochloric acid (100 mL; 500.00 mmoles) and ethanol (200 mL) to a flask containing methyl imidazo[1,2-a]pyridine-6-carboxylate (4.98 g; 1.0 equiv; 28.27 mmoles) and 10% palladium on carbon (3.01 g; 0.1 equiv; 2.83 mmoles). Evacuate and backfill the reaction vessel with nitrogen (3×), then re-evacuate and backfill the reaction with hydrogen (3×). Heat the reaction mixture to 60° C. and vigorously stir under a hydrogen atmosphere for 24 hours, then evacuate and backfill the reaction vessel with nitrogen (3×) and filter the reaction mixture through Celite™, rinsing the filter cake with ethanol (100 mL). Concentrate the filtrate, add toluene (200 mL), and concentrate to dryness (repeat 2 times) to afford ethyl 5,6,7,8-tetrahydroimidazo[1,2-a]pyridine-6-carboxylate hydrochloride (5.74 g; 88%) as a white solid. MS (m/z): 195(M+1).

Workup

customEvacuate
customre-evacuate
customthe reaction with hydrogen (3×)
customevacuate
filtrationfilter the reaction mixture through Celite™
washrinsing the filter cake with ethanol (100 mL)
concentrationConcentrate the filtrate
additionadd toluene (200 mL)
concentrationconcentrate to dryness (repeat 2 times)

Sources & evidence

ORD record: ord-8b2081836c9a4cf08e2a6fc0b5f7f259
Source dataset: uspto-grants-2016_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09394317B2

Reaction notes

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