Hydrochloric Acid → 4,5-Dihydro-imidazo-[1,2-a]-quinoxaline-2-methanol

HRID 1632191Notes

Reaction equation

HRID 1632191 reaction equation
[BH4-].[Li+].[CH:3]1[N:7]2[C:8]3[C:13]([N:14]=[CH:15][C:6]2=[N:5][C:4]=1[C:16](OCC)=[O:17])=[CH:12][CH:11]=[CH:10][CH:9]=3.Cl.C(=O)([O-])[O-].[Na+].[Na+]>O1CCCC1>[CH:3]1[N:7]2[C:8]3[C:13]([NH:14][CH2:15][C:6]2=[N:5][C:4]=1[CH2:16][OH:17])=[CH:12][CH:11]=[CH:10][CH:9]=3

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 10340Sodium CarbonateHCID 4148881Lithium borohydrideHCID 13228325Ethyl imidazo[1,2-a]quinoxaline-2-carboxylate

Product 1

HCID 137704784,5-Dihydro-imidazo-[1,2-a]-quinoxaline-2-methanolYield 70.7%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

2.8 g of lithium borohydride were added to a solution of 10 g of ethyl imidazo-[1,2-a]-quinoxaline-2-carboxylate of Step B in 230 ml of anhydrous tetrahydrofuran and the mixture was stirred at reflux for 18 hours. The resulting yellow suspension was poured into dilute hydrochloric acid to react with the boron complex and the mixture was made alkaline with sodium carbonate addition. The mixture was extracted with ethyl acetate and the organic phase was evaporated to dryness to obtain 5.9 g of 4,5-dihydro-imidazo-[1,2-a]-quinoxaline-2-methanol in the form of a buff crystalline solid melting at 172°-174° C. after crystallization from ethyl acetate to obtain a white crystalline solid.

Workup

  1. temperatureat reflux for 18 hours
  2. customto react with the boron complex
  3. extractionThe mixture was extracted with ethyl acetate
  4. customthe organic phase was evaporated to dryness

Sources & evidence

ORD record
ord-627a8594a408494ea17a6c7124006b45
Source dataset
uspto-grants-1984_10
Patent number
US04474784

Reaction notes

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