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

HRID 236316Notes

Reaction equation

HRID 236316 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-75add7a1f2b14e809709b36d7fd63bb2
Source dataset
uspto-grants-1987_02
Patent number
US04644002

Reaction notes

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