Aluminium lithium hydride → N-[2-(Hydroxymethyl)-3,4-dihydro-2H-1-benzopyran-6-yl]acetamide
Reaction equation
[C:1]([NH:4][C:5]1[CH:6]=[C:7]2[C:12](=[CH:13][CH:14]=1)[O:11][CH:10]([C:15](OCC)=[O:16])[CH2:9][CH2:8]2)(=[O:3])[CH3:2].[H-].[Al+3].[Li+].[H-].[H-].[H-]>CCOCC>[C:1]([NH:4][C:5]1[CH:6]=[C:7]2[C:12](=[CH:13][CH:14]=1)[O:11][CH:10]([CH2:15][OH:16])[CH2:9][CH2:8]2)(=[O:3])[CH3:2]Participants
Conditions
- Temperature
- 0 °C
Procedure
To a solution of 3.0 grams of ethyl 6-acetamidochromane-2-carboxylate (Example 12) dissolved in 20 mL of dry ether is added dropwise a solution of 1 mL of lithium aluminum hydride (70% in benzene) dissolved in about 2 mL of dry ether, and the solution is refluxed for about 1 h. An additional 1 mL of lithium aluminum hydride is added to the mixture, and the mixture refluxed for an additional 1-2 h. The reaction mixture is cooled to 0° C. and the excess hydride quenched by adding 10-12 mL of 1 N H2SO4, followed by 100 mL of water. The precipitate is filtered and washed well with ether. The aqueous phase is separated, extracted several times with 60-mL aliquots of ether. The combined extracts are washed with water and dried over anhydrous MgSO4. Evaporation to dryness under vacuum affords about 2.4 g of 6-acetamido-2-hydroxymethylchromane (about 90% yield).
Workup
- temperaturethe solution is refluxed for about 1 h
- temperaturethe mixture refluxed for an additional 1-2 h
- customthe excess hydride quenched
- additionby adding 10-12 mL of 1 N H2SO4
- filtrationThe precipitate is filtered
- washwashed well with ether
- customThe aqueous phase is separated
- extractionextracted several times with 60-mL aliquots of ether
- washThe combined extracts are washed with water
- dry with materialdried over anhydrous MgSO4
- customEvaporation to dryness under vacuum
Sources & evidence
- ORD record
- ord-0a0b2f58565f4d46b767b2dc29db6ebd
- Source dataset
- uspto-grants-2005_06
- Patent number
- US06903227B2
Reaction notes
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