N-Formylmorpholine → 4,4-dimethyl-3,4-dihydro-2H-thiochromene-6-carbaldehyde

HRID 1386479Notes

Reaction equation

Br[C:2]1[CH:3]=[CH:4][C:5]2[S:10][CH2:9][CH2:8][C:7]([CH3:12])([CH3:11])[C:6]=2[CH:13]=1.[Mg].[CH:15](N1CCOCC1)=[O:16].[NH4+].[Cl-]>C1COCC1>[CH:15]([C:2]1[CH:3]=[CH:4][C:5]2[S:10][CH2:9][CH2:8][C:7]([CH3:12])([CH3:11])[C:6]=2[CH:13]=1)=[O:16]

Participants

Conditions

Temperature: -10 °C

Procedure

The 6-bromo-4,4-dimethyl-3,4-dihydro-2H-1-benzothiopyran (2.62 g, 10 mmol) prepared in the previous step (b) and in solution in 5 ml of anhydrous THF, is added at 66° C. to magnesium (0.30 g, 12 mmol) in 1 ml of anhydrous THF. The mixture is agitated at reflux of the THF until quasi-complete consumption of the magnesium (30 minutes). The reaction medium is then cooled to −10° C. and at this temperature, the N-formylmorpholine (1.2 ml, 12 mmol) in 2 ml of THF is added. At the end of the addition, the reaction medium is brought to ambient temperature for 1 hour. After hydrolysis by 10 ml of an aqueous saturated NH4Cl solution at 0° C. and extraction with ethyl ether (5×30 ml), the organic phase is dried over MgSO4, filtered and evaporated. The raw product is purified by flash chromatography on silica (eluent petroleum ether:ethyl ether:100:5). 2.00 g of 6-formyl-4,4-dimethyl-3,4-dihydro-2H-1-benzothiopyran is obtained (yield=61%).

Workup

additionAt the end of the addition
extractionextraction with ethyl ether (5×30 ml)
dry with materialthe organic phase is dried over MgSO4
filtrationfiltered
customevaporated
customThe raw product is purified by flash chromatography on silica (eluent petroleum ether:ethyl ether:100:5)

Sources & evidence

ORD record: ord-b7013b222e264f7a84207b40c0a72262
Source dataset: uspto-grants-2001_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06265423B1

Reaction notes

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