ChemicalBook CAS DataBase List 8H-Imidazo[2,1-c][1,4]oxazine-2-carboxaldehyde, 5,6-dihydro- (9CI)

8H-Imidazo[2,1-c][1,4]oxazine-2-carboxaldehyde, 5,6-dihydro- (9CI) synthesis

6synthesis methods

Product Name:8H-Imidazo[2,1-c][1,4]oxazine-2-carboxaldehyde, 5,6-dihydro- (9CI)
CAS Number:623564-42-1
Molecular formula:C7H8N2O2
Molecular Weight:152.15

8H-Imidazo[2,1-c][1,4]oxazine-2-carboxylic acid, 5,6-dihydro-, ethyl ester

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8H-Imidazo[2,1-c][1,4]oxazine-2-carboxaldehyde, 5,6-dihydro- (9CI)

623564-42-1
39 suppliers
$130.00/50mg

Yield:623564-42-1 41%

Reaction Conditions:

Stage #1: C₉H₁₂N₂O₃with diisobutylaluminium hydride in tetrahydrofuran at -78 - 40; for 3 h;
Stage #2: with water;ammonium chloride in tetrahydrofuran;Product distribution / selectivity;

Steps:

9

Example 9Alternative Preparation of 5,6-Dihydro-8H-imidazo[2,1-c][1,4]oxazine-2-carbaldehyde (1); To a stirred solution of morpholin-3-ylideneamine hydrochloride salt (1.3 g, 10 millimolar (mmol)) in DME (50 mL) at room temperature was added an excess of anhydrous K₂CO₃and the mixture stirred for 10 minutes. Then ethyl-bromopyruvate (10) (2.94 g, 15 mmol) was added and the mixture stirred at room temperature for 4 hours, then refluxed for 16 hours. Examination of TLC by UV visualization using 1:1:0.05 ethylacetate:hexane:methanol showed only one product. The reaction mixture was concentrated and extracted with chloroform. The chloroform extract was dried over anhydrous Na₂SO₄, filtered, and concentrated. The crude product was purified by SiO₂column chromatography using 1:1:0.05 ethylacetate:hexane:methanol as eluent, yielding 980 mg of a pale yellow liquid (50% yield).The intermediate ester (11) (600 mg, 3.06 mmol) was dissolved in anhydrous THF (50 mL) and cooled to -78° C. To the stirred reaction mixture, DIBAL (1 molar (M) solution, 3.5 mL) was slowly added. The reaction mixture was stirred for 2 hours while the temperature was slowly elevated to -40° C. and then stirred for 1 hour at 40° C. The reaction mixture was then quenched with a saturated NH₄Cl solution and extracted with chloroform. The chloroform extract was washed once with a saturated brine solution. The organic layer was dried over anhydrous Na₂SO₄and filtered. It was concentrated and purified by SiO₂column chromatography, eluting with ethylaceate:hexane (4:1), yielding 250 mg (41%) of the product Compound 1 having the same ¹H-NMR spectrum as above.