Sulfuric Acid → 6-Methoxy-1,3-benzothiazole-2-carbaldehyde

Temperatur

-30 °C

2-Cyano-6-methoxybenzothiazole (10.0 g, 52.6 mmol) was suspended in a mixture of anhydrous ether (400 ml) and 2-propanol (36 ml). The suspension was cooled to about -30° C. by a dry-ice bath. Lithium aluminum hydride (7.0 g, 184.5 mmol) was added slowly while keeping the reaction temperature below -30° C. under argon atmosphere. The reaction mixture was stirred for 1 hr after the addition of lithium aluminum hydride and then poured slowly into a mixture of 2 N sulfuric acid (900 ml) and ethyl acetate (500 ml). After stirring for 10 min the organic layer was separated and the aqueous layer was extracted with ethyl acetate (200 ml). The combined organic phase was washed with water (200 ml) and then dried with anhydrous sodium sulfate (50 g) overnight. The dried solution was concentrated and then flash chromatographed on silica gel to give 3.1 g (30.5%) of a yellowish solid.

1. customthe reaction temperature below -30° C.
2. stirringAfter stirring for 10 min the organic layer
3. customwas separated
4. extractionthe aqueous layer was extracted with ethyl acetate (200 ml)
5. washThe combined organic phase was washed with water (200 ml)
6. dry with materialdried with anhydrous sodium sulfate (50 g) overnight
7. concentrationThe dried solution was concentrated
8. customflash chromatographed on silica gel

ORD-Eintrag

ord-b79409986bce4557842dedb76cbd3450

Quelldatensatz

uspto-grants-2000_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06140051