Reaktion #741924

Reaktionsgleichung

hypophosphorous acid

Water

sodium nitrite

water

ethyl 2-amino-5-propyl-trans-4,4a,5,6,8a,9-hexahydrothiazolo-[4,5-g]quinoline-7-carboxylate

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title product

Ausbeute 100.1%

Ethyl 5-propyl-trans-4,4a,5,6,8a,9-hexahydrothiazolo-[4,5-g]quinoline-7-carboxylate

Ausbeute 100.1%

Lösungsmittel

phosphoric acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThis took about 1 hour
2. 2
   workup.ADDITIONThe mixture was poured onto ice
3. 3
   workup.DISSOLUTIONto dissolve the preoipitate
4. 4
   Sonstigethat formed
5. 5
   Extraktionthen the product was extracted into a solution of CHCl3 /i-PrOH (3:1)
6. 6
   SonstigeThis solution was dried
7. 7
   Sonstigeevaporated

Vorschrift

A solution of 0.5 g (1.5 mmole) of ethyl 2-amino-5-propyl-trans-4,4a,5,6,8a,9-hexahydrothiazolo-[4,5-g]quinoline-7-carboxylate (Example 3) in 50 ml of 85% phosphoric acid was cooled to 0° C. Then 110 mg (1.8 mmole) of sodium nitrite dissolved in as small an amount of water as possible was slowly adeed under the surface of the reaction mixture. The resulting mixture was added dropwise to 50 ml of 50% hypophosphorous acid (H3PO2) at 0° C. The mixture was stirred at room temperature until gas evolution ceased. This took about 1 hour. The mixture was poured onto ice, and the hydrogen ion concentration of the mixture was adjusted to pH 11. Water was added to dissolve the preoipitate that formed; then the product was extracted into a solution of CHCl3 /i-PrOH (3:1). This solution was dried using sodium sulfate and evaporated to give 0.46 g of the title product.

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