Reaktion #2507839

Reaktionsgleichung

chloroenal

NaOH

Phosphorus oxychloride

chloroenal

sodium hydrogen carbonate

1-(3-propoxy-5,6,7,8-tetrahydro-5,5,8,8,-tetramethylnaphthalen-2-yl)ethanone

→

6-ethynyl-1,1,4,4,-tetramethyl-7-propoxy-1,2,3,4-tetrahydronaphthalene

Ausbeute 39.0%

Lösungsmittel

dioxane water

dioxane H2O

dimethyl formamide

brine

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGwas stirred for 12 hours
2. 2
   ExtraktionEthyl acetate extraction
3. 3
   Sonstigeafforded the crude product
4. 4
   workup.STIRRINGthe reaction mixture was stirred for 2 hours
5. 5
   Sonstigeto yield an orange reaction solution
6. 6
   TemperaturThe reaction solution was cooled to room temperature
7. 7
   Extraktionextracted with EtOAc
8. 8
   TrocknenThe organic phase was dried (MgSO4)
9. 9
   Filtrationfiltered
10. 10
    Einengenconcentrated
11. 11
    Sonstigeto afford an orange oil which
12. 12
    Sonstigewas purified by radial chromatography (10:1 hexane:ethyl acetate)

Vorschrift

Phosphorus oxychloride (0.234 grams, 0.142 ml, 1.52 mmol) was added dropwise to dimethyl formamide (DMF) (4 ml) at room temperature under a nitrogen atmosphere. The solution was stirred for 30 minutes. The 1-(3-propoxy-5,6,7,8-tetrahydro-5,5,8,8,-tetramethylnaphthalen-2-yl)ethanone was added quickly (in one portion) to the orange solution, the reaction solution was heated to 60° C. and was stirred for 12 hours. The obtained dark brown solution was poured into ice water and the aqueous layer was adjusted to pH 7 with solid sodium hydrogen carbonate. Ethyl acetate extraction afforded the crude product, the chloroenal (6-[1-hydroxy,2-chloro-ethenyl]-1,1,4,4-tetramethyl-7-propoxy-1,2,3,4-tetrahydronaphthalene), 0.128 grams, as an orange/brown oil. A solution of the crude chloroenal in dioxane:water (3:2; 5 ml) was added to a solution of NaOH (0.061 grams, 1.52 mmol) in dioxane: H2O (3:2; 20 ml), at 80° C., and the reaction mixture was stirred for 2 hours, to yield an orange reaction solution. The reaction solution was cooled to room temperature, poured into brine and extracted with EtOAc. The organic phase was dried (MgSO4), filtered, and concentrated to afford an orange oil which was purified by radial chromatography (10:1 hexane:ethyl acetate) to give the product 6-ethynyl-1,1,4,4,-tetramethyl-7-propoxy-1,2,3,4-tetrahydronaphthalene (39%) as a yellow oil [1H-NMR (400 MHz, CDCl3): d 7.38(s, 1H, Ar—H), 6.76(s,1H, Ar—H), 3.98 (t, J=6.6 Hz, 2H, OCH3), 3.19 (s, 1H, CH),1.83 (m, 2H, CH2),1.66 (m, 2H, 2CH2),1.26 (s, 6H, 2CH3),1.23 (s, 6H, 2CH3), 0.93 (t, J=7.4 Hz, 3H, CH3)].

Quelle