Reaktion #2061641

Reaktionsgleichung

acetic anhydride

dimethyl 5-formylpyridine-2,3-dicarboxylate

N-methylethylene diamine

para-toluenesulfonic acid

→

title compound

Ausbeute 57.1%

Dimethyl 5-(1-acetyl-3-methyl-2-imidazolidinyl)pyridine-2,3-dicarboxylate

Ausbeute 57.1%

Lösungsmittel

pyridine

methylene chloride

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux temperature for 3 hours
2. 2
   SonstigeDuring this process, water is removed by placement of an addition funnel
3. 3
   workup.ADDITIONcontaining 3 angstrom molecular sieves between the reaction flask
4. 4
   EinengenThe reaction mixture is concentrated in vacuo
5. 5
   workup.DISSOLUTIONdissolved in methylene chloride (30 mL)
6. 6
   Waschenis washed with saturated aqueous sodium bicarbonate solution
7. 7
   TrocknenThe organic solution is dried over anhydrous magnesium sulfate
8. 8
   Einengenconcentrated in vacuo
9. 9
   Sonstigeto give a residue
10. 10
    SonstigeThe pyridine is removed in vacuo
11. 11
    Sonstigeto yield an oil
12. 12
    Waschenwashed with saturated aqueous sodium bicarbonate
13. 13
    TrocknenThe organic solution is dried over anhydrous magnesium sulfate
14. 14
    Einengenconcentrated in vacuo
15. 15
    Sonstigepurified by chromatography

Vorschrift

A solution of dimethyl 5-formylpyridine-2,3-dicarboxylate (0.75 g, 0.0036 mol), N-methylethylene diamine (0.38 mL, 0.0044 mol) and a catalytic amount of para-toluenesulfonic acid in toluene (10 mL) is heated at reflux temperature for 3 hours. During this process, water is removed by placement of an addition funnel containing 3 angstrom molecular sieves between the reaction flask and the reflux condensor. The reaction mixture is concentrated in vacuo, dissolved in methylene chloride (30 mL) and is washed with saturated aqueous sodium bicarbonate solution. The organic solution is dried over anhydrous magnesium sulfate and concentrated in vacuo to give a residue. The residue is dissolved in pyridine (10 mL) at 0° C. and treated with acetic anhydride (0.34 mL, 0.0036 mol). The reaction mixture is stirred for 1 hour at 0° C. and for 66 hours at room temperature. The pyridine is removed in vacuo to yield an oil. The oil is dissolved in methylene chloride and washed with saturated aqueous sodium bicarbonate. The organic solution is dried over anhydrous magnesium sulfate, concentrated in vacuo and purified by chromatography using silica gel and 10% triethylamine in ethyl acetate as eluant to yield the title compound (0.66 g, 56%) as a yellow oil, identified by IR and NMR spectral analyses.

Quelle