Reaction #1973949

Reaction equation

Phosphorus trichloride

diethyl 7-(hydroxymethyl)dipyrido[3,2-f:2′,3′-h]quinoxaline-2,3-dicarboxylate

→

glass

Yield 26.0%

Diethyl 7-(chloromethyl)dipyrido[3,2-f:2′,3′-h]quinoxaline-3,2-dicarboxylate

Yield 26.0%

Solvents

CHCl3

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was heated
2. 2
   Temperatureunder reflux for 6 h
3. 3
   OtherThe reaction was quenched by addition of concentrated Na2CO3 solution (150 ml)
4. 4
   OtherThe layers were separated
5. 5
   Extractionthe water was extracted by CH2Cl2 (3×150 ml) and CHCl3 (1×50 ml)
6. 6
   DryingThe organic layer was dried over K2CO3
7. 7
   OtherThe solvent was removed under reduced pressure
8. 8
   Otherto give the crude product
9. 9
   OtherPurification

Procedure

Phosphorus trichloride (473 mg, 3.44 mmol) was added to a solution diethyl 7-(hydroxymethyl)dipyrido[3,2-f:2′,3′-h]quinoxaline-2,3-dicarboxylate (350 mg, 0.86 mmol) in CHCl3 (150 ml). The reaction mixture was heated under reflux for 6 h and allowed to cool down to room temperature afterwards. The reaction was quenched by addition of concentrated Na2CO3 solution (150 ml). The layers were separated and the water was extracted by CH2Cl2 (3×150 ml) and CHCl3 (1×50 ml). The organic layer was dried over K2CO3. The solvent was removed under reduced pressure to give the crude product. Purification was achieved by chromatography on alumina (gradient elution: CH2Cl2 to 2% CH3OH—CH2Cl2) The product was obtained as a yellow glass (95 mg, 0.22 mmol, 26%). 1H NMR (300 MHz, CDCl3): δ 1.45 (6H, t, J=7.2, OCH2CH3), 4.53 (4H, q, J=7.2, OCH2), 5.07 (2H, s, CH2Cl), 7.78 (1H, dd, J=8.1, 4.5, H11), 8.05 (1H, d, J=8.4, H6), 9.31 (1H, dd, J=4.5, 1.8, H10), 9.50 (1H, dd, J=8.1, 1.8, H12), 9.53 (1H, d, J=8.7, H5). 13C NMR (75 MHz, CDCl3): δ14.4 (CH3), 47.3 (CH2Cl), 63.2 (OCH2), 123.8 (C11), 124.6 (C6), 125.6 (q Ar), 126.6 (q Ar), 134.5 (C12), 135.7 (C5), 140.1 (q Ar), 140.4 (q Ar), 144.3 (q Ar), 144.4 (q Ar), 147.6 (q Ar), 148.1 (q Ar), 153.8 (C10), 161.0 (C7), 165.0 (CO), 165.1 (CO). m/z (ES+) 447 (MNa+).

Source