Reaction #165809

Reaction equation

POCl3

4-[5-amino-6-[[(3-methoxythiophene-2-carbonyl)amino]carbamoyl]pyrazin-2-yl]-N,N-dimethyl-benzamide

→

product

Yield 23.0%

4-(5-amino-6-(5-(3-methoxythiophen-2-yl)-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-N,N-dimethylbenzamide

Yield 23.0%

Solvents

dichloromethane

CH2Cl2

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was cooled to room temperature
2. 2
   workup.WAITThe mixture was left
3. 3
   workup.STIRRINGto stir at room temperature for 20 min
4. 4
   Otherthe layers separated
5. 5
   ExtractionThe aqueous layer was extracted further with dichloromethane (2×5 mL)
6. 6
   Dryingcombined organics dried over MgSO4
7. 7
   Concentrationconcentrated in vacuo
8. 8
   OtherSolid obtained
9. 9
   Otherpurified by column chromatography on the ISCO column companion system (12 g column, 0-5% MeOH/ CH2Cl2)
10. 10
    Concentrationconcentrated in vacuo
11. 11
    OtherThis was purified further by reverse phase preparative HPLC [Waters Sunfire C18, 10 mM, 100 Å column, gradient 10%-95% B (solvent A: 0.05% TFA in water; solvent B: CH3 CN) over 16 minutes at 25 mL/min]
12. 12
    Otherfreeze dried

Procedure

TBTU (160.4 mg, 0.4995 mmol) and Et3N (33.70 mg, 46.42 μL, 0.3330 mmol) were added to a solution of 4-(5-amino-6-(hydrazinecarbonyl)pyrazin-2-yl)-N,N-dimethylbenzamide (100 mg, 0.3330 mmol) and 3-methoxythiophene-2-carboxylic acid (52.67 mg, 0.3330 mmol) in CH2Cl2 (2.000 mL) and the resulting solution stirred at room temperature for 72 h. The reaction mixture was diluted with dichloromethane (5 mL) and water (5 mL) and the layers separated. The aqueous layer was extracted further with dichloromethane (3×5 mL), and the combined organic extracts dried over MgSO4, filtered and concentrated in vacuo to leave 4-[5-amino-6-[[(3-methoxythiophene-2-carbonyl)amino]carbamoyl]pyrazin-2-yl]-N,N-dimethyl-benzamide as a yellow oil. POCl3 (1.788 g, 1.087 mL, 11.66 mmol) was added to 4-[5-amino-6-[[(3-methoxythiophene-2-carbonyl)amino]carbamoyl]pyrazin-2-yl]-N,N-dimethyl-benzamide and the resulting mixture heated at 100° C. for 2 h. The reaction mixture was cooled to room temperature and ice/water added carefully with vigourous stirring between additions. The mixture was left to stir at room temperature for 20 min and then diluted with dichloromethane (10 mL) and the layers separated. The aqueous layer was extracted further with dichloromethane (2×5 mL) and combined organics dried over MgSO4 and concentrated in vacuo. Solid obtained is re-dissolved in CH2Cl2 and purified by column chromatography on the ISCO column companion system (12 g column, 0-5% MeOH/ CH2Cl2). Product fractions were combined and concentrated in vacuo. This was purified further by reverse phase preparative HPLC [Waters Sunfire C18, 10 mM, 100 Å column, gradient 10%-95% B (solvent A: 0.05% TFA in water; solvent B: CH3 CN) over 16 minutes at 25 mL/min]. The product fractions were combined and freeze dried to give the product as a yellow solid (33.0 mg, 23% yield) 1H NMR (400 MHz, DMSO) d 2.98 (s, 3H), 3.01 (s, 3H), 4.07 (s, 3H), 7.30 (d, 1H), 7.56 (d, 2H), 7.70 (br s, 2H), 7.96 (d, 1H), 8.14 (d, 2H) and 8.97 (s, 1H) ppm; MS (ES+) 423.19

Source