All Notebooks | Help | Support | About
2nd January 2018 @ 15:20

Reaction scheme snar.jpg

Masses and measurements:

3-(4-bromophenyl)-5-chloro-[1,2,4]triazolo[4,3,a]pyrazine- 0.5627g

3,4-diflurophenylethan-1-ol - 0.370g

NaH - 0.0876g

THF - 15mL

Procedure:

3-(4-bromophenyl)-5-chloro-[1,2,4]triazolo[4,3,a]pyrazine (0.5627g, 1.82mmol) was placed in a RBF and under inert gas, THF (15mL). Still under an inert atmosphere, the 3,4-difluorophenylethan-1-ol (0.370g, 2.34mmol) and the reaction mixture was put under ice, the NaH (0.0876g, 2.19mmol) was added and left to react until TLC analysis confirmed the completion of the reaction. Before the NaH was added the reaction mixture was an orange solution and after addition of the NaH , the reaction mixture turned to a dark brown opaque mixture.

Step 4 reaction mixture.jpg

The reaction was left to react until TLC analysis (1:1 ethyl acetate & petroleum ether) confirmed complete of reaction.

TLC after 3 hours.jpg
                                  
TLC after 20 hours.jpg

Once reaction was complete 2M HCl (20mL) was added to quench reaction and the mixture was seperated and extracted using ethyl acetate (3 x 30mL). Upon seperation, the organic layer was orange and the inorganic layer was a pale yellow colour. The organic layers were kept, dried with MgSO4, filtered under vacuo and rotary evaporated to give a dark brown solid crude material (0.95g).

Filtrate.jpg
                                   
Crude product.jpg

The crude material was run on a flash column (100% ethyl acetate solvent) and TLC analysis confirmed that test tubes 13-30 contained the final product. Test tubes 13-30 were collected in a RBF and rotary evaporated to give a dark green/brown solid product of 3-(4-bromophenethoxy)-[1,2,4]triazolo[4,3,a]pyrazine(0.1318g, 16.79%).

Start of flash column.jpg
                         
Progress of flash column.jpg
                   
End of flash column.jpg

 

 

Attached Files
Reaction scheme snar.jpg
Step 4 reaction mixture.jpg
TLC after 3 hours.jpg
TLC after 20 hours.jpg
Filtrate.jpg
Crude product.jpg
Start of flash column.jpg
Progress of flash column.jpg
End of flash column.jpg