All Notebooks | Help | Support | About
11th September 2016 @ 14:49

 Started on 9/9

scheme

compound

MW (g/mol)

Mol (mmol)

g

Density (g/mL)

Volume (mL)

eqv

2 chloro 6 hydrazinylpyrazine

144.56

4.76

0.6884

 

 

1

toluene

 

 

 

 

13 mL

 

Triethyl orthoformate

148.20

9.52

1.41

0.891

1.58

2

TsOH

172.2

0.476

0.082

 

 

0.1

Product

 154.56

 4.76

 0.736

 

 

 

 

2-chloro-6-hydrazinylpyrazine (from Synthesis of 2-Chloro-6-hydrazinylpyrazine (MRLS 1-1) (0.6884 g, 4.76 mmol) was dissolved in toluene (13 mL). Triethyl orthoformate (1.58 mL, 9.52 mmol) and TsOH (0.082 g, 10 mol %) were added, and the resulting reaction mixture was refluxed at 110 oC for 24 hours.

Procedure based on TM 37-14.

 

Log

 

TLC (labeled TLC crude in data below) was done on the filtered reaction mixture, showing a good amount of starting material remaining. From top to botting, starting material, co spot, product. SiO2 plate, 30% ethyl acetate in hexanes. 1H NMR was done on the crude reaction mixture to compare to HM 1-1. The NMR looks good.


9-13

Column was started, using dry pack to get the product into the column. First eluent was 30% etoac:hexanes, then moved to 50% once the first fraction was off.


Moved to 62.5% etoac:hexanes after that to get the third fraction. Separation was poor.

Once the third fraction was off, moved to pure etoac in an attempt to get the last fraction that didn’t move much at all in 30% on the TLC.


Many attempts to run NMR on this last fraction failed. Etoac was concentrated under reduced pressure yielding an oil, but this oil did not work agreeably with CDCl3, and turned purple in the NMR tube for unknown reasons. There was enough left for another NMR in DMSO, but there was still too much ethyl acetate in the sample for a clean NMR. There were a few aromatic peaks, but the yield was obviously too low to work with. Re-synthesis will be attempted.


One thing to note is that in one of the NMRs with 128 scans and a longer relaxation time, an aldehyde peak did show up, which is consistent with some of the first attempts to synthesize this molecule by Alice, where the intermediate stabilized with an aldehyde as opposed to closing the ring.

Attached Files
LSMR 2-1 proton nmr
14407775_10207617786945616_927225604_n.jpg