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09-06-2016, First step in synthesis of the hetero-oxadiazole, reaction of 2-6 dichloropyrazine with malononitrile, following procedure from Nikishkin et al (2013)
09-11-2016, Work up of the second attempt at step 1
09-23-2016. Step 1 redo, on 5 gram scale
09-24-2016. Work up of 09-23-2016
09-29-2016, work up and purification of [4]
09/28/2016 Step 4, on a larger scale this time. Conversion of methyl 6-chloropyrazine-2-carboxylate [3] to methyl 6-hydrazineylpyrazine-2-carboxylate [4] using hydrazine according to AEW 85-5
10/07/2016 GC mass spec characterization of rxn from [4]->[5]
10/18/16: Trial work up of reaction of 6-chloropyrazinecarbonitrile and hydrazine
10/4/16: Trial of Step 4:Product [4] to Product [5]
10/6/16: Trial Synthesis of 6-hydrazinelypyrazine-2-carbonitrile and from 6- hydrazinelypyrazine-2-carboximidhydrazide from chloropyrazinecarbonitrile
9/12/16 Step 2 in synthesis. Going from [2]->[3]
9/13/16: Work-up of product [3] and TLC plates
9/15/16: Second Synthesis of Methyl 6-chloropyrazine-2-carboxylate [product 3]
9/18/16-9/20/16: Trial Synthesis of Methyl 6-hydrazineylpyrazine-2-carboxylate (Product 4)
9/22/16: Inconclusive Trial Synthesis of Methyl 6-hydrazineylpyrazine-2-carboxylate (Product 4)
9/25/16-9/27/16: Synthesis of Product 3, methyl 6-chloropyrazine-2-carboxylate
9/27/2016 Late Night
9/29/2016 HNMR of product 4, and HNMR of product 4 after D2O exchange 01/10/2016
9/8/16-Continued Synthesis of 2-(6-chloropyrazin-2(1H)-ylidene)malononitrile
CNMR so far
HNMR so far, of all relevant compounds
The Synthetic scheme of Hetero-oxadiazole Synthesis
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18th September 2016 @ 23:23

Since the reaction of product 2 (6-Chloro-2(1H)-pyrazinylidene)malononitrile)with Li2CO3 and MMPP worked (except for the presence of the impurity), we decided to use the rest of product 2 and complete this reaction again. 0.3895 grams of product 2 was dissolved in 22.90 mL of Methanol, and then .2447 g of Li2CO3 was added. The solution turned from bright red to bright yellow. After 30 minutes, the reaction flask was placed in an ice bath and 1.012 grams of MMPP was added. There was no immediate color change, but when we returned to the reaction after 3 hours the solution was a milky white color. After vacuum filtration, the volatiles from the filtrate were removed by rotary evaporation. The solid that remained looked like a conglomeration of yellow crystals. The solution was partitioned between 10 mL of H20 and 10 mL CHCl3, and the organic phase was dried over MgSO4. Cotton in the bottom of a glass funnel was used to remove the MgSO4. We combined the resulting solution with the other solid product 3 from the previous experiment (9/13/16). Once dissolved, we passed the solution over a very small column of silica. In total

tlc_tubes2-7.png
11 fractions were taken. We did a quick check to see which fractions had product by spotting each of them on a silica plate then visualizing with UV (Not pictured). All tubes were UV active except fraction 1. Subsequently, we conducted TLC with fractions 2-7 (TLC Plate 3) and fractions 8-11 (TLC Plate 4). Fractions 2 and 3 showed completely pure product, and fraction 4 only showed a tiny amount of impurity. The rest of the fractions showed both product 3 and the impurity. Fractions 2 and 3 were pooled and the volatiles were evaporated. The resulting mass of product 3 was .0892g.

 

Citations

Nikishkin, Nicolai I. et al. "Pyrazine-Functionalized Calix[4]Arenes: Synthesis By Palladium-Catalyzed Cross-Coupling With Phosphorus Pronucleophiles And Metal Ion Extraction Properties". New J. Chem. 37.2 (2013): 391-402. Web. 4 Sept. 2016. .

Attached Files
prod3scheme.png
TLC Plate 3
TLC Plate 4