All Notebooks | Help | Support | About
29th November 2013 @ 10:23

Methyl 4-oxy-2-pyrazinecarboxylate (5.08 g) was dissolved in SOCl2 (35.52 ml). The reaction was heated to reflux (100 oc) for 17 hours and then allowed to cool to ambient temperatire. The  SOCl2 was removed under pressure and the brown oil residue was quenched by dropwise addition of water (34.82 ml) at 0oc. The mixture was neutralised with addition of 1M K2CO3 (aq) and extracted with CH2Cl2 (5 x 69.64 ml). The organic layer was collected and TLC was carried out of the organic layer vs product (6/7 solid of EO 6-1) vs the aqueous layer (EO TLC 6-2A) NMR of the oil was derived (EO 6-2B 1H NMR)

The oil was purified by silica gel chromatography (5% Et2OAc in DCM) using the product from 6/7 in EO 6-1 as the desired product refrence. Sample 3/4 showed significant product in the presence of another material (EO TLC sample 3,4) so was collected. Samples 5-9 shoowed purely products spots (EO TLC sample 5-9 and EO TLC sample 5-9 cont'd) Samples 10 - 21 did not show product spots but consistent spots of another isomer (EO TLC sample 10-21 and EO TLC sample 10-21 cont'd) Solvent was removed from Each collected sample and the NMR was derived for each sample. EO 6-C DMSO 1H NMR for sample 3/4,  EO 6-D DMSO 1H NMR for sampleS 5-9 and  EO 6-E chloroform 1H NMR for sample 10-21.

Attached Files
28th November 2013 @ 14:19

 

To a well stirred solution of AEW DS 2-1 (100 mg, 0.38 mmol), 2-methyltetrahydrofuran (6 mL), Chloramine-T (123 mg, 0.54 mmol) and TFA (one drop)was added and the resulting reaction mixture was stirred at 75oC for 1.5h.

The reaction mixture was then allowed to cool to room temperature, and the organic phase washed with 10 wt% aq. sodium sulphite solution (10mL) and 2M dilute sodium hydroxide (3 x 10 mL) and then evaporated to dryness. An NMR of the product was taken. NMR showed that there was no product present and no further improvement of the yield and the experiment was taken no further. 

Data:

 

Hazard and Risk Assessment:

8-1.doc

NMR:

NovIII-01608_10_1.pdf
Attached Files
27th November 2013 @ 10:54

Methyl 2-pyrazinecarboxylate (5.10 g) was suspended in 1,2 - dichloroethane (50.80 ml) and mCPBA (16.43 g) was added. The reaction was stirred at 60 oC for 18 hours. The reaction was allowed to cool to room tmperature sand diluted with CH2Cl2 (152 ml). The percipitate was filtered off and washed with additional CH2Cl2 (3 x 17.80 ml). The filtrate was combines, dried over K2CO3, filtered and concentrated under vacuum. The residue was suspended in hexane (25.40 ml). the product was isolated using filtration, washed with additional hexane (2 x 25.40 ml) to afford a light yellow solid (9.46 g) 1H NMR was dervived (EO 5-2A 1H NMR) NMR showed m-CPBA present so sample was purified.

Solid was washed with addition of Et2OAc (250 ml) which was then wahsed with NaHCO3 (250 ml). This wash was done three times and TLC'ed against product (EO 5-1) in 5% Et2OAc in DCM (EO TLC 5-2A) TLC showed that product was still present in the aqueous layer so three additional washes of the aqueous layer was carried out with DCM (250 ml) and methanol (50 ml) TLC was taken (EO TLC 5-2B). TLC showed most of the product had left aquous layer so all the collected organic layers were collected and solvent was removed under pressure to give a solid (5.08 g) (xxxd yield) NMR of the purified solid was derived (EO 5-2B 1H NMR).

 

Linked Posts
Attached Files
26th November 2013 @ 10:25

 

To a well stirred solution of AEW DS 2-1 (100 mg, 0.38 mmol), 2-methyltetrahydrofuran (6 mL), Chloramine-T (123 mg, 0.54 mmol) and one drop of glacial acetic acid was added and the resulting reaction mixture was stirred at 75oC for 1.5h.

The reaction mixture was then allowed to cool to room temperature, and the organic phase washed with 10 wt% aq. sodium sulphite solution (10mL) and 2M dilute sodium hydroxide (3 x 10 mL) and then evaporated to dryness. An NMR of the product was taken. NMR showed that there was no further improvement to the amount of product produced and the reaction was not taken any further forward.

Data:

3ORProject10_DS7-1_271113_1H_dl400.tar

Hazard and Risk Assessment:

5-1.doc

NMR:

NMR DS 7-1.pdf
Attached Files
25th November 2013 @ 15:06

 

To a well stirred solution of AEW DS 2-1 (100 mg, 0.38 mmol), 2-methyltetrahydrofuran (6 mL) and Chloramine-T (123 mg, 0.54 mmol) was added and the resulting reaction mixture was stirred at 60oC for 24h.

The reaction mixture was then allowed to cool to room temperature, and the organic phase washed with 10 wt% aq. sodium sulphite solution (10mL) and 2M dilute sodium hydroxide (3 x 10 mL) and then evaporated to dryness. An NMR of the product was taken. NMR determined that there was no improvement on the amount of product formed, and the experiment was taken no further.

 

Data:

3ORProject10_DS6-1_261113_1H_dl400.tar

Hazard and Risk Assessment:

5-1.doc

NMR:

DS 6-1.pdf

 

Attached Files