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8th September 2014 @ 05:44

First attempt at regioselective bromination of the core triazolopyrazine from TM 37, on the road to diversification. Using conditions from patent AU2012269818A1.

 

Starting material was recovered, with small amount of probable product observable by NMR. To be repeated, with continuous/long reflux conditions.

 

scheme

 

5-chloro-[1,2,4]triazolo[4,3-a]pyrazine (from Repeat synthesis of 5-chloro-[1,2,4]triazolo[4,3-a]pyrazine (TM 37-13): 100 mg, 0.65 mmol) was combined with N-bromosuccinimide (196 mg, 0.72 mmol, 1.1 eq) in chloroform (5 mL), and refluxed for 4 h. The reaction mixture was then stirred for 18 h at rt, diluted with chloroform (10 mL), washed with sat. NaHCOsolution (5 mL), and extracted with chloroform (5 x 5 mL). The combined organic layers were concentrated under reduced pressure to give 200 mg crude product as an orange solid. However, by NMR this seems to be almost entirely unreacted triazolopyrazine:

1H (DMSO, 200 MHz)

TM 57-1 1H DMSO 200 MHz.pdf

TM 57-1.zip

Peaks at 9.70, 9.45, 8.17 correspond to starting material; 9.40 and 8.08 (minor) presumable to product fomation. Also, residual NBS (or possibly just succinimide) at 11.06, 2.56.

 

HIRAC:

HIRAC.pdf
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Attached Files
scheme.png
HIRAC.pdf
TM 57-1 1H DMSO 200 MHz.pdf
TM 57-1.zip
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