Cesium carbonate → 8-Methoxy-5-(thiophen-2-yl)-[1,2,4]triazolo[4,3-a]pyrazine

HRID 1045721Notes

Reaction equation

Br[C:2]1[N:7]2[CH:8]=[N:9][N:10]=[C:6]2[C:5]([O:11][CH3:12])=[N:4][CH:3]=1.[S:13]1[CH:17]=[CH:16][CH:15]=[C:14]1B(O)O.C([O-])([O-])=O.[Cs+].[Cs+].O1CCOCC1>C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.O>[CH3:12][O:11][C:5]1[C:6]2[N:7]([CH:8]=[N:9][N:10]=2)[C:2]([C:14]2[S:13][CH:17]=[CH:16][CH:15]=2)=[CH:3][N:4]=1

Participants

Conditions

Temperature: 100 °C

Procedure

A 50 mL round bottom flask was charged with 5-bromo-8-methoxy-[1,2,4]triazolo[4,3-a]pyrazine (0.25 g, 1.1 mmol), thiophen-2-ylboronic acid (280 mg, 2.2 mmol), Pd(PPh3)4 (190 mg, 0.16 mmol), Cs2CO3 (530 mg, 1.6 mmol), 1,4-dioxane (11 mL) and water (4 mL). The resulting mixture was heated under N2 at 100° C. overnight. Work-up: the reaction mixture was filtered. The filter cake was washed with EtOAc (10 mL) and the filtrate was extracted with more EtOAc (10 mL×3). The combined organic solutions were washed with brine, dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel with a 1:50 methanol/dichloromethane, to afford 0.25 g (99%) of the product as a yellow solid. MS m/z: 233 (M+H+).

Workup

filtrationthe reaction mixture was filtered
washThe filter cake was washed with EtOAc (10 mL)
extractionthe filtrate was extracted with more EtOAc (10 mL×3)
washThe combined organic solutions were washed with brine
dry with materialdried over anhydrous Na2SO4
concentrationconcentrated in vacuo
customThe residue was purified by flash column chromatography on silica gel with a 1:50 methanol/dichloromethane

Sources & evidence

ORD record: ord-253db3cef78643d1bb071e927acd7f4c
Source dataset: uspto-grants-2013_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08569300B2

Reaction notes

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