Trimethylsilylacetylene → 2-Bromo-5-trimethylsilanylethynyl-pyrazine

HRID 446759Notes

Reaction equation

HRID 446759 reaction equation
[Br:1][C:2]1[CH:7]=[N:6][C:5](I)=[CH:4][N:3]=1.[C:9]([Si:11]([CH3:14])([CH3:13])[CH3:12])#[CH:10]>[Pd].[Cu]I.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.CN(C=O)C.CCN(CC)CC>[Br:1][C:2]1[CH:7]=[N:6][C:5]([C:10]#[C:9][Si:11]([CH3:14])([CH3:13])[CH3:12])=[CH:4][N:3]=1

Participants

7

Reactant 2

HCID 66111TrimethylsilylacetyleneHCID 219312002-Bromo-5-iodopyrazine

Product 1

HCID 574976862-Bromo-5-trimethylsilanylethynyl-pyrazine

Reagents, catalysts & solvents 4

HCID 23938PalladiumCatalystHCID 24350Copper(1+) iodide; Copper(I) iodide; Cuprous iodide; Cuprous iodide (CuI)CatalystHCID 178418397HCID 178418397, compoundCatalystHCID 22056947triethylamine N,N-dimethylformamideSolvent

Procedure

Reaction of a mixture of 2-bromo-5-iodo-pyrazine and copper (1) iodide under inert conditions in an appropriate solvent and base e.g. DMF/Et3N with ethynyl-trimethyl-silane using a palladium catalyst e.g. Pd(PPh3)4 at room temperature gives 2-Bromo-5-trimethylsilanylethynyl-pyrazine. This material can be used without further purification and reacted to form 6-bromo-2-trimethylsilanyl-pyrazolo[1,5-a]pyrazine using O-(mesitylenesulfonyl)hydroxylamine to form the N-amino adduct. This can then be cyclised by reacting with base e.g. K2CO3 to form pyrazolopyrazine core (Scheme 6).

Sources & evidence

ORD record
ord-c34d6f58a99c472fa4ffd4f8f00f6c89
Source dataset
uspto-grants-2013_07
Patent number
US08481531B2

Reaction notes

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