2,5-Bis-(sulfonyl)pyrazines as unprecedented building blocks and their SNAr reactions

Previously unknown 2,5-bis-sulfonylpyrazines are prepared and their SNAr reactions are investigated. When 2 equiv of thiols are employed, the corresponding bis-thiopyrazines are obtained exclusively. However, phenols or alkoxides gave rise to only the corresponding mono-substituted aryloxy- or alkoxy-sulfonylpyrazines in excellent yields. A carbon nucleophile prepared by treating malonate with NaH also produced the corresponding mono-sulfonylpyrazines. Aliphatic amines and anilines only provided the mono-anilino-sulfonylpyrazines in poor to moderate yields.