Grignard Reagent-Mediated Conversion of an Acyl Nitroso-anthracene Cycloadduct to a Nitrone

An intramolecular hetero-Diels−Alder cycloadduct of an acyl
nitroso compound and a 9,10-dimethyl anthracene derivative
was prepared as a potential nitroxyl (HNO) donor. This
compound did not release HNO under any of the conditions
tested. Treatment of this cycloadduct with excess MeMgCl
resulted in the formation of a nitrone, whose structure was
confirmed by X-ray crystallography. A mechanism where
MeMgCl acts as a nucleophile, strong base, and Lewis acid
possibly explains the formation of this product.

本研究制备得到酰基亚硝基化合物（acyl nitroso compound）与9,10-二甲基蒽衍生物（9,10-dimethyl anthracene derivative）的分子内杂原子Diels-Alder环加成产物（intramolecular hetero-Diels−Alder cycloadduct），该产物被用作潜在硝酰基（nitroxyl，HNO）供体。然而在所有测试条件下，该化合物均未释放HNO。以过量MeMgCl（甲基氯化镁）处理该环加成产物后，生成了一种硝酮（nitrone）类化合物，其结构经X射线晶体学（X-ray crystallography）确证。研究提出，MeMgCl可同时充当亲核试剂（nucleophile）、强碱（strong base）与路易斯酸（Lewis acid），该反应机理可合理解释上述产物的生成。