铁死亡是一种以铁依赖性脂质过氧化为标志的非细胞凋亡形式的细胞死亡1,在器官损伤、退行性疾病和治疗耐药性癌症的脆弱性2中起着关键作用。尽管在理解与铁死亡相关的分子过程方面取得了实质性进展,但决定细胞对铁死亡敏感性的其他细胞外在和细胞内在过程仍然未知。在这里,我们展示了维生素 K 的完全还原形式——一组萘醌,包括甲萘醌和叶绿醌3-除了通过作为 γ-谷氨酰羧化酶的辅因子与血液凝固相关的常规功能外,还具有强大的抗铁死亡功能。铁死亡抑制蛋白 1 (FSP1) 是一种 NAD(P)H-泛醌还原酶,是继谷胱甘肽过氧化物酶 4 4,5之后控制铁死亡的第二大支柱,被发现可有效地将维生素 K 还原为其氢醌,一种有效的自由基捕获抗氧化剂和(磷酸)脂质过氧化抑制剂。FSP1 介导的维生素 K 减少也是维生素 K 对华法林中毒的解毒作用的原因。由此可见,FSP1 是介导典型维生素 K 循环6中抗华法林维生素 K 减少的酶
Intramolecular benzannulation reactions of manganese carbene complexes
作者:Bonnie L. Balzer、Martine Cazanoue、M. G. Finn
DOI:10.1021/ja00048a076
日期:1992.10
Here we report that intramolecularbenzannulationreactions of siloxycarbene compounds of manganese bearing tethered alkynes produce functionalized naphtoquinones in efficient fashion with complete regioselectivity under photochemical conditions.
Intramolecular Benzannulation Reactions of Chromium Siloxycarbene Complexes: Regiochemical Control and the "Xenochemical Effect" of Alkyne Additives
作者:Michael F. Gross、M. G. Finn
DOI:10.1021/ja00103a007
日期:1994.11
Acetylenic alcohols are attached to chromium oxycarbene fragments via dialkylsilicon linkages in convenient fashion to provide siloxycarbene complexes which undergo intramolecular benzannulation upon heating. Yields of alkynol-derived quinone products after oxidative workup increase markedly when the reactions are conducted in the presence of the ''external'' alkynes diphenylacetylene, 3-hexyne, or 1-hexyne. The action of alkyne additives, which participate in competitive intermolecular benzannulation to only a minor extent, is inhibited by donor solvent or carbon monoxide. Kinetics measurements demonstrate that the benzannulation reactions are initiated by dissociative CO loss. The alkyne additives are believed tb act by coordination to vinylcarbene intermediates produced by intramolecular alkyne insertion, consistent with previous suggestions. A carbon-tethered analogue was found to be unresponsive to the addition of external alkyne. Evidence for the reversible nature of alkyne insertion and the bimolecular decomposition of siloxycarbene complexes is discussed. The methodology provides products with complete regiospecificity regardless of the size of the tethered alkyne substituents, including those not directly accessible by intermolecular reactions of terminal alkynes.