distorted amides having both high degree of nitrogen pyramidalization (38–55°) and amide twist (12–30°). In solution they exist in a defined conformation that is evidenced by the presence of a sharp signal of N-methyl protons at low temperature. They do not isomerize in solutions. Some of them slowly undergo the N-O bond scission above 100 °C. Both isomers are not as sensitive to neutral hydrolysis as twisted
使用二硫烷(方法 A)或二苯基硫代膦酰氯(方法 B)对 N-甲基对取代苯异羟肟酸进行硫代膦酰化,仅提供相应 O-硫代磷酰衍生物的一种构象异构体(X 射线和 NMR 分析)。进行 P-转酰胺氧基化反应是硫代膦酰化可逆性的证据。只有那些在芳酰基残基中含有强 EWG 取代基或在磷原子上含有大取代基的产物才具有 E 构象。DFT 计算证实了每个异构体的能量支配。Z-异构体是扭曲的酰胺,具有高度的氮锥化(38-55°)和酰胺扭曲(12-30°)。在溶液中,它们以确定的构象存在,低温下 N-甲基质子的尖锐信号的存在证明了这一点。它们在溶液中不会异构化。其中一些在 100 °C 以上缓慢发生 NO 键断裂。两种异构体对中性水解均不像扭曲酰胺那样敏感,并且对胺呈惰性。碱性水解的速率可以与异羟肟酸的 pKa 相关联。由于它们出色的亲氧性,这些化合物可以被定义为神经毒剂替代品和氟化磷的更安全替代品,用于丝氨酸活性酶抑制研究。
Protective coating compostition
申请人:Nederlandse Organisatie voor Toegepast
-Natuurwetenschappelijk Onderzoek TNO
公开号:EP2425878A1
公开(公告)日:2012-03-07
The invention is directed to a coating composition comprising a curable compound and an N-alkylated hydroxamic acid. A coating composition of the invention can suitably be used to provide an object with a coating, wherein the coating forms a protective layer that can degrade organophosphates and thiophosphates. A coating (obtained after curing the coating composition) of the invention is in particular effective in degrading organophosphate and thiophosphates due to the N-alkylated hydroxamic acid according to formula (1) being able to function as a catalyst.