structures of compounds 4, 8 and 9 have been confirmed by single-crystal X-ray diffraction studies, and their crystal structures are shown to be stabilized by hydrogen bonding. The thermal properties of all the Schiff bases have been studied in air and all of them underwent melting followed by endo- and exothermic decomposition processes to yield an ethanimine (CH3–CH=NH) intermediate which in turn
treatment of acne, a dermatological disorder affecting 650M persons globally. Inhibiting the protease responsible for the cleavage of inactive pro-IL1β into active IL-1β, caspase-1, could be an alternative small molecule approach. This report describes the discovery of uracil 20, a potent (38 nM in THP1 cells assay) caspase-1 inhibitor for the topical treatment of inflammatory acne. The uracil series was designed
(Benzyloxycarbonyl)- and (tert-butoxycarbonyl)hydrazones are easily reduced by sodium cyanoborohydride in acidic medium. The method is an alternative to catalytic hydrogenation and allows ready access to both N-benzyloxycarbonyl and N-tert-butoxycarbonyl protected N′ -alkyl- and N′-arylmethylhydrazines. The products can be isolated as the solid, stable cyanoborane adducts.
One-pot Synthesis of Protected Alkylhydrazines from Acetals and Ketals. Scope and Limitations
作者:Anton Mastitski、Siret Niinepuu、Tõiv Haljasorg、Jaak Järv
DOI:10.1080/00304948.2015.1088760
日期:2015.11.2
Although the protecting groups may be removed by hydrolysis, this additional step could be complicated and indeed, in some cases, has hampered application of the reductive alkylation method. To overcome these difficulties, we devised and reported a one-pot synthesis method for the preparation of protected alkylhydrazines directly from acetals and ketals, without prior conversion to aldehydes or ketones
烷基肼是有机合成中的重要组成部分,它们的 N 保护衍生物用于将 a-氮杂氨基酸掺入肽序列中以获得氮杂肽。这些肽模拟物,其中氨基酸的 aC 原子被氮部分取代,与普通肽保持显着的结构相容性,但对生物降解具有更高的抵抗力。因此氮杂-肽模拟物已被认为是有前途的候选药物。一旦克服了有效合成这些氮杂肽的困难,这个概念肯定会得到更广泛的研究。这些问题还包括氮杂氨基酸前体的制备,其本质上是 N 保护的取代肼。由于这些肼中只有少数可以商业购买,已经设计了两种主要的合成路线来制备取代肼。最常用的方法是用适当的醛或酮对肼进行还原烷基化。第二种方法涉及使用例如卤代烷直接对肼进行烷基化。显然,还原性烷基化是优选的,因为它简单、易得且羰基化合物的成本相对较低;更重要的是,它避免了多烷基化产物的形成。然而,如果醛和/或酮含有带杂原子和/或不饱和取代基的带负电基团,则在醛的情况下,它们易于自缩合和/或快速氧化成羧酸。这使
Diel, Peter J.; Maier, Ludwig, Phosphorus and Sulfur and the Related Elements, 1988, vol. 36, p. 85 - 98