Heterogeneously catalysed synthesis of primary amines by direct amination of alcohols with ammonia has long been an elusive goal. In contrast to reported Ru-based catalytic systems, we report that Ru–MgO/TiO2 acts as an effective heterogeneous catalyst for the direct amination of a variety of alcohols to primary amines at low temperatures of ca. 100 °C without the introduction of H2 gas. The present
通过醇与氨的直接胺化而异质催化合成伯胺一直是一个遥不可及的目标。与报道的基于Ru的催化体系相反,我们报道Ru–MgO / TiO 2是一种有效的非均相催化剂,可在约20 ℃的低温下将多种醇直接胺化成伯胺。100°C,不引入H 2加油站。本系统可应用于多种醇,并为引起人们关注的生物单体2,5-双(氨基甲基)呋喃(BAMF)提供了有效的合成途径。可以通过使用MgO调节Ru–H物种的反应性来合理化高催化性能。光谱测量表明,MgO通过从MgO向Ru供电子而增强了氢化物物种的反应性。
Mechanism of anodic cleavage of benzyl ethers
作者:Jean W. Boyd、Paul W. Schmalzl、Larry L. Miller
DOI:10.1021/ja00531a030
日期:1980.5
Hydrogen atom abstraction from C–H bonds of benzylamides by the aminoxyl radical BTNO: A kinetic study
aminoxyl radical BTNO (benzotriazole-N-oxyl; >N–O˙) is generated from HBT (1-hydroxybenzotriazole; >N–OH) by oxidation with a CeIV salt. BTNO presents a broad absorption band with λmax 474 nm that lends itself to investigate the kinetics of H-abstraction from H-donor substrates by spectrophotometry. Thus, rate constants (kH) of H-abstraction by BTNO from CH2-groups α to the nitrogen atom in X-subs
氨氧自由基BTNO(苯并三唑-N-氧基;> N–O˙)是由HBT(1-羟基苯并三唑; > N–OH),通过Ce IV盐氧化。BTNO具有最大λmax 474 nm的宽吸收带,因此可以通过分光光度法研究从H供体底物上吸H的动力学。因此,已经在MeCN中确定了BTNO从CH 2-基团α到氮原子在X-取代的-(N-乙酰基)苄胺(XC 6 H 4 CH 2 NHCOCH 3)中吸氢的速率常数(k H)。溶液在25°C。所述的相关性ķ ħ X与哈米特σ数据+参数为ρ(-0.65)给出一个较小的值,该值与基本H提取步骤兼容。来自适当氘代的酰胺底物的动力学同位素效应的相当大的值(k H / k D = 8.8)进一步证实了H的吸收是决定速率的因素。每当可裂开的C–H键与酰胺部分的氮孤对或相邻的芳族基团共线时,就可以通过立体电子效应加快H吸收的相关性,已获得证据。据报道,对Ar CH 2 NHCOMe中苄基CH键的离解能值进行了评估。
Iridium‐Catalysed C(sp3)−H Activation and Hydrogen Isotope Exchange via Nitrogen‐Based Carbonyl Directing Groups
作者:Nathan Knight、James Thompson、John Andrew Parkinson、David Lindsay、Tell Tuttle、William Kerr
DOI:10.1002/adsc.202400156
日期:——
the first two FDA-approved deuterated pharmaceutical compounds (Scheme 1B).4, 5 The widespread use of the hydrogen isotopes, deuterium (2H or D) and tritium (3H or T), is due in no small part to advances in the synthetic accessibility of these isotopologues. In particular, installation via hydrogen isotope exchange (HIE)6, 7 allows the late-stage incorporation of deuterium or tritium, and avoids time-consuming