An Efficient Conversion of Phenolic Esters to Benzothiazoles under Mild and Virtually Neutral Conditions
作者:Asit K. Chakraborti、Santosh Rudrawar、Gurmeet Kaur、Lalima Sharma
DOI:10.1055/s-2004-829089
日期:——
Phenolic esters are efficiently converted to 2-substituted benzothiazoles in a one-pot reaction by treatment with 2-aminothiophenol in the presence of a catalytic amount of K2CO3 in N-methyl-2-pyrrolidone (NMP) at 100 °C.
在 100 °C 的 N-甲基-2-吡咯烷酮(NMP)中,在一定量的 K2CO3 催化下,通过与 2-氨基苯硫酚的一锅反应,酚酯可高效地转化为 2-取代的苯并噻唑。
Palladium-Catalyzed External-CO-Free Carbonylation of Aryl Bromides Using 2,4,6-Trichlorophenyl Formate
作者:Hideyuki Konishi、Tomoyuki Sekino、Kei Manabe
DOI:10.1248/cpb.c18-00042
日期:2018.5.1
A practical Pd-catalyzed carbonylation of (hetero)arylbromides using a crystalline carbon monoxide (CO) surrogate, 2,4,6-trichlorophenyl formate (TCPF), was developed. This reaction proceeds without the slow addition technique that was previously required and with a low catalyst loading (1 mol%). The utility of this Pd-catalyzed external-CO-free carbonylation using TCPF was demonstrated in the synthesis
Studies of hydrogen isotope scrambling during the dehalogenation of aromatic chloro‐compounds with deuterium gas over palladium catalysts
作者:William J.S. Lockley、Niccolò A. E. Venanzi、Georgie J. Crane
DOI:10.1002/jlcr.3878
日期:2020.11
catalyst with one prepared in situ by reduction of palladium trifluoroacetate with deuterium gas and dispersed upon micronised polytetrafluoroethylene led to much reduced scrambling (typically 0–6% compared with up to 40% for palladium on carbon) and to high atom% abundance, regiospecific labelling. The improved catalytic system now enables efficient polydeuteration via the dehalogenation of polyhalogenated
使用同位素氢气对芳族卤化物进行催化脱卤是标记药物、生物化学品、环境试剂等的重要策略。为了扩展、改进和进一步了解这一过程,在四氢呋喃溶液中使用氘气和钯碳催化剂对模型芳基氯进行催化氘代脱卤过程中,对氘同位素与氚的扰乱进行了研究。富电子氯芳烃环的加扰程度最大。四氢呋喃溶剂和三乙胺碱不是不想要的朊的来源;相反,它主要来自催化剂的水含量,尽管其他来源的朊也可能存在于催化剂上。用一种制备的催化剂代替 Pd/C 催化剂通过用氘气原位还原三氟乙酸钯并分散在微粉化聚四氟乙烯上,可显着减少乱序(通常为 0-6%,而碳载钯最高可达 40%)和高原子百分比丰度,区域特异性标记。改进后的催化系统现在可以通过多卤化前体的脱卤实现高效的多氘化,使该过程可用于制备 MS 内标,并可能用于高比活性氚标记。
Trichlorophenyl Formate: Highly Reactive and Easily Accessible Crystalline CO Surrogate for Palladium-Catalyzed Carbonylation of Aryl/Alkenyl Halides and Triflates
作者:Tsuyoshi Ueda、Hideyuki Konishi、Kei Manabe
DOI:10.1021/ol302593z
日期:2012.10.19
The high utility of 2,4,6-trichlorophenyl formate, a highly reactive and easilyaccessible crystalline CO surrogate, is demonstrated. The decarbonylation with NEt3 to generate CO proceeded rapidly at rt, thereby allowing external-CO-free Pd-catalyzed carbonylation of aryl/alkenyl halides and triflates. The high reactivity of the CO surrogate enabled carbonylation at rt and significantly reduced the