Divergent Selectivity in MgI<sub>2</sub>-Mediated Ring Expansions of Methylenecyclopropyl Amides and Imides
作者:Mark Lautens、Wooseok Han
DOI:10.1021/ja011110o
日期:2002.6.1
the reaction site in the dienolate with aryl aldimines and aldehydes as well as the size of the ring. Excellent divergent selectivity to five- vs. six-membered heterocycles is observed: alpha-alkylation/5-exo-tet cyclization (Z = NPh(2)) vs. gamma-alkylation/6-exo-trig cyclization (Z = 2-oxazolidone). Analogously, the reaction of the MCP imide with alkyl aldimines demonstrates the same selectivity by
Synthesis of phosphonate derivatives of methylenecyclopropane nucleoside analogues by alkylation–elimination method and unusual opening of cyclopropane ring
作者:Hui-Ping Guan、Yao-Ling Qiu、Mohamad B. Ksebati、Earl R. Kern、Jiri Zemlicka
DOI:10.1016/s0040-4020(02)00589-6
日期:2002.7
were then used for alkylation–elimination of nucleic acid bases (adenine) or precursors (2-amino-6-chloropurine and N4-acetylcytosine). The intermediary Z+E-isomers 22a+23a and 22b+23b were dealkylated with bromo- of iodotrimethylsilane to free phosphonicacids 15a, 16a and phosphonate with an open cyclopropane ring 25 which were separated by ion exchange chromatography on Dowex 1. Phosphonate diesters
The Toxicity of Methylenecyclopropylglycine: Studies of the Inhibitory Effects of (Methylenecyclopropyl)formyl-CoA on Enzymes Involved in Fatty Acid Metabolism and the Molecular Basis of Its Inactivation of Enoyl-CoA Hydratases
作者:Ding Li、Gautam Agnihotri、Srikanth Dakoji、Eugene Oh、Marily Lantz、Hung-wen Liu
DOI:10.1021/ja991908w
日期:1999.10.1
(Methylenecyclopropyl)formyl-CoA (MCPF-CoA), a toxic metabolite of methylenecyclopropylglycine (MCPG), is known to have hypoglycemic activity due to its ability to interrupt the β-oxidation pathway of fatty acid metabolism. Earlier experiments have shown that acetoacetyl-CoA thiolase, 3-ketoacyl-CoA thiolase, acyl-CoA dehydrogenases, and enoyl-CoA hydratase (ECH) are cellular targets that can be inhibited
(亚甲基环丙基)甲酰基-CoA (MCPF-CoA) 是亚甲基环丙基甘氨酸 (MCPG) 的一种有毒代谢物,由于其能够中断脂肪酸代谢的 β-氧化途径,因此已知具有降血糖活性。早期的实验表明,乙酰乙酰辅酶 A 硫解酶、3-酮酰基辅酶 A 硫解酶、酰基辅酶 A 脱氢酶和烯酰辅酶 A 水合酶 (ECH) 是可被 MCPF-CoA 和/或 MCPG 抑制的细胞靶点。为了获得有关靶标特异性和作用方式的更多见解,我们对 MCPF-CoA 对参与脂肪酸代谢的各种酶的影响进行了详细研究。我们的研究证实,MCPF-CoA 是 ECH 的有效灭活剂,但对本研究中测试的其他 β-氧化酶几乎没有影响。
(<i>R</i>)-(−)- and (<i>S</i>)-(+)-Synadenol: Synthesis, Absolute Configuration, and Enantioselectivity of Antiviral Effect
作者:Yao-Ling Qiu、Andrew Hempel、Norman Camerman、Arthur Camerman、Fiona Geiser、Roger G. Ptak、Julie M. Breitenbach、Toshiko Kira、Ling Li、Elizabeth Gullen、Yung-Chi Cheng、John C. Drach、Jiri Zemlicka
DOI:10.1021/jm980323u
日期:1998.12.1
(S)-(+)-synadenol (2a). Absolute configuration of 1a was established by two methods: (i) synthesis from (R)-methylenecyclopropanecarboxylic acid (8) and (ii) X-ray diffraction of a single crystal of (-)-synadenol hydrochloride. Racemic methylenecyclopropanecarboxylic acid (10) was resolved by a modification of the described procedure. The R-enantiomer 8 was converted to ethyl ester 13 which was brominated to give
Rotational Spectroscopy of 1-Cyano-2-methylenecyclopropane (C<sub>5</sub>H<sub>5</sub>N)─A Newly Synthesized Pyridine Isomer
作者:Dairen R. Jean、Samuel A. Wood、Brian J. Esselman、R. Claude Woods、Robert J. McMahon
DOI:10.1021/acs.jpca.3c08002
日期:2024.2.29
The gas-phase rotational spectrum of 1-cyano-2-methylenecyclopropane (C1, C5H5N), an isomer of pyridine, is presented for the first time, covering the range from 235 to 500 GHz. Over 3600 a-, b-, and c-type transitions for the ground vibrational state have been assigned, measured, and least-squares fit to partial-octic A- and S-reduced distorted-rotor Hamiltonians with low statistical uncertainty (σfit
首次给出了吡啶异构体1-氰基-2-亚甲基环丙烷( C 1 , C 5 H 5 N)的气相旋转光谱,覆盖范围为235至500 GHz。超过 3600 个基振动态的a 、 b和c型跃迁已被指定、测量,并且最小二乘拟合到具有低统计不确定性的部分八次 A 和 S 减少的扭曲转子哈密顿量(σ拟合) = 42 kHz)。两个最低能量基本态(ν 27和ν 26 )和最低能量泛音(2ν 27 )的跃迁已被类似地测量、分配,并且最小二乘拟合到单态哈密顿量。使用 B3LYP 和 MP2 水平的理论计算出的振动-旋转相互作用常数 ( B 0 – B v ) 与相应的实验值进行了比较。根据我们的初步分析,接下来的几个振动激发态通过科里奥利和非简谐耦合形成一个或多个相互作用态的复杂多聚体。这里提出的光谱常数和过渡频率构成了未来实验室光谱学和天文搜索 1-氰基-2-亚甲基环丙烷的基础。