- Fluorinations of unsymmetrical diaryliodonium salts containing: Ortho -sidearms; Influence of sidearm on selectivity
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Activated aromatics were reacted with two different fluoroidoane reagents 1 and 2 in the presence of triflic acid to prepare only the para-substituted diaryliodonium salts. With fluoroiodane 1 the unsymmetrical diaryliodonium salts contained an ortho-propan-2-ol sidearm, whereas the alcohol sidearm was eliminated to form an ortho-styrene sidearm in the reaction with fluoroiodane 2. Only the diaryliodonium salts containing a styrene sidearm were fluorinated successfully to deliver para-fluorinated aromatics in good yields.
- Abudken, Ahmed M. H.,Hope, Eric G.,Singh, Kuldip,Stuart, Alison M.
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p. 6140 - 6146
(2020/10/30)
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- Transition-metal-free decarboxylative bromination of aromatic carboxylic acids
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Methods for the conversion of aliphatic acids to alkyl halides have progressed significantly over the past century, however, the analogous decarboxylative bromination of aromatic acids has remained a longstanding challenge. The development of efficient methods for the synthesis of aryl bromides is of great importance as they are versatile reagents in synthesis and are present in many functional molecules. Herein we report a transition metal-free decarboxylative bromination of aromatic acids. The reaction is applicable to many electron-rich aromatic and heteroaromatic acids which have previously proved poor substrates for Hunsdiecker-type reactions. In addition, our preliminary mechanistic study suggests that radical intermediates are not involved in this reaction, which is in contrast to classical Hunsdiecker-type reactivity. Overall, the process demonstrates a useful method for producing valuable reagents from inexpensive and abundant starting materials.
- Quibell, Jacob M.,Perry, Gregory J. P.,Cannas, Diego M.,Larrosa, Igor
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p. 3860 - 3865
(2018/04/26)
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- Phenyl acetate derivatives, fluorine-substituted on the phenyl group, as rapid recovery hypnotic agents with reflex depression
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We report the synthesis of novel, potentially hypnotic fluorine-substituted phenyl acetate derivatives. We describe the structure-activity relationship that led us to the promising derivative: ethyl 2-(4-(2-(diethylamino)-2-oxoethoxy)-5-ethoxy-2-fluorophenyl) acetate (55). The unique pharmacological features of compound 55 are its relatively high affinity for the GABAA receptor, together with a unique affinity for the NMDA receptor, different to propanidid and AZD3043. In animal models, compound 55 showed stronger hypnotic potency and longer duration of LORR than propanidid and AZD3043, but also maintained a rapid recovery time to walking and behavioral recovery. In particular, compound 55 displayed reflex depression during infusion.
- Zhang, Heng,Xu, Xiangqing,Chen, Yin,Qiu, Yinli,Liu, Xin,Liu, Bi-Feng,Zhang, Guisen
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p. 524 - 539
(2014/12/11)
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- Synthesis and biological evaluation of naphthyl phenyl ethers (NPEs) as novel nonnucleoside HIV-1 reverse transcriptase inhibitors
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A novel series of naphthyl phenyl ether analogues (NPEs) have been synthesized and evaluated for their in vitro activities against HIV in C8166 cells. Most of the compounds exhibited moderate to excellent anti-HIV activities. Among them the most active co
- Gu, Shuang-Xi,Zhang, Xuan,He, Qiu-Qin,Yang, Liu-Meng,Ma, Xiao-Dong,Zheng, Yong-Tang,Yang, Shi-Qiong,Chen, Fen-Er
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experimental part
p. 4220 - 4226
(2011/08/09)
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- Study on the electronic effect on coordinating donors in heptacoordinate trichlorogermanes
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Trichloro[tris(2,5-dimethoxyphenyl)methyl]germane (1a), trichloro[tris(3-fluoro-6-methoxyphenyl)methyl]germane (1b), and trichloro[tris(2-methoxy-5-trifluoromethylphenyl)methyl]germane (1c) were synthesized. X-ray crystallographic analyses of 1a-c revealed their heptacoordinate geometries around the germanium atoms. The interatomic distances between the oxygen atoms and the central germanium atoms in the crystalline state were not significantly affected by change of functional groups on the benzene rings, while the optimized structures by theoretical calculations and Atoms in Molecules (AIM) analysis indicated linear relationship between the donating ability of functional groups and the O?Ge interatomic interactions.
- Iwanaga, Kohei,Kobayashi, Junji,Kawashima, Takayuki
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p. 10127 - 10132
(2008/02/13)
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- UROKINASE INHIBITORS
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Disclosed are benzothiophene and thienothiophene derivatives useful for inhibiting urokinase activity.
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- 107. Substitution electrophile aromatique dans l'anhydride sulfureux liquide. Etude cinetique de la reaction de bromination d'anisoles monosubstitues. Transmission des effets electroniques et caracteristiques de l'etat de transition
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Reactivity-structure correlations for anisole and eleven of its substituted derivatives established from bromination rate constants in liquid SO2, unlike observations in water, show the reaction to be highly sensitive to substituent effects, (ρ+H2O = -7.1; ρ+SO2 = -10.51).This result is ascribed to the solvation of the methoxy group which decreases the conjugation of para-substituted (ρ+O = -9.70) compared to that of ortho-substituted derivatives (ρ+p = -8.86).The highly solvated transition state lies far from reactants on the reaction coordinate and the positive charge developed in this state is nearly unity.
- Castellonese, Paul,Villa, Pierre
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p. 1068 - 1077
(2007/10/02)
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- N-Bromosuccinimide (NBS) Bromination of Anisole and p-Substituted Anisoles in 50percent Aqueous Acetic Acid
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The kinetics of bromination of anisole and p-substituted anisoles by NBS was investigated in the presence of HClO4/NaOAc and Hg(OAc)2 in 50percent aq.HOAc.Pure NBS bromination can be followed by initial addition of Hg(OAc)2, which prevents accumulation of bromine in the system.The reaction is catalysed by AgClO4.Based on Hammett plot, the reaction constant is -7.85 for Ag+-catalysed bromination.As the water content in aq.HOAc is increased from 0-60percent (v/v), the rate constant is found to increase 20 fold for PNA-NBS reaction.The product analysis of the PNA-NBS reaction catalysed by Ag+ was done by glc which gave 2-bromo-4-nitroanisole as the only product.
- Srinivasan, S. P.,Gnanapragasam, N. S.
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p. 953 - 957
(2007/10/02)
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