- Scalable anti-Markovnikov hydrobromination of aliphatic and aromatic olefins
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To improve access to a key synthetic intermediate we targeted a direct hydrobromination-Negishi route. Unsurprisingly, the anti-Markovnikov addition of HBr to estragole in the presence of AIBN proved successful. However, even in the absence of an added initiator, anti-Markovnikov addition was observed. Re-examination of early reports revealed that selective Markovnikov addition, often simply termed "normal" addition, is not always observed with HBr unless air is excluded, leading to the rediscovery of a reproducible and scalable initiator-free protocol.
- Galli, Marzia,Fletcher, Catherine J.,Del Pozo, Marc,Goldup, Stephen M.
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supporting information
p. 5622 - 5626
(2016/07/06)
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- Synthesis of pharmacologically relevant indoles with amine side chains via tandem hydroformylation/fischer indole synthesis
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The sequence of hydroformylation and Fischer indole synthesis starting from amino olefins and aryl hydrazines is described. In a convergent manner, the two units bearing pharmacologically relevant substituents are assembled in the final indolization step. This modular and diversity-oriented approach to tryptamines and homotryptamines can be conducted in water and allows synthesis of branched and nonbranched tryptamines as well as tryptamine-based pharmaceuticals such as the 5-HT1D agonist L 775 606.
- Schmidt, Axel M.,Eilbracht, Peter
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p. 5528 - 5535
(2007/10/03)
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- DIARYL ETHERS AS OPIOID RECEPTOR ANTAGONIST
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A compound of the formula (I) wherein the variables X1 to X10, R1 to R7 including R3', E, v, y, z, A and B are as described, or a pharmaceutically acceptable salt, solvate, enantiomer, racemate, diastereomer or mixtures thereof, useful for the treatment, prevention or amelioration of obesity and Related Diseases is disclosed.
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Page/Page column 69
(2008/06/13)
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- Substituted 4-aminocyclohexanol compounds
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4-aminocyclohexanol compounds, processes for their preparation, pharmaceutical formulations comprising these compounds and the use of substituted 4-aminocyclohexanol compounds for the preparation of pharmaceutical formulations and for the treatment of div
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- The effect of vinyl esters on the enantioselectivity of the lipase-catalysed transesterification of alcohols
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The enantioselectivity of the lipase from Pseudomonas cepacia (PCL) in the transesterification of 2-phenyl-1-propanol 1 was studied using a series of vinyl 3-arylpropanoates as acyl donors. The most enantioselective transesterification reaction of the alcohol was attained by using vinyl 3-(p-iodophenyl)- or 3-(p-trifluoromethylphenyl)propanoates, with enantiomer ratios, E, of 116 and 138, respectively. Vinyl 3-phenylpropanoate was also effective for the resolution of 1 mediated by lipases from P. fluorescens and porcine pancreas and for the PCL-catalysed transesterification of several 2-phenyl-1-alkanols. The enantiomeric resolution of 1 was practically carried out by the first enantioselective transesterification using PCL and vinyl 3-(p-iodophenyl)propanoate to afford (R)-1 and then the enantioselective hydrolysis of the resultant ester to afford (S)-1.
- Kawasaki, Masashi,Goto, Michimasa,Kawabata, Shigeki,Kometani, Tadashi
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p. 585 - 596
(2007/10/03)
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- Substituted 1-indolylpropyl-4-phenethylpiperazadine derivatives
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A class of 1-?3-(1H-indol-3-yl)propyl!-4-(2-phenylethyl) piperazine derivatives, substituted at the 5-position of the indole nucleus by a five-membered heteroaromatic moiety, and on the phenyl ring of the phenethyl moiety by fluoro, chloro, trifluoromethyl, alkoxy or an oxazolidinone group and optionally by one or two further substituents, are selective agonists of 5-HT1 -like receptors, being potent agonists of the human 5-HT1D α receptor subtype while possessing at least a 10-fold selective affinity for the 5-HT1D α receptor subtype relative to the 5-HT1D α subtype; they are therefore usefull in the treatment and/or prevention of clinical conditions, in particular migraine and associated disorders, for which a subtype-selective agonist of 5-HT1D receptors is indicated, while eliciting fewer side-effects, notably adverse cardiovascular events, than those associated with non-subtype-selective 5-HT1D receptor agonists.
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- Thermodynamic Stabilities of Phenonium Ions Based on Bromide-Transfer Equilibria in the Gas Phase
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The thermodynamic stabilities of the phenonium (ethylenebenzenium) ion and ring-substituted derivatives were determined based on the bromide-transfer equilibria in the gas phase. It has been shown that the phenonium ion is 2.4 kcal mol-1 more stable than the t-butyl cation, and that the substituent effect on its stability can be correlated with the Yukawa-Tsuno equation with a ρ value of -12.6 and an r+ of 0.62. An r+ value smaller than unity of the α-cumyl(1-methyl-1-phenylethyl) cation suggested that π-delocalization in the phenonium ion is essentially less effective than through a benzylic π-interaction. On the other hand, the ρ value of -12.6 is distinctly larger than that for the ordinary benzylic carbocation systems, but is comparable to that of the benzenium ion. In addition, it has been found that the r+ value of the phenonium ions in the gas phase is in complete agreement with that for the aryl-assisted process in the acetolysis of 2-arylethyl toluenesulfonates. This suggests that the degree of π-delocalization of the positive charge is the same in the transition state and the intermediate cation. It is concluded that an r+ value of 0.6, which is ranked at a unique position in the continuous spectrum of the resonance demand, is characteristic of the bridged structure of the phenonium ion intermediate and the transition state.
- Mustanir,Mishima, Masaaki,Fujio, Mizue,Tsuno, Yuho
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p. 1401 - 1407
(2007/10/03)
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- REACTIONS OF DIHALOCARBENES WITH SUBSTITUTED SPIROHEPTA-4,6-DIENES
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Reactions of dihalocarbenes with spirohepta-4,6-diene lead to the formation of 1-halo-3-(2-haloethyl)benzenes, which readily undergo dehydrohalogenation to 3-halostyrenes.From 1-arylspirohepta-4,6-dienes and dihalocarbenes 3-halostilbenes are obtained.
- Molchanov, A. P.,Kostikov, R. R.
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p. 935 - 937
(2007/10/02)
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