- Allylsilane-interrupted homo-Nazarov cyclization and synthesis of bicyclo[3.2.1]octan-8-ones
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The combination of homo-Nazarov cyclization of 2-(tert- butyldiphenylsilylmethyl)cyclopropyl vinyl ketone leading to oxyallyl cation and its subsequent [3+2] capture by allylsilane has been demonstrated as an useful strategy for the construction of functionalized bicyclo[3.2.1]octan-8-ones. The [3+2] capture proceeds exclusively in the exo mode to make the overall reaction diastereoselective. The less substituted end of the oxyallyl cation was found to react nearly two times faster than the more substituted end.
- Yadav, Veejendra K.,Naganaboina, Vijaya K.,Hulikal, Vijaykumar
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supporting information
p. 2015 - 2018
(2014/04/03)
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- Synthesis, characterization and antioxidant activity of angiotensin converting enzyme inhibitors
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Angiotensin converting enzyme (ACE) catalyzes the conversion of angiotensin I (Ang I) to angiotensin II (Ang II). ACE also cleaves the terminal dipeptide of vasodilating hormone bradykinin (a nonapeptide) to inactivate this hormone. Therefore, inhibition of ACE is generally used as one of the methods for the treatment of hypertension. 'Oxidative stress' is another disease state caused by an imbalance in the production of oxidants and antioxidants. A number of studies suggest that hypertension and oxidative stress are interdependent. Therefore, ACE inhibitors having antioxidant property are considered beneficial for the treatment of hypertension. As selenium compounds are known to exhibit better antioxidant behavior than their sulfur analogues, we have synthesized a number of selenium analogues of captopril, an ACE inhibitor used as an antihypertensive drug. The selenium analogues of captopril not only inhibit ACE activity but also effectively scavenge peroxynitrite, a strong oxidant found in vivo. The Royal Society of Chemistry 2011.
- Bhuyan, Bhaskar J.,Mugesh, Govindasamy
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experimental part
p. 1356 - 1365
(2011/04/23)
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- Study of a lipophilic captopril analogue binding to angiotensin I converting enzyme
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Human ACE is a central component of the renin-angiotensin system and a major therapeutic target for cardiovascular diseases. The somatic form of the enzyme (sACE) comprises two homologous metallopeptidase domains (N and C), each bearing a zinc active site with similar but distinct substrate and inhibitor specificities. In this study, we present the biological activity of silacaptopril, a silylated analogue of captopril, and its binding affinity towards ACE. Based on the recently determined crystal structures of both the ACE domains, a series of docking calculations were carried out in order to study the structural characteristics and the binding properties of silacaptopril and its analogues with ACE.
- Dalkas, Georgios A.,Marchand, Damien,Galleyrand, Jean-Claude,Martinez, Jean,Spyroulias, Georgios A.,Cordopatis, Paul,Cavelier, Florine
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experimental part
p. 91 - 97
(2010/11/05)
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- An improved synthesis of captopril
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An improved synthesis of captopril using methacrylic acid as the starting material is described. Treatment of methacrylic acid (I) with a hydrogen halide gave the 3-halogeno-2-methylpropanoic acids II and III, which were treated with thionyl chloride to yield the corresponding 3-halogeno-2-methylpropanoyl chlorides IV and V. Treatment of IV or V with L-proline yielded the N-(R,S-3-halogeno-2-methylpropanoyl)-L-prolines VI and VII, which were separated into optically pure R- and S-diastereoisomers using dicyclohexylamine. Treatment of halides of VI or VII with methanolic ammonium hydrosulfide gave captopril in 28% yield.
- Nam,Lee,Ryu
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p. 1843 - 1844
(2007/10/02)
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- Process for the preparation of 1-[3-mercapto-(2S)-methylpropionyl]-pyrrolidine-(2S)-carboxylic acid
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The invention relates to a novel process for the preparation of 1-[3-mercapto-(2S)-methylpropionyl]-pyrrolidine-(2S)-carboxylic acid through the N-acylation of L-proline. According to the process of the invention L-proline is acylated with a 3-halogen-2-methylpropionyl chloride of the formula III STR1 wherein Hal is a halogen atom, preferably chlorine or bromine, the obtained 1-[3-halogen-(2S)-methylpropionyl]-pyrrolidine-(2S)-carboxylic acid, wherein Hal is as stated above, is reacted with an alkali thiosulfate or alkali trithiocarbonate and the reaction product is hydrolized with an acid. The process of the invention is very economical as compared with the known processes. The desired product is prepared from methacrylic acid in 4 reaction steps with a total yield of 25 percent and from L-proline in 2 reaction steps with a total yield of 30 percent.
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