Efficient Role of Mg-ZnCl2 for Selective Reduction of α,β-Unsaturated Carbonyl Compounds in Aqueous Medium.

ChemInform ◽  
2005 ◽  
Vol 36 (29) ◽  
Author(s):  
Anil Saikia ◽  
Madan Gopal Barthakur ◽  
Romesh Chandra Boruah
Keyword(s):  
Aqueous Medium ◽  
Carbonyl Compounds ◽  
Selective Reduction

Efficient Role of Mg-ZnCl2for Selective Reduction of α,β-Unsaturated ­Carbonyl Compounds in Aqueous Medium

Synlett ◽  
2005 ◽  
pp. 523-525 ◽  
Author(s):  
Romesh Chandra Boruah ◽  
Anil Saikia ◽  
Madan Gopal Barthakur
Keyword(s):  
Aqueous Medium ◽  
Carbonyl Compounds ◽  
Selective Reduction

Pseudobase formation in 2-methylpapaverinium cations and their biotransformation by enzymes of rat liver homogenates in vitro

1980 ◽  
Vol 45 (3) ◽  
pp. 956-965 ◽  
Author(s):  
Daniela Walterová ◽  
Vladimír Preininger ◽  
Ladislav Dolejš ◽  
František Grambal ◽  
Miroslav Kyselý ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Aqueous Medium ◽  
Rat Liver ◽  
Carbonyl Compounds ◽  
Liver Enzymes ◽  
Aqueous Ethanol ◽  
Equilibrium Constants ◽  
Liver Homogenates

2-Methylpapaverinium iodide (I), 2'-hydroxymethyl-2-methylpapaverinium iodide (IX), and 2-methyl-3,4-dihydropapaverinium iodide (X. CH3I) form pseudobase by addition of hydroxide ions to the C(1)=N(+) bond. 2'-Hydroxymethyl-2-methyl-3,4-dihydropapaverinium iodide (XV) and 2'-hydroxymethyl-2-methyl-9-oxo-3,4-dihydropapaverinium iodide (XVI) react with hydroxide ions in aqueous medium under formation of cyclic pseudobases XVII and XVIII. The equilibrium constants (KR+) of pseudobase formation have been measured in aqueous ethanol (1 : 1 w/w, 25°C, ionic strength 0.1). The quaternary papaverinium derivatives are metabolized to isoquinilones and carbonyl compounds by means of rat liver enzymes. The role of pseudobases in these biotransformations has been discussed and biogenetic conclusions have been drawn.

scholarly journals Oxidation of Terpenoids to Achieve High-Value Flavor and Fragrances—Questioning Microalgae Oxidative Capabilities in the Biotransformation of the Sesquiterpene Valencene and of Selected Natural Apocarotenoids

Chemistry ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 821-830
Author(s):  
Davide De Simeis ◽  
Stefano Serra ◽  
Alessandro Di Fonzo ◽  
Francesco Secundo
Keyword(s):  
Experimental Data ◽  
Natural Products ◽  
Aqueous Medium ◽  
Photochemical Reaction ◽  
Substrate Oxidation ◽  
Market Size ◽  
Chlorella Sp ◽  
General Opinion ◽  
Natural Way

Natural flavor and fragrance market size is expected to grow steadily due to the rising consumer demand of natural ingredients. This market request is guided by the general opinion that the production of natural compounds leads to a reduction of pollution, with inherent advantages for the environment and people’s health. The biotransformation reactions have gained high relevance in the production of natural products. In this context, few pieces of research have described the role of microalgae in the oxidation of terpenoids. In this present study, we questioned the role of microalgal based oxidation in the synthesis of high-value flavors and fragrances. This study investigated the role of three different microalgae strains, Chlorella sp. (211.8b and 211.8p) and Chlorococcum sp. (JB3), in the oxidation of different terpenoid substrates: α-ionone, β-ionone, theaspirane and valencene. Unfortunately, the experimental data showed that the microalgal strains used are not responsible for the substrate oxidation. In fact, our experiments demonstrate that the transformation of the four starting compounds is a photochemical reaction that involves the oxygen as oxidant. Even though these findings cast a shadow on the use of these microorganisms for an industrial purpose, they open a new possible strategy to easily obtain nootkatone in a natural way by just using an aqueous medium, oxygen and light.

scholarly journals Robust and efficient hydrogenation of carbonyl compounds catalysed by mixed donor Mn(I) pincer complexes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjun Yang ◽  
Ivan Yu. Chernyshov ◽  
Robin K. A. van Schendel ◽  
Manuela Weber ◽  
Christian Müller ◽  
...  
Keyword(s):  
Noble Metal ◽  
Crucial Role ◽  
Carbonyl Compounds ◽  
Catalytic Performance ◽  
Hydrogen Atmosphere ◽  
Pincer Complexes ◽  
Catalyst Activation ◽  
Hydrogenation Catalysts ◽  
Induction Times

AbstractAny catalyst should be efficient and stable to be implemented in practice. This requirement is particularly valid for manganese hydrogenation catalysts. While representing a more sustainable alternative to conventional noble metal-based systems, manganese hydrogenation catalysts are prone to degrade under catalytic conditions once operation temperatures are high. Herein, we report a highly efficient Mn(I)-CNP pre-catalyst which gives rise to the excellent productivity (TOF° up to 41 000 h−1) and stability (TON up to 200 000) in hydrogenation catalysis. This system enables near-quantitative hydrogenation of ketones, imines, aldehydes and formate esters at the catalyst loadings as low as 5–200 p.p.m. Our analysis points to the crucial role of the catalyst activation step for the catalytic performance and stability of the system. While conventional activation employing alkoxide bases can ultimately provide catalytically competent species under hydrogen atmosphere, activation of Mn(I) pre-catalyst with hydride donor promoters, e.g. KHBEt3, dramatically improves catalytic performance of the system and eliminates induction times associated with slow catalyst activation.

scholarly journals Central role of carbonyl compounds in atmospheric chemistry

2000 ◽  
Vol 105 (D15) ◽  
pp. 19771-19778 ◽  
Author(s):  
D. J. Lary ◽  
D. E. Shallcross
Keyword(s):  
Atmospheric Chemistry ◽  
Carbonyl Compounds
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