Hydrogen abstraction in astrochemistry: formation of ˙CH2CONH2 in the reaction of H atom with acetamide (CH3CONH2) and photolysis of ˙CH2CONH2 to form ketene (CH2CO) in solid para-hydrogen

2020 ◽  
Vol 22 (11) ◽  
pp. 6192-6201 ◽  
Author(s):  
Karolina Anna Haupa ◽  
Wei-Siong Ong ◽  
Yuan-Pern Lee
Keyword(s):  
Organic Molecules ◽  
Hydrogen Abstraction ◽  
Amide Bond ◽  
Para Hydrogen ◽  
Hydrogen Exposure ◽  
Complex Organic

The amide bond of acetamide is unaffected by hydrogen exposure, but the hydrogen abstraction on its methyl site activates this molecule to react with other species to extend its size as a first step to form interstellar complex organic molecules.

Thermal and photochemical study of CH3OH and CH3OH–O2 astrophysical ices

2020 ◽  
Vol 500 (1) ◽  
pp. 1188-1200
Author(s):  
Killian Leroux ◽  
Lahouari Krim
Keyword(s):  
Interstellar Medium ◽  
Organic Compounds ◽  
Organic Molecules ◽  
Uv Light ◽  
Hydrogen Abstraction ◽  
Insertion Reaction ◽  
Abstraction Reaction ◽  
Uv Photons ◽  
Astrophysical Ices ◽  
Complex Organic

ABSTRACT Methanol, which is one of the most abundant organic molecules in the interstellar medium, plays an important role in the complex grain surface chemistry that is believed to be a source of many organic compounds. Under energetic processing such as ultraviolet (UV) photons or cosmic rays, methanol may decompose into CH4, CO2, CO, HCO, H2CO, CH3O and CH2OH, which in turn lead to complex organic molecules such as CH3OCHO, CHOCH2OH and HOCH2CH2OH through radical recombination reactions. However, although molecular oxygen and its detection, abundance and role in the interstellar medium have been the subject of many debates, few experiments on the oxidation of organic compounds have been carried out under interstellar conditions. The present study shows the behaviour of solid methanol when treated by UV light and thermal processing in oxygen-rich environments. Methanol has been irradiated in the absence and presence of O2 at different concentrations in order to study how oxidized complex organic molecules may form and also to investigate the O-insertion reaction in the C–H bound to form methanediol HOCH2OH through a CH3OH + O(1D) solid-state reaction. The adding of O2 in the thermal and photochemical reaction of solid methanol leads to the formation of O3, H2O and HO2, in addition to three main organics, HCOOH, CHOCHO and HOCH2OH. We show that in an O2-rich environment, species such as CO, CH4, HCO, CH3OH and CHOCH2OH are oxidized into CO2, CH3OH, HC(O)OO, HOCH2OH and CHOCHO, respectively, while HCOOH might be formed through the H2CO + O(3P) → (OH + HCO)cage → HCOOH hydrogen-abstraction reaction.

Imine as a Linchpin Approach for Distal C(sp2)–H Functionalization

2020 ◽  
Author(s):  
Sukdev Bag ◽  
Sadhan Jana ◽  
Sukumar Pradhan ◽  
Suman Bhowmick ◽  
Nupur Goswami ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Bond Activation ◽  
Bond Formation ◽  
Ancillary Ligand ◽  
Significant Challenge ◽  
Site Selectivity ◽  
Directing Group ◽  
Covalently Linked ◽  
Complex Organic ◽  
Post Functionalization

<p>Despite the widespread applications of C–H functionalization, controlling site selectivity remains a significant challenge. Covalently attached directing group (DG) served as an ancillary ligand to ensure proximal <i>ortho</i>-, distal <i>meta</i>- and <i>para</i>-C-H functionalization over the last two decades. These covalently linked DGs necessitate two extra steps for a single C–H functionalization: introduction of DG prior to C–H activation and removal of DG post-functionalization. We introduce here a transient directing group for distal C(<i>sp<sup>2</sup></i>)-H functionalization <i>via</i> reversible imine formation. By overruling facile proximal C-H bond activation by imine-<i>N</i> atom, a suitably designed pyrimidine-based transient directing group (TDG) successfully delivered selective distal C-C bond formation. Application of this transient directing group strategy for streamlining the synthesis of complex organic molecules without any necessary pre-functionalization at the distal position has been explored.</p>

scholarly journals A Sustainable Improvement of ω-Bromoalkylphosphonates Synthesis to Access Novel KuQuinones

Organics ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 107-117
Author(s):  
Mattia Forchetta ◽  
Valeria Conte ◽  
Giulia Fiorani ◽  
Pierluca Galloni ◽  
Federica Sabuzi
Keyword(s):  
Metal Oxides ◽  
Phosphonic Acid ◽  
Organic Molecules ◽  
Building Blocks ◽  
Reaction Conditions ◽  
Phosphonic Acids ◽  
Sustainable Improvement ◽  
Phosphonate Esters ◽  
First Time ◽  
Complex Organic

Owing to the attractiveness of organic phosphonic acids and esters in the pharmacological field and in the functionalization of conductive metal-oxides, the research of effective synthetic protocols is pivotal. Among the others, ω-bromoalkylphosphonates are gaining particular attention because they are useful building blocks for the tailored functionalization of complex organic molecules. Hence, in this work, the optimization of Michaelis–Arbuzov reaction conditions for ω-bromoalkylphosphonates has been performed, to improve process sustainability while maintaining good yields. Synthesized ω-bromoalkylphosphonates have been successfully adopted for the synthesis of new KuQuinone phosphonate esters and, by hydrolysis, phosphonic acid KuQuinone derivatives have been obtained for the first time. Considering the high affinity with metal-oxides, KuQuinones bearing phosphonic acid terminal groups are promising candidates for biomedical and photo(electro)chemical applications.

scholarly journals Not Just Transporters: Alternative Functions of ABC Transporters in Bacillus subtilis and Listeria monocytogenes

2021 ◽  
Vol 9 (1) ◽  
pp. 163
Author(s):  
Jeanine Rismondo ◽  
Lisa Maria Schulz
Keyword(s):  
Bacillus Subtilis ◽  
Listeria Monocytogenes ◽  
Abc Transporters ◽  
Organic Molecules ◽  
Atp Hydrolysis ◽  
The Past ◽  
Wide Range ◽  
Regulatory Functions ◽  
Complex Organic ◽  
Detoxification Mechanisms

ATP-binding cassette (ABC) transporters are usually involved in the translocation of their cognate substrates, which is driven by ATP hydrolysis. Typically, these transporters are required for the import or export of a wide range of substrates such as sugars, ions and complex organic molecules. ABC exporters can also be involved in the export of toxic compounds such as antibiotics. However, recent studies revealed alternative detoxification mechanisms of ABC transporters. For instance, the ABC transporter BceAB of Bacillus subtilis seems to confer resistance to bacitracin via target protection. In addition, several transporters with functions other than substrate export or import have been identified in the past. Here, we provide an overview of recent findings on ABC transporters of the Gram-positive organisms B. subtilis and Listeria monocytogenes with transport or regulatory functions affecting antibiotic resistance, cell wall biosynthesis, cell division and sporulation.

Complex Organic Molecules Formation in Space Through Gas Phase Reactions: A Theoretical Approach

2017 ◽  
Vol 836 (2) ◽  
pp. 240 ◽  
Author(s):  
Pilar Redondo ◽  
Carmen Barrientos ◽  
Antonio Largo
Keyword(s):  
Gas Phase ◽  
Theoretical Approach ◽  
Organic Molecules ◽  
Gas Phase Reactions ◽  
Complex Organic

ChemInform Abstract: SEARCH FOR SUPERRADIANT EMISSION FROM ′COMPLEX′ ORGANIC MOLECULES IN THE VAPOR PHASE

1974 ◽  
Vol 5 (32) ◽  
Author(s):  
R. PAPPALARDO ◽  
S. L. SHAPIRO ◽  
S. AHMED ◽  
R. ALFANO
Keyword(s):  
Vapor Phase ◽  
Organic Molecules ◽  
Complex Organic

Electrochemical Radical C(sp3)-H Arylation of Xanthenes with Electron-Rich Arenes

2022 ◽  
Author(s):  
Bin Wei ◽  
Jing-Hao Qin ◽  
Yong-Zheng Yang ◽  
Ye-Xiang Xie ◽  
Xuan-Hui Ouyang ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Bond Formation ◽  
Carbon Bond ◽  
Carbon Carbon Bond ◽  
Complex Organic

C(sp3)-H arylation has recently emerged as a powerful straegy for complex organic molecules synthesis through a new carbon-carbon bond formation. We herein describe an efficient electrochemical C(sp3)-H arylation of xanthenes...

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