Quaternary Carbons
Quaternary Carbons - Related Videos
07:50
Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
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2019
A simple and practical protocol for the efficient conjugate addition of functionalized monoorganozinc bromides to cyclic α,β-unsaturated carbonyls to furnish all-carbon quaternary centers was developed.
09:41
Isolation of Quartz Grains for Optically Stimulated Luminescence (OSL) Dating of Quaternary Sediments for Paleoenvironmental Research
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Cited by 4 •
2021
This protocol is for the isolation of quartz grains by size for luminescence dating of sediments. Outlined are physical cleansing and chemical digestions by soaking sequentially in H2O2, HCl, HF, and HCl again to isolate quartz grains. The quartz purity is quantified with microscopic assessment, Raman spectroscopy, and IR depletion ratio.
05:18
Quaternary Structure Modeling Through Chemical Cross-Linking Mass Spectrometry: Extending TX-MS Jupyter Reports
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Cited by 2 •
2021
Targeted cross-linking mass spectrometry creates quaternary protein structure models using mass spectrometry data acquired using up to three different acquisition protocols. When executed as a simplified workflow on the Cheetah-MS web server, the results are reported in a Jupyter Notebook. Here, we demonstrate the technical aspects of how the Jupyter Notebook can be extended for a more in-depth analysis.
02:21
Globular and Fibrous Proteins
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2020
Many proteins can be classified into two distinct subtypes - globular or fibrous. These two types differ in their shapes and solubilities. Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...
09:36
Safety Precautions and Operating Procedures in an (A)BSL-4 Laboratory: 4. Medical Imaging Procedures
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Cited by 8 •
2016
Here, we present an overview of the preparation and animal handling procedures required to safely perform medical imaging in an animal biosafety level 4 laboratory. Computed tomography of a mock-infected guinea pig illustrates these procedures that may be used to evaluate the disease caused by a high consequence pathogen.
FAQs
Steric crowding can restrict the space available around a quaternary carbon and influence the bond angles formed by its four sigma bonds. These spatial effects may also alter conformational preferences, meaning the molecule favors some three-dimensional arrangements over others. Examining this local crowding helps chemists understand how a highly substituted center shapes the structure and behavior of neighboring groups.
Although the quaternary center itself has no attached hydrogen, its crowded tetrahedral environment can influence groups positioned nearby. Steric interactions may change how those groups are oriented and how readily they participate in chemical transformations. Consequently, recognizing the center provides structural context when interpreting why neighboring sites display particular reactivity patterns in an organic molecule.
Alkylation and coupling reactions can generate quaternary carbons by adding carbon-carbon bonds to an already substituted framework. These transformations are important because they construct highly substituted molecular architectures rather than merely modifying existing groups. In synthetic planning, identifying the desired quaternary center helps relate the target structure to the carbon-carbon bond-forming steps needed to assemble it.
Chemists examine the molecular structure to locate tetrahedral carbon centers connected to four carbon atoms, then use that information alongside systematic naming and NMR interpretation. Because these centers carry no attached hydrogen, their absence of directly bonded hydrogen is an important analytical feature. Combining structural inspection with NMR data supports more reliable assignments in complex organic molecules.
Quaternary carbons occur in natural products, pharmaceuticals, and complex synthetic targets, where their crowded three-dimensional arrangements contribute to the overall architecture of the molecule. Mapping these centers helps researchers describe and analyze complicated structures accurately. Their presence also makes carbon-carbon bond construction and structural interpretation relevant when studying molecules designed for biological or medicinal applications.
Recognizing quaternary carbons gives chemists a clearer picture of substitution, three-dimensional shape, and local steric environment within a molecule. That information supports systematic naming, structural analysis, and planning of carbon-carbon bond-forming reactions. In complex molecular design, accurately accounting for these centers helps connect the intended framework with the synthetic route and the structure ultimately obtained.