(Press-News.org) LA JOLLA, CA— A new “molecular editing” technique from Scripps Research enables chemists to add new elements to organic molecules at locations that were previously out of reach.
The researchers described their new method in a paper that appeared on May 31, 2023, in Nature. The method uses a designer molecule called a ligand that helps a palladium-atom catalyst reach from one side of a carbon-atom ring to break a carbon-hydrogen bond on the other side, allowing a new set of molecules to join at that site. This molecule-building feat was previously impossible for so-called “saturated” rings of carbon atoms, which are common features in drug molecules.
“Previously, to achieve the same result, one would have to undertake a de novo approach —what we call a cyclization reaction—involving the formation of a new ring structure from an acyclic chain, using this new method, we can directly modify an existing ring to avoid a cyclization process that can often prove challenging,” says study senior author Jin-Quan Yu, PhD, the Bristol Myers Squibb Endowed Chair in Chemistry and the Frank and Bertha Hupp Professor in the Department of Chemistry at Scripps Research. “In addition to saving steps, this unprecedented synthetic strategy can introduce new chemical space for drug discovery as structurally distinct substrates are incorporated into the ring.”
Yu and his laboratory are already renowned for their innovations in C-H functionalization, which is a powerful way of building complex organic molecules to make new pharmaceuticals and other valuable commercial compounds. In this approach, chemists use ligands and catalysts to disconnect a hydrogen (H) atom from a carbon (C) atom at a desired position on an organic molecule. This disconnection allows a new cluster of molecules, known as a functional group, to bond where the hydrogen atom had been.
Most molecules that are used to build new drugs include rings of carbon atoms, also called carbocycles. Thanks in part to Yu’s group, the C-H functionalizations of carbon atoms on these rings have become relatively easy in many cases. This approach is often not applicable, though, in cases where the existing functional group needed to anchor the ligand and catalyst is directly across the ring from the desired C-H functionalization site.
“We call this scenario ‘crossing the river,’ and it has been extremely challenging because the palladium catalyst must form a strained ‘bridge’ connecting the existing functional group and the desired carbon site on the other side of the ring,” Yu says.
The most challenging cases are those in which the carbon-ring structures are “saturated,” which means their carbons are connected only with single carbon-carbon bonds. Saturated carbon rings are common in pharmaceutical chemistry, but are harder targets for C-H functionalization, in part because the C-H bonds have less affinity for metal catalysts, compared to the double C-C bonds of unsaturated carbon rings. The Yu lab has achieved C-H functionalization across unsaturated rings, but there has been no way to do this across a saturated ring—until now.
In the study, Yu and his team, including co-first authors Guowei Kang, PhD, Daniel Strassfeld, PhD, and Tao Sheng, PhD, all postdoctoral research associates in the Yu lab, were able—after months of trial and error—to develop quinuclidine-pyridone and sulfonamide-pyridone ligands enabling cross-ring functionalization with saturated carbon rings. They showed that the approach can work for rings containing from four to eight carbon atoms, within a wide variety of molecules.
The researchers demonstrated the new technique by easily functionalizing molecules that are being used to develop future drugs, including compounds called histone deacetylase inhibitors, which are under investigation as potential cancer treatments.
“We anticipate that this new tool will greatly simplify the synthesis of a large class of carbocyclic molecules used in pharmaceutical chemistry, expanding chemical space for the discovery of new and better drugs,” Yu says.
“Transannular C–H Functionalization of Cycloalkane Carboxylic Acids” was co-authored by Guowei Kang, Daniel Strassfeld, Tao Sheng, Chia-Yu Chen and Jin-Quan Yu, all of Scripps Research.
The research was supported by grants from the National Institute of General Medical Sciences (2R01GM084019 and F32GM143921).
END
Crossing the ring: new method enables C-H activation across saturated carbocycles
Scripps Research chemists add another powerful tool to their “molecular editing” toolkit for crafting pharmaceuticals and other valuable compounds
2023-05-31
ELSE PRESS RELEASES FROM THIS DATE:
How much nitrogen does corn get from fertilizer? Less than farmers think
2023-05-31
URBANA, Ill. — Corn growers seeking to increase the amount of nitrogen taken up by their crop can adjust many aspects of fertilizer application, but recent studies from the University of Illinois Urbana-Champaign show those tweaks don’t do much to improve uptake efficiency from fertilizer. That’s because, the studies show, corn takes up the majority of its nitrogen – about 67% on average – from sources occurring naturally in soil, not from fertilizer.
The evidence for ...
UC Irvine-led study finds Medicaid telemedicine coverage boosted use, healthcare access
2023-05-31
Irvine, Calif., May 31, 2023 – Medicaid telemedicine coverage between 2013 and 2019 was associated with significant growth in telemedicine use and improved healthcare access, while private policies did not have such an association, according to a study led by the University of California, Irvine.
An analysis of 20,000 records of U.S. adults under 65 with either state-level Medicaid or private policies showed that live video chats increased by 6 percentage points and that the ability to consistently access necessary care increased by 11 percentage points for Medicaid patients.
Recently ...
NIRISS instrument on Webb maps an ultra-hot Jupiter’s atmosphere
2023-05-31
There’s an intriguing exoplanet out there – 400 light-years out there – that is so tantalising that astronomers have been studying it since its discovery in 2009. One orbit for WASP-18 b around its star that is slightly larger than our Sun takes just 23 hours. There is nothing like it in our Solar System. A new study led by Université de Montréal Ph.D. student Louis-Philippe Coulombe about this exoplanet, an ultra-hot gas giant 10 times more massive than Jupiter, based on new data from the Canadian NIRISS instrument on the James Webb Space Telescope (JWST) holds many surprises!
Mapping an exoplanet
An ...
Tracking early signs of Alzheimer’s pathology in a mouse model
2023-05-31
Philadelphia, May 31, 2023 – About two-thirds of the risk for Alzheimer’s disease (AD) is thought to arise from genetic influences, but about a third could be influenced by environment and lifestyle, opening the door for behavioral interventions that could delay or prevent pathophysiological changes that occur with AD. Now a new study in a mouse model of AD examines the effects of environmental enrichment on AD symptom progression and pathology. The study appears in Biological Psychiatry, published by Elsevier.
Gerd ...
New study highlights need for expanded application of prism adaptation treatment for spatial neglect
2023-05-31
East Hanover, NJ. May 31, 2023. A team of rehabilitation researchers discovered that prism adaptation therapy (PAT) was as beneficial for treating right-sided spatial neglect as left-sided spatial neglect in a cohort of individuals with stroke and traumatic and non-traumatic brain injuries. These novel findings and their clinical implications were reported in, “Prism adaptation treatment for right-sided and left-sided spatial neglect: A retrospective case-matched study,” (doi: 10.1016/j.arrct.2023.100263). The article was published open access on March 23, 2023, by the Archives of Rehabilitation Research and Clinical Translation. ...
Improving access to quality patient information
2023-05-31
In general, there is an issue around the quality of information about lupus on the internet. Rumours, unchecked data, and unconfirmed research all contribute to confusion and anxiety, and can lead to people taking the wrong actions for themselves and their disease. There is therefore a need for access to quality information about lupus.
Therapeutic patient education (TPE) is a key way to help people self-manage chronic conditions such as lupus. An essential component of TPE is access to valid information ...
Physiotherapy in your pocket
2023-05-31
Apps have become ubiquitous in many parts of life, including for health. For people with an RMD, personalized video exercises (PEV) may be useful to support rehabilitation and physical exercise.
In an abstract shared at the 2023 EULAR annual congress, Davergne and colleagues explore the effectiveness of PEV provided through Apps in supporting rehabilitation for people with disability. The impact was measured in terms of a range of outcomes, including the effect on functional capacity, confidence in exercise performance, use of care, health-related quality of life, adherence, and adverse events.
Data ...
CV risk in psoriatic arthritis
2023-05-31
“This evidence suggests that inflammation in PsA is not limited to skin and joints, but also involves the cardiovascular system”, says Nienke Kleinrensink, lead author on the abstract shared in a session on Comorbidities in RMD at the 2023 EULAR congress in Milan, Italy.
The new finding is based on work done at UMC Utrecht in the Netherlands. Part of the study was funded by Pfizer and Health Holland. The main objective was to investigate whether vascular inflammation is elevated in PsA patients. The team used positron emission tomography/computed tomography (PET/CT) in 75 people with PsA with active peripheral arthritis, ...
Cardiovascular considerations in RA
2023-05-31
The increased cardiovascular risks in RA include acute coronary syndromes (ACS). The extent to which DMARD-induced remission could reduce the risk of ACS in RA versus rates in the general population – and whether there are DMARD-specific beneficial effects on ACS risk – remain unknown. In a session titled, From hearts to lungs: comobidities in RA, Delcoigne and colleagues present new data on the risk of ACS in patients with RA who attained remission with methotrexate (MTX) or a tumor necrosis factor inhibitor (TNFi).
The researchers defined and pooled cohorts of RA patients from registers in Norway and Sweden. This included 14,488 treatment courses ...
A closer look into axial spondyloarthritis
2023-05-31
There is a large diagnostic delay for people with axial spondyloarthritis (axSpA). In 2008, the SPACE cohort started to assess the prevalence of axSpA – and the reliability of an early diagnosis in people with chronic back pain (CBP). Everyone taking part was under the age of 45, and with recent-onset CBP (over 3 months, and up to 2 years) of unknown origin. Now, Marques and colleagues present two abstracts of the 2-year primary outcome of the study at the EULAR congress.
The first abstract assesses the 2-year prevalence of an axSpA diagnosis among people with recent onset CBP who had been referred to a rheumatologist and investigates the sustainability of a baseline diagnosis ...
LAST 30 PRESS RELEASES:
Twelve questions to ask your doctor for better brain health in the new year
Microelectronics Science Research Centers to lead charge on next-generation designs and prototypes
Study identifies genetic cause for yellow nail syndrome
New drug to prevent migraine may start working right away
Good news for people with MS: COVID-19 infection not tied to worsening symptoms
Department of Energy announces $179 million for Microelectronics Science Research Centers
Human-related activities continue to threaten global climate and productivity
Public shows greater acceptance of RSV vaccine as vaccine hesitancy appears to have plateaued
Unraveling the power and influence of language
Gene editing tool reduces Alzheimer’s plaque precursor in mice
TNF inhibitors prevent complications in kids with Crohn's disease, recommended as first-line therapies
Twisted Edison: Bright, elliptically polarized incandescent light
Structural cell protein also directly regulates gene transcription
Breaking boundaries: Researchers isolate quantum coherence in classical light systems
Brain map clarifies neuronal connectivity behind motor function
Researchers find compromised indoor air in homes following Marshall Fire
Months after Colorado's Marshall Fire, residents of surviving homes reported health symptoms, poor air quality
Identification of chemical constituents and blood-absorbed components of Shenqi Fuzheng extract based on UPLC-triple-TOF/MS technology
'Glass fences' hinder Japanese female faculty in international research, study finds
Vector winds forecast by numerical weather prediction models still in need of optimization
New research identifies key cellular mechanism driving Alzheimer’s disease
Trends in buprenorphine dispensing among adolescents and young adults in the US
Emergency department physicians vary widely in their likelihood of hospitalizing a patient, even within the same facility
Firearm and motor vehicle pediatric deaths— intersections of age, sex, race, and ethnicity
Association of state cannabis legalization with cannabis use disorder and cannabis poisoning
Gestational hypertension, preeclampsia, and eclampsia and future neurological disorders
Adoption of “hospital-at-home” programs remains concentrated among larger, urban, not-for-profit and academic hospitals
Unlocking the mysteries of the human gut
High-quality nanodiamonds for bioimaging and quantum sensing applications
New clinical practice guideline on the process for diagnosing Alzheimer’s disease or a related form of cognitive impairment or dementia
[Press-News.org] Crossing the ring: new method enables C-H activation across saturated carbocyclesScripps Research chemists add another powerful tool to their “molecular editing” toolkit for crafting pharmaceuticals and other valuable compounds