Alkanes Research Articles

Cryogenic Organometallic Carbon-Fluoride Bond Functionalization with Broad Functional Group Tolerance.

The unique properties of fluorinated organic compounds have received intense interest and have conquered a myriad of applications in the chemical and pharmaceutical sciences. Today, an impressive range of alkyl fluorides are commercially available, and there are many practical methods to make them exist. However, the unmatched stability and inertness of the C-F bond have largely limited its synthetic value, which is very different from the widely accepted utility of alkyl chlorides, bromides, and iodides that serve everyday as "workhorse" building blocks in countless carbon-carbon bond forming reactions. This study demonstrates practical and high-yielding functionalization of the C-F bond under mild conditions, i.e., at temperatures as low as -78 °C, in short reaction times and with unconventional chemoselectivity. Cryogenic Csp3-F bond cleavage using fluorophilic organoaluminum compounds together with fast nucleophile transfer of intermediate ate complexes forge carbon-carbon bonds with unactivated primary, secondary, and tertiary alkyl fluorides alike. This method, which exploits the stability of the Al-F bond as the thermodynamic driving force, is highly selective toward Csp3-F bond functionalization, whereas many other functional groups including alkyl chloride, bromide, iodide, aryl halide, alkenyl, alkynyl, difluoroalkyl, trifluoromethyl, ether, ester, hydroxyl, acetal, heteroaryl, nitrile, nitro, and amide groups are tolerated, which is an unexpected reversal of long-standing main group organometallic and alkyl halide cross-coupling reactivity and compatibility patterns. As a result, the strongest single bond in organic chemistry can now be selectively targeted in high-yielding arylation, alkylation, alkenylation, and alkynylation reactions and used in late-stage functionalization applications that are complementary to currently available methods.

Metabolomic-Based Assessment of Earthworm (Eisenia fetida) Exposure to Different Petroleum Fractions in Soils

Background/Objectives: Petroleum contamination in soil exerts toxic effects on earthworms (Eisenia fetida) through non-polar narcotic mechanisms. However, the specific toxicities of individual petroleum components remain insufficiently understood. Methods: This study investigates the effects of four petroleum components—saturated hydrocarbons, aromatic hydrocarbons, resins, and asphaltenes—on earthworms in artificially contaminated soil, utilizing a combination of biochemical biomarker analysis and metabolomics to uncover the underlying molecular mechanisms. Results: The results revealed that aromatic hydrocarbons are the most toxic fraction, with EC50 concentrations significantly lower than those of other petroleum fractions. All tested fractions triggered notable metabolic disturbances and immune responses in earthworms after 7 days of exposure, as evidenced by significant changes in metabolite abundance within critical pathways such as arginine synthesis, a-linolenic acid metabolism, and the pentose phosphate pathway. According to the KEGG pathway analysis, saturated hydrocarbon fractions induced marked changes in glycerophospholipid metabolism, and arginine and proline metabolism pathways, contributing to the stabilization of the protein structure and membrane integrity. Aromatic hydrocarbon fractions disrupted the arachidonic acid metabolic pathway, leading to increased myotube production and enhanced immune defense mechanisms. The TCA cycle and riboflavin metabolic pathway were significantly altered during exposure to the colloidal fraction, affecting energy production and cellular respiration. The asphaltene fraction significantly impacted glycolysis, accelerating energy cycling to meet stress-induced increases in energy demands. Conclusions: Aromatic hydrocarbons accounted for the highest level of toxicity among the four components in petroleum-contaminated soils. However, the contributions of other fractions to overall toxicity should not be ignored, as each fraction uniquely affects key metabolic pathways and biological functions. These findings emphasize the importance of monitoring metabolic perturbations caused by petroleum components in non-target organisms such as earthworms. They also reveal the specificity of the toxic metabolic effects of different petroleum components on earthworms.

Development of a Highly Selective Synthesis of 4–Substituted Tetrahydroquinolines: Substrate Scope and Mechanistic Study

Herein, we describe a general and selective deprotonation functionalization reaction of tetrahydroquinolines at the 4–position using organolithiums and phosphoramide ligands. In addition to the development of a direct deprotonation alkylation reaction with primary and secondary alkyl halides, a Negishi cross–coupling protocol was realized to afford products with a range of aromatic halides. These methods were applied to the late‐stage installation of tetrahydroquinolines into a variety of substrates including pharmaceuticals as well as natural product analogues. The use of thorough mechanistic investigations revealed the aggregation state of the newly formed tetrahydroquinoline anion to be a separated ion pair, which proved critical to optimizing the reaction conditions.

Co-Catalytic Coupling of Alkyl Halides and Alkenes: the Curious Role of Lutidine.

Continuous pressure to shorten synthetic sequences along with the concomitant expansion of scope makes the use of alkyl bromides, chlorides, and oxygen based leaving groups- which are abundant and readily available feedstocks, highly attractive for C-C bond synthesis. However, selective activation of these bonds to generate radical intermediates remains challenging and is generally unfeasible using traditional activation strategies. Herein, we report a dual catalytic activation strategy to access primary, secondary, and tertiary alkyl radicals from respective alkyl chlorides and bromides, as well as primary tosylates and trifluoroacetates. While the method relies on visible light and a photocatalyst to facilitate electron transfer, based on reduction potentials, the substrates are not expected to be reduceable, and yet they are reduced in the presence of lutidine. Ultimately, our investigation revealed that lutidine was a precatalyst and ultimately led to the use of lutidinium iodide salt which served as a critical cocatalyst that resulted in improved reaction profiles. Our studies revealed two critical roles that lutidinium iodide salts play which made it possible to engage otherwise unreactive substrates: nucleophilic exchange and halogen atom transfer by the lutidinium radical. In short, this work converts unactivated alkyl chlorides, bromides, tosylates, and trifluoroacetates to radicals that can be used for C-C bond formation without the need for preactivation─effectively expediting synthesis.

Copper(I)-Photocatalyzed Addition of Trichloromethanesulfenyl Chloride to Olefinic Compounds

Atom transfer radical addition (ATRA) reactions are essential transformations in organic synthetic chemistry that enable the atom-economic difunctionalization of abundant olefin feedstocks. In this way, a rich chemical space can be opened up by well-planned combinations of simple starting materials. To build an efficient photocatalytic transformation, the reactivity of trichloromethanesulfenyl chloride toward alkenes and alkynes was investigated under photocatalytic Cu(I) reaction conditions. In this study, we found that trichloromethanesulfenyl chloride can be added to a series of olefins (such as styrenes and electron-rich and -poor olefins) in the presence of 1 mol% [Cu(dmp)2]BF4 photocatalyst and blue LED irradiation, producing α-chloro trichloromethylthioethers in good yields. Experimental and theoretical (DFT) mechanistic studies are consistent with the proposed radical chain mechanism of transformation. This study may serve as a valuable reference for the development of new coupling reactions that are economical and highly efficient processes.

Impact of gaseous smoke pollutants from modelled fires on air and soil quality

Forest fires produce large volumes of pollutants in the atmospheric air. Fires contribute significantly to greenhouse gas emissions worldwide apart from industrial and traffic pollutants. The study reports the results of research on the effect of gaseous substances from burning forest combustibles on air quality and deposition of emissions on soil. It was determined a significant excess in smoke of such substances as carbon monoxide (3570 mg/m3), nitrogen oxide and dioxide (40 mg/m3 and 60 mg/m3) saturated hydrocarbons – methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane nonadecane. The obtained results evidence the increased concentrations of pollutants, including climate-active substances in the air. They can affect negatively both the climate and ecological state of soils. A negative effect of gaseous products of combustion on soil (Haplic Chernozem) by deposition was determined, which caused changes in soil properties. It was reliably established that the enzymatic activity of soil (Haplic Chernozem) significantly decreased under the influence from smoke of fire during 60 min. Catalase appeared to be the most sensitive indicator. The catalase activity decreased by 25% compared to control values. Peroxidase activity decreased by 15%, urease by 20% and phosphatase by 16%. The pH changed from 7.8 to 6.3 after exposure of the soil to smoke. Soil microbiota was also adversely affected by smoke. High sensitivity was recorded for microscopic fungi. Their abundances decreased by 26%–87% after 10–60 min of smoke exposure. Bacteria were found to be more resistant to toxic smoke (28%–33% decrease in abundance). Therefore, smoke from fires can be considered as one of the factors that can affect soil.Graphical

Comprehensive effects of biochar-assisted nitrogen and phosphorus bioremediation on hydrocarbon removal and microecological improvement in petroleum-contaminated soil

Biochar is widely used in agricultural soils, but its effects with nitrogen and phosphorus amendments on petroleum-contaminated soil are unclear. This study investigated biochar-assisted biostimulation in a microcosm experiment, focusing on hydrocarbon degradation, nitrogen cycling, and soil properties. Compared to the biostimulation alone (BS), biochar combined biostimulation (BSC) significantly enhanced the abundances of petroleum hydrocarbon degraders including Lysobacter and Brevundimonas, which led to a 17% increase in total petroleum hydrocarbon (TPH) degradation, with 9% and 39% enhancements in saturated hydrocarbon degradation and aromatic hydrocarbon fraction degradation, respectively. Biochar also promoted ammonia and nitrous oxide oxidation by upregulating AOA, AOB, norB, and nosZ genes, while controlling nitrogen loss by downregulating nirK. Soil moisture, oxidation–reduction potential (ORP), dehydrogenase activity (SDHA), and microbial proliferation were significantly enhanced. Structural equation models (SEM) indicated synergistic interactions between nitrogen cycling and hydrocarbon degradation. Biochar enhances hydrocarbon degradation and nitrogen cycling, offering a promising soil remediation approach.

The Synergistic Inhibitory Effect and DFT Study of SAS60 and TAZ on Copper Chemical Mechanical Polishing

The chemical mechanical planarization (CMP) of multi-layer copper wires in giant-scale integrated circuits (GLSI) is one of the crucial processes for advancing microelectronic technology. The inhibitor is an important factor for achieving the planarization of copper wafers, and the addition of surfactant can improve the surface quality, so the combined use of inhibitor and surfactant has been a hot spot of research. In this study, the effect of sodium secondary alkyl sulfonate (SAS60) and 1,2,4-triazole (TAZ) on copper surface when used in combination is analyzed in depth through polishing experiments, electrochemical experiments, contact angle experiments and surface characterization tests. The mechanism of action of SAS60 and TAZ is discussed using density functional theory (DFT) method. The results of the study show that the synergistic use of SAS60 and TAZ can achieve good effects: reduce the polishing rate of copper, improve the wettability, reduce the surface defects, and reduce the surface roughness. Furthermore, it was shown that SAS60 is more readily adsorbed on the copper surface than TAZ, and when TAZ and SAS60 are used in combination, the adsorption layer is denser and more stable, which helps to elucidate the synergistic effect of surfactants and inhibitors at the microscopic level.

Atmospheric oxygen mediated oxidation coupling of primary and secondary alcohols: synthesis of pyrazolo[1,5-a]pyrimidines.

An atmospheric oxygen-mediated oxidative coupling of primary and secondary alcohols for the synthesis of nitrogen-containing heterocycles has been developed. This method utilizes atmospheric oxygen as the sole, environmentally friendly oxidant to convert a variety of alkyl and aromatic primary alcohols into aldehyde equivalents, avoiding over-oxidation to carboxylic acids. Notably, these mild oxidation conditions are compatible with both primary and secondary alkyl alcohols as substrates.

Circular Polymer Designed by Regulating Entropy: Spiro-Valerolactone-Based Polyesters with High Gas Barriers and Adhesion Strength.

Enthalpy is often the focal point when designing monomers for polymer circularity, but much less is explored on how entropy can be exploited to create polymers with synergistic circularity and properties. Here, we design a series of spiro-lactones (SLs) with closed-chain cycloalk(en)yl substituents at the α,α-position of δ-valerolactone (δVL), which, when combined with the parent δVL and gem-α,α-dialkyl-substituted δVL with open-chain alkyl groups, provide a desired platform for exploring the circular polymer design by focusing on the entropy change of polymerization. These SLs exhibit finely balanced (de)polymerizability that is regulated chiefly by entropy differentiation, allowing both the facile synthesis of polyester PSLs (Mn up to 1000 kg mol-1) in a living fashion and selective depolymerization of the PSLs to completely recover monomers under mild conditions (using a recyclable catalyst at 100 °C). One such PSL is semicrystalline (Tm = 134 °C), strong (ultimate strength = 43 MPa), hard (modulus = 1.85 GPa), and modestly flexible. These notable mechanical properties are bolstered by its superior barriers to oxygen and moisture permeation compared to common packaging materials. In addition, this PSL can be postfunctionalized to a recyclable OH-containing PSL that shows higher adhesion strength than the comparative commercial adhesives.

Intramolecular Fluoroacylation Enabled by TrBF4-Catalyzed Fluoride Recycling.

Alkyne- and alkene-tethered acyl fluorides undergo intramolecular carbofluorination via fluoride recycling using catalytic TrBF4. Excellent stereoselectivity is observed for the alkyne addition, enabling access to novel fluorinated indan-2-ones (all ≥95:5 E/Z) and cyclopentan-2-ones (85:15 E/Z). Fluorinated chroman-2-ones and tertiary alkyl fluorides can also be synthesized using this method, comparing favorably to previously reported protocols that employ expensive metal catalysts under harsher conditions.

A comparison of results of determining the hydrocarbon group-type composition of petroleum samples obtained using various test methods of open-column liquid chromatography

The hydrocarbon group-type composition (so-called SARA-composition) is one of the main characteristics of oil, providing an information about its chemical nature and determining the quality of the obtained petroleum products. In world laboratory practice, data on the hydrocarbon group-type composition of petroleum feedstock are widely used to assess its colloidal stability and compatibility with crude oil, reactivity in various conversion processes, predicting physical properties, etc. Traditionally, the hydrocarbon group-type composition is determined in accordance with standard and research chromatographic methods that differ significantly from each other, which often leads to obtaining incomparable analytical results. In this paper, a comparative analysis of the results of determining the hydrocarbon group-type composition obtained in accordance with two test methods within the open-column liquid chromatography method is carried out for various of petroleum samples of Russian origin (commercial oils of different classes and two petroleum products). Using the standard test method ASTM D4124 (method B) and the research test method developed by JSC VNII NP, the content of identical hydrocarbon groups in the maltene part of petroleum samples was determined: saturated hydrocarbons (SH) and paraffinic-naphthenic hydrocarbons (PNH), naphthenic aromatic (NAH) and aromatic hydrocarbons (AH), polar aromatic hydrocarbons (PAH) and resins (R), respectively. It is shown that with an increase the density and viscosity of petroleum samples, the content of less polar groups (SH and PNH) in their composition decreases and the content of more polar groups (PAH and R) obviously increases, and there is no pronounced distribution pattern of the NAH and AH groups. Statistical processing revealed insignificant differences in the results for «heavy and viscous» oils, despite the large error of those obtained according to the research test method. Obtaining comparable results justifies the use of both test methods not only for the analysis of high-boiling petroleum products, but also for the analysis «heavy and viscous» oil samples.

Innovative microbial activators for enhanced bioremediation of oil-contaminated soils: mechanistic insights.

This paper developed an efficient microbial activator formula and conducted an in-depth study on its efficacy and mechanism in promoting the degradation of petroleum hydrocarbons in oil-contaminated soil. A 60-day microbial remediation experiment conducted on oily soil revealed that the microbial activators significantly boosted the activities of dehydrogenase and catalase, subsequently speeding up the degradation of petroleum hydrocarbons in the soil. The overall degradation rate reached as high as 71.23%, with the most significant degradation effect observed in asphaltenes, achieving a degradation rate of 93.98%. This was followed by aromatic hydrocarbons (90.45%), saturated hydrocarbons (84.39%), and asphaltenes (65%). Compared to traditional microbial stimulation methods, this activator demonstrated significant superiority. Microbial diversity analysis reveals that microbial activators can effectively activate microbial activity in soil targeting refractory petroleum hydrocarbon components. By comparing the changes in microbial community structure before and after the addition of microbial activators, we found that the activators promoted an increase in the abundance of microorganisms belonging to the Bacillota, Pseudomonadota, and Bacteroidetes, which have petroleum hydrocarbon degradation functions, and facilitated the evolution of microbial community structure towards a direction more conducive to petroleum hydrocarbon degradation. KEGG metabolic pathway analysis revealed that the degradation pathways for alkanes, aromatic hydrocarbons, and PAHs are primarily present in these bacterial phylum. This research not only clarifies the degradation mechanism but also supports future bioremediation efforts.

Molecular Insights into the Control Mechanism of the Solid-Liquid Interface Interaction on Shale Oil Occurrence: Grand Canonical Monte Carlo and Molecular Dynamics Simulations Investigation.

The strong solid-liquid interaction leads to the complicated occurrence characteristics of shale oil. However, the solid-liquid interface interaction and its controls of the occurrence state of shale oil are poorly understood on the molecular scale. In this work, the adsorption behavior and occurrence state of shale oil in pores of organic/inorganic matter under reservoir conditions were investigated by using grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations. The adsorption potential energy and interaction energy were quantitatively evaluated, and the control mechanism of the oil-rock interaction on shale oil occurrence was explained. Results show that the density distribution of shale oil is not uniform under the confined space. Multiple layers of adsorption of n-octane occur in graphene pores. The number of adsorbed layers is mainly affected by pore size. With the increasing temperature and pore size, the adsorption site shifts from the high-energy to low-energy site and the solid-liquid interaction weakens. The effect of pressure on the occurrence state can be ignored due to capillary condensation. Minerals and oil chemical compositions also affect the oil-rock interaction and occurrence state. The adsorption intensity of minerals to n-octane decreases in the order graphene > montmorillonite > quartz. Competitive adsorption occurs among oil components. The adsorption order of oil components in graphene is asphaltenes > resin > nonhydrocarbon compound > aromatic hydrocarbons > saturated hydrocarbons. Asphaltenes preferentially adsorb on the surface of organic matter and occupy most of the adsorption surface, while saturated hydrocarbons mainly adsorb on the surface of heavy components or distribute in the pore center. The molecular structure of hydrocarbons also affects the adsorption characteristics. The long-chain hydrocarbons preferentially adsorb on the surface more than short-chain hydrocarbons. The straight-chain hydrocarbons preferentially adsorb more than the branched-chain hydrocarbons. This study provides the microscopic interaction between shale oil and minerals and explores the effect of the control mechanism of the oil-rock interfacial interaction on the occurrence state at the molecular level.

Secondary Alkylation of Arenes via the Borono-Catellani Strategy.

A modular platform technology for the synthesis of α-aryl carbonyl derivatives via Borono-Catellani-type secondary alkylation of arenes is presented. This practical method features a broad substrate scope regarding aryl boronic acid catechol esters, secondary alkyl bromides, and diversified terminating reagents (e.g., olefins, alkynes, and Zn(CN)2), mild reaction conditions, and good functional-group tolerance. Importantly, the asymmetric version based on a dynamic kinetic asymmetric transformation (DyKAT) has also been realized by introducing the 1:1 diastereomeric mixture of α-bromo carboxamides bearing an Evans chiral auxiliary as the electrophiles, and constantly excellent diastereoselectivities (>20:1 d.r.) are obtained. Notably, the obtained chiral products can be readily transformed into diversified enantioenriched α-aryl propionic acid derivatives, laying a solid foundation for the discovery of new NSAIDs. Through mechanistic studies and DFT calculations, a critical stereoretentive oxidative addition step is revealed in this Borono-Catellani secondary alkylation reaction, and the origins of stereodiscrimination of this DyKAT are well explained.

Altering the redox status of Chlamydia trachomatis directly impacts its developmental cycle progression.

Chlamydia trachomatis is an obligate intracellular bacterial pathogen with a unique developmental cycle. It differentiates between two functional and morphological forms: the elementary body (EB) and the reticulate body (RB). The signals that trigger differentiation from one form to the other are unknown. EBs and RBs have distinctive characteristics that distinguish them, including their size, infectivity, proteome, and transcriptome. Intriguingly, they also differ in their overall redox status as EBs are oxidized and RBs are reduced. We hypothesize that alterations in redox may serve as a trigger for secondary differentiation. To test this, we examined the function of the primary antioxidant enzyme alkyl hydroperoxide reductase subunit C (AhpC), a well-known member of the peroxiredoxins family, in chlamydial growth and development. Based on our hypothesis, we predicted that altering the expression of ahpC would modulate chlamydial redox status and trigger earlier or delayed secondary differentiation. Therefore, we created ahpC overexpression and knockdown strains. During ahpC knockdown, ROS levels were elevated, and the bacteria were sensitive to a broad set of peroxide stresses. Interestingly, we observed increased expression of EB-associated genes and concurrent higher production of EBs at an earlier time in the developmental cycle, indicating earlier secondary differentiation occurs under elevated oxidation conditions. In contrast, overexpression of AhpC created a resistant phenotype against oxidizing agents and delayed secondary differentiation. Together, these results indicate that redox potential is a critical factor in developmental cycle progression. For the first time, our study provides a mechanism of chlamydial secondary differentiation dependent on redox status.

Functionalization of Pyridines at the C4 Position via Metalation and Capture.

The functionalization of pyridines at positions remote to the N-atom remains an outstanding problem in organic synthesis. The inherent challenges associated with overriding the influence of the embedded N-atom within pyridines was overcome using n-butylsodium, which provided an avenue to deprotonate and functionalize the C4-position over traditionally observed addition products that are formed with organolithium bases. In this work, we show that freshly generated 4-sodiopyrdines could undergo transition metal free alkylation reactions directly with a variety of primary alkyl halides bearing diverse functional groups. In addition, after transmetalation to zinc chloride a simple and efficient Negishi cross-coupling protocol was formulated for a variety of aromatic and heteroaromatic halides. The robustness of this protocol was demonstrated through the late-stage installation of 4-pyridyl fragments into a variety of complex active pharmaceutical ingredients including loratadine and prochlorperazine. Furthermore, through rapid injection NMR investigations, we are able to directly observe the evolution of anionic intermediates and determined that two distinct mechanistic pathways lead to the observed site selectivity: (1) the C4-H within 2,6-disubstituted pyridines could be removed directly and (2) the C4 selectivity of unsubstituted pyridine originates from the intermolecular exchange of metalation sites via a thermodynamic pathway.

Synthesis of Enantioenriched 2‐((Hetera)Cyclo) Alkylchromanols and their Spirocyclic Analogs through Enzymatic Resolution

AbstractAn efficient approach to the multigram synthesis of 2‐((hetera) cyclo) alkylchromanols and their spirocyclic analogs based on enzymatic resolution is described. It is shown that enzymatic acylation could be used for the preparation of enantioenriched title compounds with primary alkyl substituents at the C‐2 position. Meanwhile, enzymatic hydrolysis of the corresponding acetates was optimal for the preparation of the target alcohols when significant steric hindrance is present, e. g., due to the α‐branching. The latter factor was demonstrated to be crucial for the enzymatic reaction rate in both cases. The synthetic utility of the obtained chiral alcohols was demonstrated through Mitsunobu configuration inversion, as well as by preparation of the corresponding primary amines – valuable sp3‐enriched building blocks for medicinal chemistry.

Ni-Catalyzed Enantioselective Desymmetrization: Development of Divergent Acyl and Decarbonylative Cross-Coupling Reactions.

Ni-catalyzed asymmetric reductive cross-coupling reactions provide rapid and modular access to enantioenriched building blocks from simple electrophile precursors. Reductive coupling reactions that can diverge through a common organometallic intermediate to two distinct families of enantioenriched products are particularly versatile but underdeveloped. Here, we describe the development of a bis(oxazoline) ligand that enables the desymmetrization of meso-anhydrides. When secondary benzylic electrophiles are employed, doubly stereoselective acyl cross-coupling proceeds to give ketone products with catalyst control over three newly formed stereogenic centers. Alternatively, the use of primary alkyl halides in the presence of an additional halogen atom transfer catalyst results in decarbonylative alkylation to give enantioenriched β-alkyl acids. Analysis of reaction rates for a range of both catalysts and substrates supports the notion that tuning the different electrophile activation steps with the two catalysts is required for enhanced reaction performance. These studies illustrate how reaction design can diverge a common Ni-acyl intermediate to either acyl or decarbonylative coupling products and highlight how dual ligand systems can be used to engage unactivated alkyl halides in Ni-catalyzed asymmetric reductive coupling.

Tracking hydrothermal infiltration within light oil reservoirs using organic geochemical proxies in the Shunbei area of Tarim Basin in China

Deep oil reservoirs are becoming increasingly significant fields of hydrocarbon exploration in recent decades. Hydrothermal fluid flow is deemed as a potentially crucial factor affecting the occurrence of deep oil reservoirs, such as enhancing porosity/permeability of reservoirs, accelerating oil generation and thermal cracking, and modifying organic properties of crude oils. Understanding the interplay between hydrothermal fluids and crude oils would provide useful constraints for reconstructing hydrocarbon accumulation processes and predicting the distribution patterns of crude oils. Voluminous crude oils have been discovered in the deeply buried Ordovician carbonate reservoirs within the Shunbei area of the northern Tarim Basin. Previous studies revealed that the Early Permian Tarim Large Igneous Province (LIP) has affected the Shunbei area, whereas it is still debated whether the LIP-related hydrothermal infiltration affected hydrocarbons within the Ordovician reservoirs. To resolve this puzzle, this study was designed to unravel the potential thermal impact of hydrothermal infiltration on hydrocarbons according to molecular and stable carbon isotopic compositions of oils and associated natural gases, reflectance analysis of solid bitumen, and fluid inclusion thermometry. The studied crude oils are characterized by uniform organic indicators of paraffin, terpanes, steranes, and light hydrocarbons, implying that crude oils are derived from the same source rock. Genetic binary diagrams, such as dibenzothiophene/phenanthrene (DBT/P) vs. Pr/Ph (pristane/phytane), Pr/n-C17 alkane vs. Ph/n-C18 alkane, C31R/C30hopane vs. C26/C25tricyclic terpane (TT), and C24/C23 TT vs. C22/C21 TT, indicate that marine shales deposited in a reducing-weakly oxidized environment are major source rocks. Natural gases are associated with oil reservoirs and are mainly generated via the decomposition of kerogen and crude oil. Solid bitumen with abnormally high reflectance values (2.17–2.20%) occurred in the studied area, suggesting their formation temperatures were 252–254 °C. The abnormally high temperatures may be caused by hydrothermal infiltration related to the Tarim LIP. Hydrothermal infiltration is supported by the presence of high contents of CO2 (30–48%) with enriched δ13C ratios (between − 2.5‰ and − 2.3‰), enriched n-alkane δ13C ratios, and incongruent temperatures estimated by multiple indicators, such as light hydrocarbon compositions, homogenization temperatures of fluid inclusions, and bitumen reflectance. Outcomes of this study support the interpretation that hydrothermal infiltration indeed occurred and may have facilitated hydrocarbon generation in the Shunbei area, and possibly elsewhere in the cratonic regions of the northern Tarim Basin.