Synthesis of 2-(Trifluoromethyl)-[1,2,4]triazolo[5,1-a]isoquinoline via Cycloaddition of C,N-Cyclic Azomethine Imine with CF3CN.

A [3 + 2] cycloaddition of C,N-cyclic azomethine imine with in situ-generated CF3CN for the construction of 2-(trifluoromethyl)-[1,2,4]triazolo[5,1-a]isoquinoline is reported. Remarkably, this process shows a broad substrate scope with excellent functional group tolerance, which is scalable and enables a practical route to a library of 2-(trifluoromethyl)-[1,2,4]triazolo[5,1-a]isoquinoline derivatives in moderate to good yields.

The global mismatch between equitable carbon dioxide removal liability and capacity.

Limiting climate change to 1.5°C and achieving net-zero emissions would entail substantial carbon dioxide removal (CDR) from the atmosphere by the mid-century, but how much CDR is needed at country level over time is unclear. The purpose of this paper is to provide a detailed description of when and how much CDR is required at country level in order to achieve 1.5°C and how much CDR countries can carry out domestically. We allocate global CDR pathways among 170 countries according to 6 equity principles and assess these allocations with respect to countries' biophysical and geophysical capacity to deploy CDR. Allocating global CDR to countries based on these principles suggests that CDR will, on average, represent ∼4% of nations' total emissions in 2030, rising to ∼17% in 2040. Moreover, equitable allocations of CDR, in many cases, exceed implied land and carbon storage capacities. We estimate ∼15% of countries (25) would have insufficient land to contribute an equitable share of global CDR, and ∼40% of countries (71) would have insufficient geological storage capacity. Unless more diverse CDR technologies are developed, the mismatch between CDR liabilities and land-based CDR capacities will lead to global demand for six GtCO2 carbon credits from 2020 to 2050. This demonstrates an imperative demand for international carbon trading of CDR.

Synthesis of 2-trifluoromethyl benzimidazoles, benzoxazoles, and benzothiazoles via condensation of diamines or amino(thio)phenols with CF3CN.

A new and efficient method is developed for the synthesis of 2-trifluoromethyl benzimidazoles, benzoxazoles, and benzothiazoles in good to excellent yields by the condensation of diamines or amino(thio)phenols with in situ generated CF3CN. Additionally, the synthetic utility of the 2-trifluoromethyl benzimidazole and benzoxazole products is demonstrated via gram scale synthesis. The mechanistic study suggests that the reaction proceeds via the nucleophilic addition of trifluoroacetonitrile to the amino group of the diamine derivatives to form an imidamide intermediate, followed by intramolecular cyclization.

Core-shell-structured Mn2SnO4@Void@C as a stable anode material for lithium-ion batteries with long cycle life.

Owing to its high theoretical specific capacity, Mn2SnO4 has been regarded as a promising electrode material for lithium-ion batteries. However, in suffering from huge volume expansion and pulverization amidst the alloying/dealloying processes, it presents difficulties in applications as an anode material. Herein, a core-shell-structured Mn2SnO4@Void@C anode material was successfully synthesized using a layer-wise assembly and selective etching method. Tetraethyl silicate (TEOS) and resorcinol formaldehyde resin, serving, respectively, as sacrificial template (SiO2) and carbon layer sources, were coated successively onto Mn2SnO4 particles. Adopting an alkali etching process, the SiO2 template was removed, and a Mn2SnO4@Void@C was therewith constructed. As Mn2SnO4 is well wrapped by a carbon shell and there are enough voids therein, its volume expansion whilst cycling can be significantly buffered. Moreover, the porous structure in Mn2SnO4@Void@C can provide convenient channels for ion transport and alleviate volume changes. Mn2SnO4@Void@C exhibits upgraded capacity and long cycling stability, since its specific capacity is maintained at 783.1 mA h g-1 at 100 mA g-1 after 150 cycles and at 553.3 mA h g-1 at 1000 mA g-1 after 1000 cycles.

Regioselective synthesis of 3-trifluoromethyl 1,2,4-triazoles via photocycloaddition of sydnone with CF3CN.

A general and regioselective synthesis of 3-trifluoromethyl 1,2,4-triazoles has been achieved through photocycloaddition of sydnone with trifluoroacetonitrile. This method employed trifluoroacetaldehyde O-(aryl)oxime as the CF3CN precursor and tolerated various functional groups to furnish 3-trifluoromethyl 1,2,4-triazole products in moderate to good yields. Mechanistic experiments revealed an energy transfer from photocatalyst 4-CzIPN to the sydnone substrates.

Regioselective Synthesis of 5-Trifluoromethyl 1,2,4-Triazoles via [3 + 2]-Cycloaddition of Nitrile Imines with CF3CN.

We herein describe a general approach to 5-trifluoromethyl 1,2,4-triazoles via the [3 + 2]-cycloaddition of nitrile imines generated in situ from hydrazonyl chloride with CF3CN, utilizing 2,2,2-trifluoroacetaldehyde O-(aryl)oxime as the precursor of trifluoroacetonitrile. Various functional groups, including alkyl-substituted hydrazonyl chloride, were tolerated during cycloaddition. Furthermore, the gram-scale synthesis and common downstream transformations proved the potential synthetic relevance of this developed methodology.

Synthesis of 2-trifluoromethyl thiazoles via [3 + 2] cycloaddition of pyridinium 1,4-zwitterionic thiolates with CF3CN.

2,2,2-Trifluoroacetaldehyde O-(aryl)oxime was employed for the [3 + 2] cycloaddition of pyridinium 1,4-zwitterionic thiolates for the synthesis of 2-trifluoromethyl 4,5-disubstituted thiazoles. The reaction works well with various substituted pyridinium 1,4-zwitterionic thiolates in moderate to good yields. The synthetic potential of the obtained 2-trifluoromethyl 4,5-disubstituted thiazoles was demonstrated.

An Economy-wide Analysis of the Energy and Environmental Impacts of International Trade Policy Adjustments for Chemical Industry in China.

In China, the proportion of energy consumption and carbon emissions embodied in international trade in chemical industry is high. It is important to consider how international trade policy adjustments in chemical industry will affect the economy and environment so as to achieve the goal of carbon intensity. This study investigates the impact of international trade policy adjustments. We adopt a computable general equilibrium model to simulate the impacts of trade policy adjustment. The result shows all adjustment plans cause economic losses. All plans will promote energy structure toward cleaner. All plans reduce CO2 emissions and energy consumption but cannot realize the carbon intensity and energy intensity target. The adjustment of tariff policy in basic raw materials sector should be smaller than that of other sectors. Raising the export tariff is the best policy choice for achieving the carbon intensity target, but other low-carbon policies should be introduced. In particular, protection measures should be taken for the energy industry.

2,2,2-Trifluoroacetaldehyde O-(Aryl)oxime: A Precursor of Trifluoroacetonitrile.

The preparation of 2,2,2-trifluoroacetaldehyde O-(aryl)oxime, a previously inaccessible precursor of trifluoroacetonitrile, via reaction of hydroxylamine and trifluoroacetaldehyde hydrate is reported. This precursor released CF3CN in quantitative yield under mildly basic conditions. The precursor was successfully used in the synthesis of trifluoromethylated oxadiazoles. The facile, cost-effective, scalable, and recyclable procedure makes these trifluoroacetonitrile precursors generally applicable.

An aerobic copper-mediated domino process for the synthesis of 3-(trifluoromethylseleno)indoles.

An aerobic copper-mediated domino reaction for the synthesis of 3-(trifluoromethylseleno)indoles by trifluoromethylselenolation of N-Ts 2-alkynylaniline with [(bpy)CuSeCF3]2 is reported. This reaction proceeds through sequential oxidation, alkyne coordination, and deprotonation followed by reductive elimination. This mild and robust method is highly functional group tolerant and provides straightforward access to 3-(trifluoromethylseleno)indoles in moderate to good yields.

Synthesis of 2,3-Bis(trifluoromethylseleno) Indoles through an Oxidative Copper-Mediated Domino Reaction.

An oxidative copper-mediated double trifluoromethylselenolation of terminal 2-alkynylanilines using [(bpy)CuSeCF3]2 is reported, providing a moderately efficient and convenient approach to 2,3-bis(trifluoromethylseleno)indoles. Mechanistic studies show that a cascade sequence of oxidation, trifluoromethylselenolation, 5-endo-dig cyclization, and elimination is involved in this transformation.