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A formal [3 + 2] annulation reaction of crotonate-derived sulfur ylides and β-ketothioamides (KTAs) was successfully developed to produce good-to-excellent yields of thiazoline and spiro[indoline-3,3′-thiophene] scaffolds.

The direct conversion of glyceric acid to succinic acid by reductive carbonylation is reported for the first time.

3-iodopropionic acid (3-IPA) can be efficiently synthesized from the glycerol derivative glyceric acid (GA), which is a potential biomaterial-based platform molecule. In this report, ethyl 3-iodopropionate was rapidly dimerized to diethyl adipate in a microwave reactor using NiCl2·6H2O as a catalyst, co-catalyzed by Mn and the 1, 10-Phenanthroline monohydrate ligand. Under the optimum reaction conditions, diethyl adipate can be obtained with 84% yield at 90 °C in just 5 min. Diethyl adipate was hydrolyzed to obtain the adipic acid (AA) in 89% yield with an acid catalyst. AA is an important chemical and a monomer for producing a wide range of high-performance polymeric substances. This rapid coupling method is also applicable to other alkyl halides.

The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.

Norpimarane diterpenes possess plentiful bioactivities and are widely distributed in herbs, such as Flickingeria fimbriata. Rapid characterization of these natural products in complicated plant extracts is of great importance, and electrospray ionization tandem mass spectrometry is a powerful tool for chemical constituent profiling. However, limited researches on their fragmentation mechanisms seriously hinder identification via mass spectrometry.Three norpimarane diterpenes isolated from F. fimbriata via multiple types of column chromatography served as reference compounds, and collision-induced dissociation experiments were performed on them with a series of variable collision energies. Plausible fragmentation pathways were proposed based on product ions. To further validate the fragmentation mechanisms, the proton affinity and product ion energy were simulated by density functional theory at the B3LYP/6-31+G(d, p) level.Three main cleavage reactions induced skeleton breakage and resulted in characteristic ions, methyl (CHFragmentation mechanisms of norpimarane diterpenes have been uncovered. Carbocation located at the C ring tends to result in methyl (CH

Methyl levulinate (ML) is a biobased platform molecule, which has versatile applications in fine chemical synthesis and food additives. However, during the ML production, one of the main barriers i...

An unparalleled [4 + 2]-annulation of prop-2-ynylsulfonium salts with isatoic anhydrides was developed, affording a series of 4-quinolones with a alkylthio group in medium to good yields under mild conditions. In this reaction type, the prop-2-ynylsulfonium salt serves as a C2 synthon and sulfide does not act as a leaving group, providing facile access to organosulfur compounds. The resulting quinolone products could be further transformed to a diverse range of synthetically useful compounds.

As a bio-based platform chemical, it is desirable to convert levulinic acid (LA) to varieties of value-added biochemicals. n-Butane, mainly from nonrenewable fossil resources, is a basic chemical to produce some important chemicals, such as butadiene and ethylene. In this paper, 95.5% yield of n-butane was obtained from LA in one-step over base-treated Pt/C at around 300 °C in 4 h. The reaction pathway was confirmed to be the hydrodeoxygenation of LA to valeric acid (VA) and then the VA decarboxylation to n-butane by kinetic studies. Base-treated Pt/C had better reactivity due to its improved decarboxylation activity. Detailed characterization of the catalyst revealed that the Pt particle size is the key reason for the activity improvement, and further studies showed that Pt nanoparticles with a size of 2–4 nm showed the highest decarboxylation activity. This is the first report on the direct conversion of LA to n-butane.

As an important biomass-derived chemical, d-sorbitol can be converted to a variety of useful chemicals and fuels. Because of the strong nucleophilicity of I– and reducibility of hydrogen iodide (HI...

A sequential [3 + 2] annulation of prop-2-ynylsulfonium salt and N-ylides was developed, leading to the formation of a series of pyrrolo[2,1-a]quinolines, pyrrolo[2,1-a]phthalazines and indolizines. The protocol featured the simultaneous one-pot formation of three new C-C bonds in moderate yields under mild conditions. In this reaction, the prop-2-ynylsulfonium salts acted as the C2 synthons and sulfide served as the leaving group. The resultant products could serve as useful precursors for the synthesis of diverse chemical compounds.

For the first time, the [4 + 3] or [2 + 1] annulation of crotonate-derived sulfur ylides with arylidenemalononitrile or arylidene-1H-indene-1,3(2H)-dione is reported using Na2CO3 as the base. This protocol is advantageous as it does not require prior preparation of arylidenemalononitrile or arylidene-1H-indene-1,3(2H)-dione substrates, due to the independent participation of the base in the two reactions. This mild, operationally multicomponent process can be employed for the transformation of a wide variety of commercially available aldehydes into the corresponding indeno[1,2-b]oxepine or cyclopropyl acrylate core in moderate to excellent yields under mild conditions.

Propionic acid (PA), a valuable chemical widely used in the food and feed industry, is currently produced by the petrochemical industry. Selective production of PA from bio-based lactic acid (LA) is difficult due to the high activation energy of the hydroxyl group at the α position of the carboxyl group. Herein, a metal-free catalytic system for the highly selective transformation of bio-based LA to PA, which was used as the solvent to simplify the separation step, is reported using NaI as the catalyst. Under the optimal reaction conditions, a >99% yield of PA can be obtained from LA. A heat-induced radical-activated hydrogen mechanism was proposed based on the kinetic study and intermediate capture. The metal-free system can be reused five times without any loss in activity, and the PA product is easily separated. In addition, a two-step method using cellulose as the raw material to produce PA was conducted. This strategy offers a green and efficient approach to synthesize PA from biomass resources.

Currently, low intimacy between hydrogenation sites and acidic sites causes unsatisfactory catalytic activity and selectivity for the synthesis of 2,5-hexanedione from C

Herein, a robust catalytic system was developed for the green synthesis of 5-methylfurfural (5-MF) by iodide-mediated transfer hydrogenation. Around 50 % of 5-MF was yielded from d-fructose within 7.5 min using NaI as the catalyst and formic acid as both the hydrogen source and co-catalyst. The catalytic system was used for six consecutive cycles without any decrease in the yield. Various starch and raw biomass could be used as promising starting materials for 5-MF synthesis with moderate yields, and the productivity of 5-MF from corn starch reached 103 mmol gcat-1 h-1 , which is comparable with the best result from l-rhamnose. Moreover, the co-production of 5-MF and furfural from raw biomass makes this methodology more competitive than other routes.

Former study suggests alkaloids from herbs of Aconitum genus plants possess excellent bioactivities, which exert great value for related deeper chemical constituent investigation. Herein, chemical isolation was performed and four alkaloids were isolated from Fuzi, of which two were new ones, and the other two were reported NMR data for the first time. Their chemical structures were identified by NMR data, high resolution MS, UV and IR analysis. Additionally, the MS fragmentation patterns were explored, formerly, that of hetisane alkaloid was rarely reported, and fragmentation mechanism of the diagnostic ion was proposed. Based on these fragment pathway, metabolites and metabolic pathways of four compounds were investigated in rat liver microsomes using UPLC-Q/TOF-MS, and dehydrogenation product was firstly found from metabolites of hetisane alkaloid.

To investigate the effects of continuous monitoring intracranial pressure (ICP) and brain oxygen partial pressure (PbtOA prospective randomized controlled trial was conducted. Seventy patients with severe craniocerebral injury with a Glasgow coma score (GCS) 4-8 admitted to the neurosurgical intensive care unit (NICU) of the People's Hospital of Inner Mongolia Autonomous Region from January 2017 to May 2020 were enrolled, and they were divided into ICP monitoring group and ICP+PbtOFinally, a total of 70 patients with severe craniocerebral injury were enrolled in the analysis, 34 patients received ICP combined with PbtOPbtO

In this study, an unprecedented [4 + 3] annulation of aza-ortho-quinone methides with azomethine imines was achieved under mild conditions. Annulation via the aza-Michael/aminalization sequence served as a useful method to synthesize biological heterocycles in good-to-excellent yields.

The waste rice straw is a sustainable bioresource with large reserves and low-cost, thus can be used to produce fuels and chemicals to enhance its value. In this paper, we have developed a new method to convert rice straw into biogasoline with high yield in one step by using multifunctional catalyst of RhCl3/NaI/HCl/H2 in a biphasic reaction system. Lipid and lignin in the rice straw hindered its conversion and need to be removed by pretreatment. The major products are C5 and C6 furan, furfural, and cyclic ketones, which are low in oxygen content and can be used as biogasoline. Under the optimal reaction conditions (140 °C, 4 h, 300 psi H2, toluene to water volume ration 1:1), C5 from hemicellulose with 77.2% yield and C6 from cellulose with 71.7% yield can be obtained. The total biogasoline yield based on dry rice straw is 23.5 wt%, which is quite significant. The mechanism of the conversion process was also well studied.

Glycerol, generated in abundance as the by-product in the process of biodiesel production and saponification, has seen attempts to convert it into value-added chemicals. However, due to the low selectivity of hydrogenolysis of the secondary hydroxyl group, valuable 1,3-substituted chemicals are difficult to obtain from glycerol by chemocatalysis. In this work, glyceric acid (GA), a renewable biomass from glycerol, was quantitatively converted to 3-iodopropionic acid (3-IPA) at 373 K in 3 h by hydroiodic acid mediated hydrogenation. As the reductant in this process, HI is oxidized to I2 and then regenerated in situ by metal catalysts and H2. The reaction pathway was proposed by intermediate identification and verified by a kinetics study and computational method. The catalytic system was shown to be stable and can be reused several times without loss in activity. As a 1,3-substituted chemical, 3-IPA is not only a potential monomer to form poly-3-hydroxypropionic acid, but also a good platform molecule to produce useful chemicals, e.g. 3-hydroxypropionic acid (3-HPA) and acrylic acid (AA), due to its highly reactive nature.

Production of biodiesel from biomass resources usually requires elongation of carbon numbers from typical C5 and C6 platform molecules through C–C coupling reactions, which were catalyzed by acid, base or metal catalysts traditionally. Herein, a catalyst-free method was developed to produce bis(furan-2-yl)methane derivatives (BFMs) from furfuryl alcohol derivatives (FAs) in the presence of H2O and air without any other additional catalysts. An 81% yield of bis(5-methylfuran-2-yl)methane (BMFM) can be obtained from 5-methylfurfuryl alcohol (5-MFA) and a 59% total yield of C11 biodiesel was obtained from 5-methylfurfural (5-MF). In addition, a H2O and air mediated free radical decarboxylation mechanism was proposed based on the detailed mechanistic studies. This strategy offers a green, low-cost and environmentally friendly approach to synthesize biodiesel precursors from biomass based platform molecules.

Aconitum alkaloids are versatile in chemical structures and are well known for their bioactivity and toxicity. Cases of analogs with closely similar structures or positional isomers are widespread in herbs of the Aconitum genus. It is still challenging to rapidly identify unknown compounds via mass spectrometry, especially positional isomers. Herein, to profile the alkaloids of Aconitum stapfianum that possess bioactivity against intoxication by the lateral root of Aconitum carmichaelii (Fuzi), a strategy was developed by carefully determining the fragmentation pathways of authentic standards. A series of rules was summarized and involved charge site effects, hydrogen bonding effects, competitive channels between charge-remote reactions and charge migration reactions, and fragment patterns exhibiting a "diamond shape". Accordingly, a total of 124 alkaloids in A. stapfianum were tentatively characterized, including 85 potential new compounds and 24 sets of isomers. On the other hand, to explore the material basis of detoxification, a chemical constituent comparison was made between A. stapfianum and Fuzi, and principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were performed to identify markers that were different between the two . In total, 25 characteristic markers were identified to discriminate between these two herbal medicines, of which 14 compounds were specific for A. stapfianum and most of them were characteristic for a para-substituted benzoic acid ester at C-14.

Catalytic transfer hydrogenation is gaining increasing attention as a promising alternative to conventional hydrogenation with H2. In present work, a series of modified Zr-based catalysts were synthesized and tested for furfural catalytic transfer hydrogenation into furfuryl alcohol (FA). The results indicated that more than 13 % of furfural conversion and furfuryl alcohol yield could be achieved with modified zirconium hydroxide (mZrH) at 140 °C when compared with zirconium hydroxide (ZrH) using ethanol as H-donor and solvent in continuous flow regime, and the activity could be further enhanced by increasing the reaction temperature or Ru loading on the catalyst. The best result of 92 % furfural conversion with ∼99 % FA selectivity was obtained at 150 °C with 6% Ru/mZrH as catalyst, and the productivity of FA is 5.5 mmol g−1 h−1 which is 2 times higher than that reported with ZrH in batch. Moreover, long-term stability study of the catalysts indicated that 6% Ru/mZrH not only performs a better activity, but also a better stability than 6% Ru/ZrH. Characterizations of the catalysts by BET, XRD, EA, IR, SEM-EDS, XPS and CO2 adsorption indicated that zirconium hydroxide (ZrH) was successfully modified with hydroxylamine, leading to significantly change of its morphology and basic sites. And the deactivation of the catalysts was due to both the leaching of Ru and the deposition of side-products on its surface.

A sequential [3 + 2]/[2 + 1] annulation domino reaction of crotonate-derived sulfur ylides and Morita-Baylis-Hillman carbonates of isatins for the construction of oxospiro[bicyclo[3.1.0]hexane-6,3'-indolin] scaffolds in moderate to good yields with almost 1:1 diastereoselectivity has been developed. Mild reaction conditions and readily accessible starting materials as well as excellent functional group compatibility render this transformation a powerful tool for the synthesis of spirocyclopropyloxindoles. A gram-scale synthetic procedure was also successfully carried out and a plausible reaction mechanism could be proposed.

As-enriched Pteris vittata L. (PVL, a kind of hyper-accumulator biomass) was converted into high-quality biofuel by the catalytic hydrogenolysis, aiming to achieve effective treatment and high-value utilization of hyper-accumulators. After pretreatment of PVL to remove lipids and lignin, more than 64% of heavy metals were transferred into water, and the As content in the solid biomass was reduced from 1328 mg/kg to 483 mg/kg. The multifunctional catalysts RhCl3/NaI/HCl/H2 were used in a biphasic reaction system to convert PVL into biofuel with high selectivity. The main products are C5 and C6 furans and low oxygen content ketones, which have a high heating value (HHV) and can be directly used as biofuel. The highest yields of C5 and C6 products were obtained with 60.2% and 61.1% (based on the corresponding hemicellulose and cellulose) under the optimal reaction conditions (160 °C, 4 h, 300 psi H2, 4 mmol NaI, H2O/toluene = 1:1). The total biofuel yield based on dry PVL was 18.8 wt.%. After the reaction, more than 50% heavy metals (Cu, Pb, Zn, Cd, As) remained in the bio-char, while the heavy metals in the biofuel were less than 20% (As content was less than 55 mg/kg). Therefore, catalytic hydrogenolysis was perceived as a promising technique for PVL treatment to obtain high-quality biofuel and arsenic recovery.