The transition metal catalyzed amide bond forming reaction of esters with amines has been developed as an advanced approach for overcoming the shortcomings of traditional methods. The broad scope of substrates in transition metal catalyzed amidations remains a challenge. Here, a manganese­(I)-catalyzed method for the direct synthesis of amides from a various number of esters and amines is reported with unprecedented substrate scope using a low catalyst loading. A wide range of aromatic, aliphatic, and heterocyclic esters, even in fatty acid esters, reacted with a diverse range of primary aryl amines, primary alkyl amines, and secondary alkyl amines to form amides. It is noteworthy that this approach provides the first example of the transition metal catalyzed amide bond forming reaction from fatty acid esters and amines. The acid–base mechanism for the manganese­(I)-catalyzed direct amidation of esters with amines was elucidated by DFT calculations.

An operationally simple method to employ non-activated carboxylic acids as alkylating agents in N-alkylation of heterocycles is reported through an electrochemically driven anodic decarboxylative process. A wide substrate scope across a range of heterocycles is demonstrated along with a series of applications that significantly reduce the step-count required to access such medicinally relevant structures.

BackgroundLignocellulosic biomass is one of earth’s most abundant resources, and it has great potential for biofuel production because it is renewable and has carbon-neutral characteristics. Lignocellulose is mainly composed of carbohydrate polymers (cellulose and hemicellulose), which contain approximately 75 % fermentable sugars for biofuel fermentation. However, saccharification by cellulases is always the main bottleneck for commercialization. Compared with the enzyme systems of fungi, bacteria have evolved distinct systems to directly degrade lignocellulose. However, most reported bacterial saccharification is not efficient enough without help from additional β-glucosidases. Thus, to enhance the economic feasibility of using lignocellulosic biomass for biofuel production, it will be extremely important to develop a novel bacterial saccharification system that does not require the addition of β-glucosidases.ResultsIn this study, a new thermophilic bacterium named Ruminiclostridium thermocellum M3, which could directly saccharify lignocellulosic biomass, was isolated from horse manure. The results showed that R. thermocellum M3 can grow at 60 °C on a variety of carbon polymers, including microcrystalline cellulose, filter paper, and xylan. Upon utilization of these substrates, R. thermocellum M3 achieved an oligosaccharide yield of 481.5 ± 16.0 mg/g Avicel, and a cellular β-glucosidase activity of up to 0.38 U/mL, which is accompanied by a high proportion (approximately 97 %) of glucose during the saccharification. R. thermocellum M3 also showed potential in degrading natural lignocellulosic biomass, without additional pretreatment, to oligosaccharides, and the oligosaccharide yields using poplar sawdust, corn cobs, rice straw, and cornstalks were 52.7 ± 2.77, 77.8 ± 5.9, 89.4 ± 9.3, and 107.8 ± 5.88 mg/g, respectively.ConclusionsThe newly isolated strain R. thermocellum M3 degraded lignocellulose and accumulated oligosaccharides. R. thermocellum M3 saccharified lignocellulosic feedstock without the need to add β-glucosidases or control the pH, and the high proportion of glucose production distinguishes it from all other known monocultures of cellulolytic bacteria. R. thermocellum M3 is a potential candidate for lignocellulose saccharification, and it is a valuable choice for the refinement of bioproducts.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0585-z) contains supplementary material, which is available to authorized users.

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The comparison of hydrogen production by conventional process and consolidated bioprocessing.

We report a new approach to synthesize palladium complexes through Ag2O-promoted hydrolytic ring opening followed by palladium coordination. The novelty of Ag2O-promoted hydrolysis in comparison with the commonly used base-mediated hydrolysis lies in the anion-controlled product selectivity in the synthesis of pincer-type palladium complexes. Moreover, these palladium complexes have been tested in the Suzuki reaction using aryl bromides in methanol and H2O, respectively. In comparison with palladium complexes with normal coordination, the palladium complexes generated from the hydrolytic ring-opening coordination demonstrate excellent catalytic activity.

In this paper, we propose a new rate allocation algorithm for transform domain Wyner-Ziv video coding (WZVC) without feedback. In contrast to conventional video coding, Wyner-Ziv video coding aims to design simple intra-frame encoding and complex inter-frame decoding based on the Slepian-Wolf and Wyner-Ziv distributed source coding theorems. To allocate proper number of bits to each frame, most existing Wyner-Ziv video coding solutions need a feedback channel (FC) at the decoder. However, in many video coding applications, the FC is not allowed. Moreover, the FC will introduce latency and an increase of decoder complexity because several iterative decoding operations may be needed to decode the data to achieve target video quality. The proposed algorithm predicts the number of bits for each Wyner-Ziv frame at the encoder as a function of the coding mode and the quantization parameters. Such predictions will not significantly increase the complexity at the encoder. However, the prediction will be able to properly select the best mode and quantization parameter for encoding each Wyner-Ziv frame. Experimental results show that the proposed algorithms is able to achieve good encoder rate allocation while still maintains consistent coding efficiency. Comparing to the WZVC coder with FC, this new WZVC coder without FC induces only a small loss in Rate-Distortion performance.

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