The catalytic asymmetric [3 + 2] cycloaddition of 2-indolylmethanols to p-hydroxystyrenes was established in the presence of a chiral phosphoramide, and this reaction provided chiral cyclopenta[b]indole scaffolds in generally high yields and with good enantioselectivities (up to 98% yield, 99:1 er). The control experiments demonstrated that the dual hydrogen-bonding activation mode of the chiral catalyst toward the two substrates played an important role in the reaction. In addition, the large-scale reaction indicated that this catalytic asymmetric [3 + 2] cycloaddition could be scaled up for the synthesis of chiral cyclopenta[b]indole derivatives.

Deep Convolutional Neural Networks (DCNNs) are currently popular in human activity recognition (HAR) applications. However, in the face of modern artificial intelligence sensor-based games, many research achievements cannot be practically applied on portable devices (i.e., smart phone, VR/AR). DCNNs are typically resource-intensive and too large to be deployed on portable devices, thus this limits the practical application of complex activity detection. In addition, since portable devices do not possess high-performance Graphic Processing Units (GPUs), there is hardly any improvement in Action Game (ACT) experience. Besides, in order to deal with multi-sensor collaboration, all previous human activity recognition models typically treated the representations from different sensor signal sources equally. However, distinct types of activities should adopt different fusion strategies. In this paper, a novel scheme is proposed. This scheme is used to train 2-bit Convolutional Neural Networks with weights and activations constrained to {-0.5, 0, 0.5}. It takes into account the correlation between different sensor signal sources and the activity types. This model, which we refer to as DFTerNet, aims at producing a more reliable inference and better trade-offs for practical applications. It's known that quantization of weights and activations can substantially reduce memory size and use more efficient bitwise operations to replace floating or matrix operations to achieve much faster calculation and lower power consumption. Our basic idea is to exploit quantization of weights and activations directly in pre-trained filter banks and adopt dynamic fusion strategies for different activity types. Experiments demonstrate that by using a dynamic fusion strategy, it is possible to exceed the baseline model performance by up to ∼5% on activity recognition datasets like the OPPORTUNITY and PAMAP2 datasets. Using the quantization method proposed, we were able to achieve performances closer to that of the full-precision counterpart. These results were also verified using the UniMiB-SHAR dataset. In addition, the proposed method can achieve ∼9× acceleration on CPUs and ∼11× memory saving.

A Brønsted acid-catalyzed direct C3-arylation of 2-indolylmethanols with tryptamines and tryptophols has been established, leading to a series of potentially bioactive 2,3'-biindole derivatives with a broad substrate scope and generally good yields (38 examples, up to 96% yield). In this process, the reactivity of the C3-position of 2-indolylmethanol is switched from nucleophilic to electrophilic, which can serve as an umpolung strategy in indole chemistry. This protocol not only provides a new strategy for accessing structurally diversified 2,3'-biindolyl frameworks, but also satisfies the requirement of green chemistry.

BACKGROUND Plant disease is one of the most serious problems in agriculture that can damage crops. Chemical fungicides are widely used to control plant diseases, but have led to resistance and a series of environmental problems. It is, therefore, necessary to develop highly effective and eco‐friendly antimicrobial compounds with novel structures. RESULTS A series of novel hydantoin cyclohexyl sulfonamide derivatives were synthesized through an intramolecular condensation reaction. The bioassay results indicated that a majority of the title compounds displayed potent inhibitory activity against Botrytis cinerea, Sclerotinia sclerotiorum and Erwinia carotorora. The in vivo inhibition rate of compound 3h was 91.01% against B. cinerea, which was higher than that of iprodione (84.07%). Compound 3w showed excellent antifungal activity against B. cinerea with a half‐maximal effective concentration (EC50) of 4.80 μg ml–1, which is lower than that of iprodione. Compound 3q had an EC50 value of 1.44 μg ml–1 against S. sclerotiorum, which was close to that of iprodione (1.39 μg ml–1), and the inhibition rate was also similar to that of iprodione. Compounds 3i and 3w had the best inhibition efficacy against S. sclerotiorum, both on growth of the mycelium and sclerotia and in the greenhouse pot test in vitro. Further study showed that compounds 3h, 3r and 3s have superb antibacterial activity against E. carotorora with EC50 values of 2.65, 4.24 and 4.29 μg ml–1 respectively, and were superior to streptomycin sulfate (5.96 μg ml–1). CONCLUSION Because of their excellent antifungal and antibacterial activity against B. cinerea, S. sclerotiorum and E. carotorora, these hydantoin cyclohexyl sulfonamide derivatives could be considered as suitable candidates for new antimicrobial agents. © 2021 Society of Chemical Industry.

The application of 7‐indolylmethanols in catalytic asymmetric reactions has been established via an enantioselective arylation reaction with tryptamines in the presence of chiral phosphoric acid, which afforded a series of structurally diversified chiral 7‐indolylmethanes in moderate to good yields and generally excellent enantioselectivities (23 examples, up to 92% ee). This reaction not only provides a useful strategy for the enantioselective synthesis of chiral 7‐indolylmethanes, but also represents a good example of 7‐indolylmethanol‐involved catalytic asymmetric reaction, which will greatly enrich the chemistry of indolylmethanols.magnified image