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Cyclization of hydroxy-substituted gem-chloronitroso compounds under the action of bases affords cyclic nitronates, namely, isoxazoline N-oxides and 5,6-dihydro-4H-1,2-oxazine N-oxides. The process is reversible, viz., the chloronitroso compounds are regenerated upon the action of hydrogen chloride on the cyclization products. A method for the synthesis of cyclic nitronates from aldols using the title reaction was developed. The cyclization mechanism was studied and the kinetic parameters of the process were determined using UV—Vis and IR monitoring and the results of quantum chemical calculations. [ABSTRACT FROM AUTHOR]

Water is not a good solvent for most organic compounds, yet water can offer many benefits to some organic reactions, hence enriching organic chemistry. Herein, the unique divergent reactivity of 2‐substituted indoles with ⋅NO sources is presented. The amount of water solvent was harnessed for a scalable, benign, and expedient synthesis of indolenine oximes, albeit with water's inability to dissolve the reactants. 2‐Methoxyethyl nitrite, which has been tailored for reactions in water, empowered this protocol by enhancing the product selectivity. We further report on chemoselective transformations of the products that rely on their structural features. Our findings are expected to offer access to an underexplored chemical space. The platform is also applicable to oximinomalonate synthesis. Mechanistic studies revealed the important role of water in the reversal of stability between oxime and nitroso compounds, promoting the proton transfer. [ABSTRACT FROM AUTHOR]

This article discusses recent developments in the photocatalytic reduction of nitro compounds to valuable intermediates, such as amines and azo compounds. Nitro compounds are widely used in various industries but pose environmental and health hazards due to their toxicity and nondegradability. Traditional reduction methods often use harsh conditions and toxic chemicals, making the utilization of photocatalytic organic transformations an attractive option for sustainable and green chemical processes. The article provides an overview of different photocatalytic systems, including metal-organic frameworks, semiconductors, and nanocomposites, and explores their synthesis, performance, stability, recyclability, and selectivity. The use of hole scavengers and sacrificial reagents to enhance the reduction process is also mentioned. The studies demonstrate the potential of these photocatalytic systems for efficient and environmentally friendly nitro compound reduction. [Extracted from the article]