Acylnitroso compounds (acylnitroso compounds) are one of the more active nitroso compounds, which have been widely used in the [4 + 2] cycloaddition reaction of conjugated dienes since 1973. This type of hetero Diels-Alder reaction is an important method for the synthesis of natural products such as polyhydroxyalkaloids and oxazine derivatives.
Acyl nitroso compounds are usually prepared by oxidizing acyl hydroxylamine in situ using periodate, lead dioxide, hypochlorite and other oxidizing agents. However, these oxidants are highly toxic, the reaction conditions are harsh, and there are many side reactions. In recent years, people have used ruthenium (Ru), copper (Cu), iron (Fe) and other transition metals to catalyze the oxidation of acyl hydroxylamine to prepare acyl nitroso compounds. Although this method has mild reaction conditions and high yield, it has the disadvantages of difficult catalyst preparation, the need for additional ligands, and a large amount of catalyst.
The research team of Lu Chongdao, a researcher at the Xinjiang Institute of Physics and Chemistry, Chinese Academy of Sciences, used rhodium caprolactam [Rh2 (cap) 4] as the catalyst and tert-butoxy peroxybutanol (TBHP) as the oxidant to catalyze and oxidize the acyl hydroxylamine at room temperature. Diels-Alder reaction of the acyl nitroso compound with the conjugated diene yields the cycloaddition product of [4 + 2] (see figure). The method has the advantages of simple operation, mild reaction conditions, low catalyst consumption and high reaction yield.
Related research results were published in the recently published Synlett (2012, 23 (12): 1801-1804).
Reaction process diagram
Modern chairs and sofas have simple yet sophisticated designs that emphasize clean lines and geometric shapes. They often feature a minimalist aesthetic, with a focus on functionality and visual appeal. The design may incorporate elements such as smooth curves, angular frames, and asymmetrical details.
Modern chairs and sofas are made from a variety of materials, including but not limited to leather, fabric, metal, and wood. The choice of materials can impact the overall look and feel of the furniture piece. For example, leather upholstery can provide a sleek and luxurious touch, while fabric upholstery offers a softer and more versatile option.
Despite their contemporary appearance, modern chairs and sofas prioritize comfort. They often feature padded seats, backrests, and armrests for optimal relaxation. Ergonomic designs and high-quality cushioning materials contribute to a comfortable seating experience.
Modern chairs and sofas often utilize neutral colors or monochromatic tones, such as white, black, gray, or beige. However, bold and vibrant colors can also be incorporated as accent pieces or to create a statement in the space.
Modern Chair And Sofa,Modern Armchairs,Comfortable Modern Sofa,Modern Chair,Modern Sofa Chair
Ningbo Greenly Industy Co.,LTD. , https://www.chinagreenly.com