Preparation of thermosensitive buprofezin-loaded mesoporous silica nanoparticles by the sol-gel method and their application in pest control.

BACKGROUND: Environmental stimuli-responsive release is one important way to reduce the dosage of pesticide, increase the usage efficiency and improve environmental compatibility. RESULTS: On this basis, we synthesized mesoporous silica nanoparticles (MSNs) and modified them to develop a thermosensitive pesticide controlled release formulation (CRF). In this study, MSNs prepared by the sol-gel method were used as the core, poly (N-IsoPropylAcrylaMide) [P (NIPAM-MAA)] was used as the shell, and buprofezin (Bup) was loaded by adsorption. The prepared Bup@MSNs@P(NIPAM-MAA) could effectively prevent the degradation of buprofezin under UV light and exhibited excellent adhesion to rice leaves. The bioassay results showed that the mortality of Nilaparvata lugens (Stål) treated by Bup@MSNs@P(NIPAM-MAA) was positively correlated with temperature, resulting mainly from the change of release amount of buprofezin caused by temperature variation. Bup@MSNs@P(NIPAM-MAA) had long duration (20 days) for controlling N. lugens, and did not hinder the growth of rice. Meanwhile, Bup@MSNs@P(NIPAM-MAA) had low toxicity to zebrafish and human pneumonocyte BEAS-2B cells. CONCLUSION: This novel thermosensitive pesticide CRF can be applied widely to other insecticides, thus greatly promoting the development of intelligent pesticide formulations. © 2021 Society of Chemical Industry.

Efficient Synthesis of Quinazolinones by Transition-Metal-Free Direct Aerobic Oxidative Cascade Annulation of Alcohols with o-Aminoarylnitriles.

A mild and atom-economic method was developed for direct and efficient synthesis of quinazolinones through a transition-metal-free aerobic oxidative cascade annulation reaction of widely available o-aminoarylnitriles and alcohols. Air could be employed as an effective oxidant under mild conditions, generating water as the only byproduct. Possibly owing to the "cesium effect", the water-soluble base CsOH was found to be crucial in all key steps of the reaction mechanism. Because a wide range of substrates can be used to prepare substituted quinazolinones without contamination by transition-metal residues, this method may be of interest for application in pharmaceutical synthesis. Possible reaction paths were also proposed according to control reactions.

Organotellurium catalysis-enabled utilization of molecular oxygen as oxidant for oxidative deoximation reactions under solvent-free conditions.

Catalyzed by commercially available (PhTe)2, molecular oxygen could be utilized as the mild, cheap and safe oxidant for oxidative deoximation reactions under solvent-free conditions. As the first report on organotellurium-catalyzed deoximation reaction, this work not only provides an efficient deoximation method, but also discloses new features of tellurium catalyst different from those of the organoselenium catalysts.

Copper-Catalyzed Regioselective and Stereoselective Coupling of Grignard Reagents with Pent-1-en-4-yn-3-yl Benzoates: A Shortcut to ( Z) -1,5-Disubstituted Pent-3-en-1-ynes from Accessible Starting Materials.

Copper-catalyzed coupling of Grignard reagents with pent-1-en-4-yn-3-yl benzoates occurs regioselectively at the terminal alkenyl carbon rather than the alkynyl site, leading to the stereoselective formation of unexpected ( Z) -1,5-disubstituted pent-3-en-1-ynes without generation of the initially expected alkenyl allene products. By using easily accessible starting materials, this reaction can provide direct access to thermodynamically unfavorable Z-configured enynes, which widely exist in many bioactive natural products, such as the anti-inflammatory components in henna.

Specific N-Alkylation of Hydroxypyridines Achieved by a Catalyst- and Base-Free Reaction with Organohalides.

A specific N-alkylation of 2-hydroxypyridines is achieved by reacting with organohalides under catalyst- and base-free conditions. The observed HX-facilitated conversion of pyridyl ether intermediates to 2-pyridone products may account for the success and specific N-alkylation of the reaction under the unexpectedly simple conditions. This new reaction may provide a useful alternative for the synthesis of 2-pyridones and analogous structures because of its >99% N-selectivity, relatively broad scopes of both substrates, and no mandatory use of catalysts and bases.

Efficient dehydrative alkylation of thiols with alcohols catalyzed by alkyl halides.

Alcohols can be efficiently converted into the useful thioethers by a transition metal- and base-free dehydrative S-alkylation reaction with thiols or disulfides by employing alkyl halides as the effective catalyst. This simple and efficient method is a green and practical way for the preparation of thioethers, as it tolerates a wide range of substrates such as aryl and alkyl thiols, as well as benzylic, allylic, secondary, tertiary, and even the less reactive aliphatic alcohols.