Based on the structural framework of a pyriproxyfen metabolite, nineteen oxime ester derivatives were synthesized via reaction of the carboxylic acids with 4-(2-(2-pyridinyloxy)ethoxy)benzaldehyde oxime. The corresponding structures were comprehensively characterized by 1H-nuclear magnetic resonance (NMR), 13C-NMR, and electrospray ionization high-resolution mass spectrometry (ESI-HRMS). All of the compounds were screened for their insecticidal activities against Plutella xylostella and Myzus persicae, and for their ovicidal activities against Helicoverpa armigera eggs. The results obtained show that most of the oxime ester derivatives displayed moderate to high insecticidal activities and ovicidal activities at a concentration of 600 μg/mL. In particular, the ovicidal activity of compounds 5j, 5o, 5p, 5q, and 5s was determined to be 100%. Importantly, some of the compounds presented even higher biological activities than the reference compound pyriproxyfen. For example, compound 5j displayed an insecticidal activity value of 87.5% against Myzus persicae, whereas the activity value of pyriproxyfen was 68.3% at a concentration of 600 μg/mL. Among the synthesized compounds 5j and 5s exhibited broad biological activity spectra.

Allolactose (β-D-galactopyranosyl-(1→6)-α,β-D-glucopyranose) is a reducing disaccharide playing important biological role in bacterial metabolism. Two synthetic methods of allolactose including regioselective glycosylation and stepwise synthesis were investigated using D-glucose and D-galactose as the starting materials. The later approach involved a five-spot strategy, 44% overall yields and all the intermediates were easily to be purified, making the route suitable for large scale preparation of the target compound. All the compounds were characterized by NMR and HRMS spectra.

Epilactose (4-O-β-D-galactopyranosyl-D-mannose) is a reducing disaccharide with satisfactory prebiotic properties. A superior synthetic methods were confirmed by screening different coupled donors and acceptors which were synthesized from D-mannose and D-galactose, respectively. This route gets 50% overall yields and all the intermediates are easily to be purified, making the route suitable for large scale preparation of the target compound. All the compounds were characterized by NMR and HRMS spectra.

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