During the last decades along with the development of asymmetric organocatalysis, tremendous achievements have been made in asymmetric organocatalytic domino or cascade reactions. Herein, the examples of domino or cascade reactions based on asymmetric organocatalyzed Michael addition are described. More specifically, this review aims to cover and discuss the hemi-aminoacetalyzation/acylimminium-cyclization initiated by Michael addition, and the application of this type of reactions in the synthesis of alkaloids.
Statistical downscaling is a process to build up statistical relationships between large-scale (usually 1˚-3˚ on latitude and longitude) climate model outputs and point/watershed-scale meteorological variables. It is an important technique to conduct climate change impact assessment for a specific site or a watershed. This paper systematically reviewed the recent advances in three fields related to statistical downscaling methods: perfect prognosis, model output statistics, and stochastic weather generator. Merits and drawbacks associated with each downscaling method were summarized. In addition, the challenges in progressing statistical downscaling methods were stated, as well as the potential solutions. The contribution of this review is aimed at pointing out the direction of developing statistical downscaling methods and providing clues for climate change impact studies.
In order to find novel biologically active pesticide lead compounds, twenty-one novel 3-[(5-benzylthio-1,3,4-oxadiazol-2-yl)methyl]benzo[d]thiazol(oxazol)-2(3H)-ones were synthesized by 2-benzothiazolinone/benzoxazolone as starting materials via substitution, hydrazine, cyclization and the last benzylation reaction. The structures of the title compounds were characterized by 1 H NMR, IR, EI-MS and elemental analysis. The preliminary bioassay results indicated that most of them showed moderate inhibition activity against Colletotrichum orbiculare, Botrytis cinerea and Rhizoctonia solani at 50 mg/L, and the inhibition rate of compound 5b against Botrytis cinerea and Rhizoctonia solani reached above 85%.
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