ABSTRACT
A palladium/norbornene catalyzed two-component coupling process involving acylation/cyanation of aryl iodides is reported. In this work, aryl acyl nitrile compounds are cleverly selected to provide both nitrile and acyl sources by palladium-catalyzed cleavage of the C-CN bond as both an electrophilic reagent and a termination reagent. This is the first example of C-CN bond cleavage bifunctionalization of aryl iodides. After a series of important NBE derivatives are screened, the products resulting from the bifunctionalization of aryl iodides are smoothly obtained. This strategy has a wide range of substrates and good functional group compatibility. Moreover, this synthetic protocol demonstrated a good application for the synthesis of diverse O,N,C-substituted isoindolinones.
ABSTRACT
A new general synthesis of pharmaceutically important azolo[1,5-a]pyrimidines starting from widely available 3(5)-aminoazoles, aldehydes, and triethylamine is developed. The key is to enable the vinylation reaction that allows the in situ generation of elusive acyclic enamines and the subsequent annulation reaction to occur. This direct and practical strategy is capable of constructing a range of 5,6-unsubstituted pyrazolo[1,5-a]pyrimidines and [1,2,4]triazolo[1,5-a]pyrimidines. More importantly, this protocol provides a concise synthetic route to prepare the clinically used zaleplon.
ABSTRACT
Patch and strip green lands in Harbin with plantation structure of tree + shrub + herb, tree + herb, shrub + herb, tree, shrub, and lawn were selected as studied objects. Through testing PAR, temperature (t), relative humidity (RH), and CO2 concentration in the center and outside of the selected green lands, the ecological functions of the green lands on regulating city microclimate were analyzed. The results showed that except lawn, patch green lands had the function of shading. Green lands with plantation structure of tree + shrub + herb, tree, tree + herb, and shrub had greater effects on lowering temperature, increasing humidity, and adjusting CO2 concentration than that of lawn. Strip green lands also had certain effects on shading, lowering temperature, increasing humidity, and adjusting CO2 concentration. Among different plantation structures of stripe green lands, shrub had the best effect on shading, and tree + shrub had the best effects on lowering temperature, increasing humidity, and adjusting CO2 concentration. The ecological functions of patch green lands were better than those of strip green lands with the same plantation structure, and green lands with multistoried structure had greater ecological effects than those with single layer.
Subject(s)
Carbon Dioxide/analysis , Climate , Ecosystem , Humidity , Temperature , Trees/physiology , China , Urban RenewalABSTRACT
Dust removal by plants was proposed as an important basis of designing urban green space system for future urbanization. Dust removal measurement and leaf surface electron-microscopic scanning were taken for 28 tree species in Harbin city. The results showed that there were obviously different effects of dust removal among different tree species. Picea koraiensis and Juniperus rigida were the ideal conifers for dust removal, and their dust removal abilities were 5.7 g.m-2 and 4.4 g.m-2 after 4 weeks, respectively. Populus alba x berolinensis, Lonicera maackii, and Prunus maackii were the ideal deciduous tree species, and their dust removal abilities were respectively 1.9 g.m-2, 2.0 g.m-2, and 2.45 g.m-2 after 2 weeks. Observation under electronic microscope showed that tree species, having deep channels or dense hair on leaf surface had greater effects of dust removal, while tree species, which had strumose projections on leaf surface, had weaker effects. Different modes of dust removal by plants were also discussed.
