The reaction mechanism between propadienylidene and ethylene has been systematically investigated employing the B3LYP/6-311??G** and MP2/cc-pVTZ levels of theory to better understand the reactivity of propadienylidene with unsaturated hydrocarbons. Geometry optimization, vibrational analysis, and energy property for the involved stationary points on the potential energy surface have been calculated. Two important initial reaction complexes characterized by three-and four-membered ring structures have been located firstly. After that, three different products possessing three-, four-, and five-membered ring characters have been obtained through three reaction pathways. In the first reaction pathway, a threemembered ring alkyne compound has been obtained. As for the second reaction pathway, it is a diffusion-controlled reaction, resulting in the formation of the four-membered ring conjugated diene compound. A five-membered conjugated diene compound has been obtained in the third reaction pathway, which is the most stable product in the available products thermodynamically. On the other hand, the second reaction pathway is the most favorable reaction to proceed kinetically.

Patient’s poor compliance and the high risk of toxic effects limit the clinical use of galantamine hydrobromide. To overcome these drawbacks, the sustained-release galantamine pamoate microspheres (GLT-PM-MS) were successfully developed using an oil/water emulsion solvent evaporation method in this study. Physicochemical properties of GLT-PM-MS were carefully characterized, and the in vitro and in vivo drug release behaviors were well studied. Results showed that the morphology of optimized microspheres were spherical with smooth surfaces and core-shell interior structure. Mean particle size, drug loading and entrapment efficiency were 75.23 ± 1.79 μm, 28.01 ± 0.81% and 87.12 ± 2.71%, respectively. The developed GLT-PM-MS were found to have a sustained release for about 24 days in vitro and the plasma drug concentration remained stable for 17 days in rats. These results indicated that GLT-PM-MS could achieve the sustained drug release purpose and be used in clinical trial.

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The mechanism of insertion reaction between phosphenium cation and azirane has been investigated theoretically in order to better understand the reactivity for the valence isoelectronic of carbene. Phosphenium cation acts as an electrophilic reagent and accepts ? electrons of azirane to form a complex in the first combination step. The greater the positive charge on phosphorus in phosphenium cation, the more stable the formed complex is. Introduction of substituents will decrease positive charge on phosphorus in phosphenium cation. The order of positive charge on phosphorus is HP+-F > HP+-OH > HP+-NH2, which is consistent with their Lewis acidities. The complex transforms to a four-membered ring product via a transition state in the second insertion step. The product is more stable than the complex due to the decrease of ring extension.