摘要:
Sitagliptin intermediate compounds of formula (f) and methods of preparation and use thereof are disclosed. Compounds of formula (f) are prepared by the following steps: compounds of formula (a) are subjected to electrophilic reaction with benzyl halides to form compounds of formula (b), which then react with compounds of formula (i) to form novel compounds of formula (e). Gignard agents formed from 2,4,5-trifluoro brmobenzene and magnesium metal react with compounds of formula (e) to afford compounds of formula (f), which are novel intermediates for the preparation of Sitagliptin intermediates of formula (g). Compounds of formula (f) are subjected to reduction by Pd/C, debenzylation, substitution of protecting group to form compounds of formula (g). Compounds of formula (a), (b), (i), (e), (f), and (g) have the following structures, in which R is protecting group of carboxyl and R2 is (substituted) hydrocarbyl.
摘要:
Sitagliptin intermediate compounds of formula (f) and methods of preparation and use thereof are disclosed. Compounds of formula (f) are prepared by the following steps: compounds of formula (a) are subjected to electrophilic reaction with benzyl halides to form compounds of formula (b), which then react with compounds of formula (i) to form novel compounds of formula (e). Gignard agents formed from 2,4,5-trifluoro bromobenzene and magnesium metal react with compounds of formula (e) to afford compounds of formula (f), which are novel intermediates for the preparation of Sitagliptin intermediates of formula (g). Compounds of formula (f) are subjected to reduction by Pd/C, debenzylation, substitution of protecting group to form compounds of formula (g). Compounds of formula (a), (b), (i), (e), (f), and (g) have the following structures, in which R is protecting group of carboxyl and R2 is (substituted) hydrocarbyl.
摘要:
Disclosed is a method for preparing self-dispersing nano carbon black based on a thiol-ene click reaction. A sol-gel technique is used to graft a coupling agent containing a carbon-carbon double bond onto the surface of the carbon black, and a functional molecular chain is grafted onto the surface of the carbon black by a thiol-ene click reaction with a mercapto compound. The self-dispersing nano carbon black is obtained after centrifugation, washing and drying. The method is simple and easy to operate, has a high grafting rate, and can prepare self-dispersing nano carbon black adaptable to different systems by selecting mercapto compounds with different functional groups.
摘要:
Disclosed is a method for preparing self-dispersing nano carbon black based on a thiol-ene click reaction. A sol-gel technique is used to graft a coupling agent containing a carbon-carbon double bond onto the surface of the carbon black, and a functional molecular chain is grafted onto the surface of the carbon black by a thiol-ene click reaction with a mercapto compound. The self-dispersing nano carbon black is obtained after centrifugation, washing and drying. The method is simple and easy to operate, has a high grafting rate, and can prepare self-dispersing nano carbon black adaptable to different systems by selecting mercapto compounds with different functional groups.
摘要:
A drainage pump has an impeller, a motor for driving the impeller, and a pump housing surrounding the impeller. The pump housing has an end wall, a side wall, an inlet, and an outlet. The side wall extends from the end wall. The side wall and the end wall cooperatively define a pump chamber. The inner surface of the side wall has at least one interfering surface for mixing of fluid flowing through the pump housing.
摘要:
A spin transfer oscillator (STO) with a seed/FGL/spacer/SIL/capping configuration is disclosed with a composite seed layer made of Ta and a metal layer having a fcc(111) or hcp(001) texture to enhance perpendicular magnetic anisotropy (PMA) in an overlying (A1/A2)YFeCo laminated field generation layer (FGL). The spin injection layer (SIL) may be laminated with a (A1/A2)XFeCo configuration. The FeCo layer in the SIL is exchanged coupled with the (A1/A2)X laminate (x is 5 to 50) to improve robustness. The (A1/A2)Y laminate (y=5 to 30) in the FGL may be exchange coupled with a high Bs layer to enable easier oscillations. A1 may be one of Co, CoFe, or CoFeR where R is a metal, and A2 is one of Ni, NiCo, or NiFe. The STO is typically formed between a main pole and trailing shield in a write head.
摘要:
Provided are a compound of formula (I), pharmaceutically acceptable salts thereof, preparation methods and applications thereof for inhibiting thrombin, and applications in the treatment and prevention of thrombin-mediated and thrombin-related diseases.
摘要:
A method for measuring the frequency in a spin torque oscillator having at least a magnetic oscillation layer (MOL), junction layer, and magnetic reference layer (MRL) is disclosed. In a first embodiment, a small in-plane magnetic field is applied to the STO after a DC current is applied to excite the MOL into an oscillation state. The MRL has a perpendicular magnetization that is tilted slightly to give an in-plane magnetization component to serve as a reference layer for measuring the oscillation frequency of the MOL in-plane magnetization component. An AC voltage change is produced in the DC current as a result of variable STO resistance and directly correlates to MOL oscillation frequency. Alternatively, a field having both perpendicular and in-plane components may be applied externally or by forming the STO between two magnetic poles thereby producing an in-plane magnetization reference component in the MRL.
摘要:
Disclosed herein is a method for isolating active regions in a germanium-based MOS device. A surface of a germanium-based substrate is covered by a thin polysilicon layer or a poly-SiGe layer, and an isolation structure of germanium dioxide covered by a silicon dioxide layer or a SiGe oxide layer on top is formed by means of two steps of oxidation in a case of the active regions are protected. Such two steps of oxidation using the polysilicon layer or the poly-SiGe layer as a sacrificial layer is advantageous to improve the isolation quality of a fabricated germanium dioxide and to reduce a beak effect occurred during a local field oxygen oxidation so as to dramatically elevate the performance of the germanium device.
摘要:
A heating pump includes an electric motor, a pump housing fixed to the motor, an impeller driven by the motor, and a ring heater with an inner hole for heating fluid in the pump housing. The pump housing has a pump chamber and a pump inlet and a pump outlet which are in fluid communication with the pump chamber. The impeller is received in the pump housing and having an impeller inlet and a plurality of impeller outlets. The ring heater is disposed inside the pump chamber and between the pump inlet and the impeller. The impeller inlet is in fluid communication with the pump inlet via the inner hole.