- N -Hydroxyphthalimide/benzoquinone-catalyzed chlorination of hydrocarbon C-H bond using N -chlorosuccinimide
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The direct chlorination of C-H bonds has received considerable attention in recent years. In this work, a metal-free protocol for hydrocarbon C-H bond chlorination with commercially available N-chlorosuccinimide (NCS) catalyzed by N-hydroxyphthalimide (NHPI) with 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ) functioning as an external radical initiator is presented. Aliphatic and benzylic substituents and also heteroaromatic ones were found to be well tolerated. Both the experiments and theoretical analysis indicate that the reaction goes through a process wherein NHPI functions as a catalyst rather than as an initiator. On the other hand, the hydrogen abstraction of the C-H bond conducted by a PINO species rather than the highly reactive N-centered radicals rationalizes the high chemoselectivity of the monochlorination obtained by this protocol as the latter is reactive towards the C(sp3)-H bonds of the monochlorides. The present results could hold promise for further development of a nitroxy-radical system for the highly selective functionalization of the aliphatic and benzylic hydrocarbon C-H.
- Li, Zi-Hao,Fiser, Béla,Jiang, Biao-Lin,Li, Jian-Wei,Xu, Bao-Hua,Zhang, Suo-Jiang
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supporting information
p. 3403 - 3408
(2019/04/01)
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- Method for preparing trimellitic anhydride acid chloride through distillation and purification with film evaporator
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The invention specifically relates to a method for preparing trimellitic anhydride acid chloride through distillation and purification with a film evaporator, belonging to the technical field of organic synthesis of fine chemical intermediates. The method comprises the following steps: with trimellitic anhydride and thionyl chloride as raw materials, carrying out a reflux reaction in a solvent under the action of a tri-n-butylphosphine catalyst so as to obtain a reaction solution after the reaction; subjecting the reaction solution to pressure-reduced distillation to remove the solvent and excess thionyl chloride; and then carrying out distillation, separation and purification with the film evaporator, and carrying out cooling to obtain trimellitic anhydride acid chloride. The method provided by the invention has the advantages of simple process, high product purity, recyclability of the solvent and thionyl chloride, and the like, and is suitable for industrial production.
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Paragraph 0016; 0017; 0018; 0019; 0020; 0021
(2018/09/08)
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- Modular RNA regulators and methods
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This disclosure describes modular miRNA regulator molecules and methods of using modular miRNA regulator molecules. Generally, the modular miRNA regulator molecules include a recognition module and an inhibition module. Generally, the recognition module includes a polynucleotide in which at least a portion of the polynucleotide recognizes at least a portion of a preselected pre-miRNA. Generally, the inhibition module includes a moiety that inhibits nuclease processing of the preselected pre-RNA to a mature RNA.
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Page/Page column 2-3
(2018/10/30)
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- Polyamide-imide with indan structure and preparation method of polyamide-imide
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The invention provides polyamide-imide with an indan structure. The polyamide-imide has a structural formula as shown in the specification, and in the formula, n is from 1 to 8. The invention further discloses a material which is prepared after the polyamide-imide with the indan structure is cured at 220-380 DEG C, and a preparation method of the polyamide-imide with the indan structure. The invention studies the synthesis and the properties of polyamide-imide, thermal-curing polyamide-imide of different polymerization degrees is prepared from 5(6)-amino-1-(4-amino phenyl)-1,3,3-trimethyl indan as monomers, then the stacking density and the interaction of molecular chains can be reduced, the flexibility of the molecular chains can be improved, and finally polyamide-imide resin which is excellent in solubleness and excellent in thermal resistance can be synthesized.
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Paragraph 0048; 0049; 0050; 0051
(2017/08/29)
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- Trimellitic anhydride acid chloride method for the preparation of
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The invention belongs to the technical field of intermediate organic synthesis in fine chemistry, and particularly relates to a preparation method of trimellitic anhydride chloride. According to the method, trimellitic anhydride and thionyl chloride are used as raw materials, reflux reaction is performed on the trimellitic anhydride and the thionyl chloride in a solvent under the effect of an organic alkali catalyst, after reaction, the solvent and excessive thionyl chloride are removed through reduced pressure distillation, then separation and purification are performed through vacuum distillation, and cooling, so that white crystalline solid trimellitic anhydride chloride is obtained. The preparation method has the advantages that the processes are simple, the reaction speed is high, the product yield is high, the purity is high, the solvent and the thionyl chloride can be used repeatedly, the tail gas is easy to treat, and the preparation method is suitable for industrial production of the trimellitic anhydride chloride. The trimellitic anhydride chloride synthesized through the preparation method has the characteristics that the melting point is 67.0-68.8 DEG C, the purity is more than 99 percent, and the reaction yield can reach more than 80 percent.
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Paragraph 0026; 0027
(2016/10/10)
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