- A modular approach to main-chain organometallic polymers
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A highly efficient route to a new class of organometallic polymers containing difunctional N-heterocyclic carbenes has been developed. Bis(imidazolium) halides and divalent group X metals were copolymerized to afford organometallic polymers in up to quant
- Boydston, Andrew J.,Williams, Kyle A.,Bielawski, Christopher W.
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- Carbon Dioxide Mediated Novel Synthesis of Quinazoline-2,4(1H,3H)-dione in Water
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A novel, efficient, and scalable CO2 mediated synthesis of quinazoline-2,4(1H,3H)-dione was developed by a simple cyclization of 2-aminobenzonitrile with DMF in water as the solvent. This is the first report of its kind. DMF was used as the necessary carbon source in the synthesis of quinazoline-2,4(1H,3H)-dione. This synthetic protocol is very efficient; it gives >99% conversion with excellent selectivity. The product was isolated by filtration because of the highly insoluble nature of quinazoline-2,4(1H,3H)-dione in water. The co-product, dimethyl amine, also has industrial importance, and the CO2 that is used can be recycled. This protocol has wide-spread applications in the syntheses of benzimidazole and benzothiazole.
- Rasal, Kalidas B.,Yadav, Ganapati D.
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p. 2067 - 2073
(2016/12/24)
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- Method for synthesizing bis-benzimidazole compound through one-pot method
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The invention provides a method for synthesizing a bis-benzimidazole compound through a one-pot method.According to the method, a bis(ortho-nitroaniline) compound shown in a formula II-1 or II-2 or II-3 and alcohol shown in a formula III are used as raw materials, water and organic solvent are added, and under the effect of a load type multi-metal solid catalyst, the bis-benzimidazole compound shown in the corresponding formula II-1 or II-2 or II-3 is synthesized through the one-pot method, wherein X1, X2, X3, X4, X5, X6, X7 and X8 are H, F, C1, CH3, CH2CH3 and OCH3 or OCH2CH3 independently; X9 is O or CO or CH2 or NH; R1 is H or alkyl or phenyl or alkyl phenyl or alkoxy phenyl, and the number of carbon atoms of alkyl and alkoxy is 1-3; in Y1 and Y2, Y3 and Y4, Y5 and Y6, Y7 and Y8, Y9 and Y10, and Y11 and Y12, one in each group is amino, and the other in each group is nitryl.The method has the advantages that the synthetic route technology is simple, the product yield is high, the production cost is low, the catalyst is easy to separate, high in activity and good in stability, and liquid acid is not used.
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Paragraph 0041; 0042; 0043; 0044; 0045
(2017/01/02)
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- Supercritical methanol as solvent and carbon source in the catalytic conversion of 1,2-diaminobenzenes and 2-nitroanilines to benzimidazoles
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Benzimidazoles and N-methylbenzimidazoles were synthesized by simply heating 1,2-diaminobenzenes in supercritical methanol over copper-doped porous metal oxides. These catalysts were derived from synthetic hydrotalcites that only contain earth-abundant starting materials. The carbon equivalents needed for the construction of the benzimidazole core originated from the solvent itself, which is known to undergo reforming to hydrogen and carbon monoxide through the formation of a formaldehyde intermediate. A variety of 1,2-diaminobenzenes were converted to the corresponding mixtures of benzimidazoles and N-methylated analogues in good yields. Interestingly, the more challenging, but readily available 2-nitroanilines, which require an additional reduction step prior to cyclization, could also be successfully converted to benzimidazoles in high selectivity. Furthermore, various other alcohols were applied besides methanol, to obtain 2-alkyl- and 1,2-dialkylbenzimidazoles. Preliminary mechanistic insights into the origins of N-alkylation as well as the reactivity of the nitro derivatives are discussed.
- Sun, Zhuohua,Bottari, Giovanni,Barta, Katalin
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p. 5172 - 5181
(2015/12/08)
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- N-Substituted Formamides as C1-Sources for the Synthesis of Benzimidazole and Benzothiazole Derivatives by Using Zinc Catalysts
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An efficient and convenient one-pot protocol has been developed for the synthesis of a variety of benzimidazole, benzoxazole, and benzothiazole derivatives. This novel approach uses various o-phenylenediamines and N-substituted formamides (C1 sources) in a zinc-catalyzed cyclization in the presence of poly(methylhydrosiloxane) to afford the corresponding derivatives as sole products in moderate to excellent yields.
- Nale, Deepak B.,Bhanage, Bhalchandra M.
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p. 2835 - 2842
(2015/12/18)
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