- A Two-Step, One-Pot, and Multigram-Scale Synthesis of N-Difluoromethylthiophthalimide
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A new method for the 100 g scale synthesis of N-difluoromethylthiophthalimide 1 from cheap commodity chemical benzyl mercaptan and HCF2Cl or other difluorocarbene precursors was described. Reagent 1 is an excellent electrophilic difluoromethylthiolating reagent as demonstrated by the gram-scale synthesis of five difluoromethylthiolated derivatives of structurally complicated drug-like molecules and natural products.
- Zhu, Dianhu,Hong, Xin,Li, Dezhi,Lu, Long,Shen, Qilong
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- N -Chlorinative Ring Contraction of 1,4-Dimethoxyphthalazines via a Bicyclization/Ring-Opening Mechanism
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An unprecedented N -chlorinative ring contraction of 1,2-diazines was discovered and investigated with an electrophilic chlorinating reagent, trichloroisocyanuric acid (TCICA). Through optimization and mechanistic analysis, the assisting role of n -Bu 4NCl as an exogenous nucleophile was identified, and the optimized reaction conditions were applied to a range of 1,4-dimethoxyphthalazine derivatives. Also, an improvement of overall efficiency was demonstrated by the use of a labile O -silyl group. A bicyclization/ring-opening mechanism, inspired by the Favorskii rearrangement, was proposed and supported by the DFT calculations. Furthermore, the efforts on scope expansion as well as the evaluation of other electrophilic promoters revealed that the newly developed ring contraction reactivity is a unique characteristic of 1,4-dimethoxyphthalazine scaffold and TCICA.
- Im, Jeong Kyun,Jeong, Ilju,Yang, Byeongdo,Moon, Hyeon,Choi, Jun-Ho,Chung, Won-Jin
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p. 1760 - 1770
(2020/12/30)
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- N-Chlorination-induced, oxidative ring contraction of 1,4-dimethoxyphthalazines
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A rarely explored oxidative ring contraction of electron-rich 1,2-diazine is described. Upon treatment with an electrophilic chlorinating reagent (TCICA), 1,4-dimethoxyphthalazines undergo an N-chlorination-induced ring contraction that is accompanied by the loss of one nitrogen atom. The scope of this unusual reactivity was examined with a range of 1,4-dimethoxyphthalazine derivatives. In addition, a mechanism proceeding via a bicyclic species was proposed on the basis of an isolated reaction intermediate and DFT calculations.
- Im, Jeong Kyun,Yang, ByeongDo,Jeong, Ilju,Choi, Jun-Ho,Chung, Won-jin
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supporting information
(2020/06/03)
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- Organocatalytic Α-trifluoromethylthiolation of silylenol ethers: Batch vs continuous flow reactions
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This work describes the organocatalytic α-trifluoromethylthiolation of silylenol ethers using N-(trifluoromethylthio)saccharin as trifluoromethylthiolating reagent that is activated by the presence of catalytic amounts of a Lewis base. Tetrahydrothiophene was identified as the best organocatalyst and it was successfully employed to promote the synthesis of different α-trifluoromethylketones; the reaction has been performed under a traditional batch methodology and under continuous flow conditions. In general, yields obtained using the traditional batch process were higher than those observed when the reaction was performed under flow conditions. However, short reaction times, higher productivity and higher space time yields were observed when a flow system process was employed. Preliminary DFT calculations were also performed in order to elucidate the mechanism of the reaction.
- Abubakar, Said Said,Benaglia, Maurizio,Rossi, Sergio,Annunziata, Rita
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- Synthesis method of anthranilic acid
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The invention relates to a synthesis method of anthranilic acid. The synthesis method comprises the following steps: (1), putting phthalic anhydride and urea into a reaction container, raising the temperature to 140 DEG C, and stirring; (2), after reaction, adding water, and pulping; (3), adding glacial acetic acid and halogen; (4), stirring at room temperature, reacting for three hours, then filtering to obtain a solid, and putting a mother solution into the next batch of a reaction solution; (5), putting the solid into liquid caustic soda, and stirring at room temperature; (6), adding hydrochloric acid into the reaction solution to adjust the pH to 3-4, and separating out a large amount of solid; and (7), filtering and drying to obtain the product anthranilic acid. The synthesis method has the beneficial effects as follows: a halogenating reaction is directly performed on the halogen and phthalamide, and a reaction solvent can be repeatedly used, so that the halogen utilization rateis very high; use of large amounts of acid and alkali is avoided and generation of large amounts of waste salt and waste water is also avoided; and in addition, the waste water has a COD value of 2,000 or below, so that the environmental pollution is very low and the synthesis method is suitable for industrial production.
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Paragraph 0016
(2018/06/26)
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- Preparation of several active N-chloro compounds from trichloroisocyanuric acid
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A very simple method for the preparation of several activeN-chloro compounds that have extensive applications in organic synthesis, industry, and medicine has been developed.Tetrachloroglycolurils, chloramine-T, N-chlorosaccharin, N-chlorosuccinimide, N-chlorophthalimide, N,N¢-dichlorophenobarbital,and N,N¢-dichlorobarbital were synthesized by chlorination with trichloroisocyanuric acid under mild reaction conditions at roomtemperature. This method is clean, fast, and efficient; the yields are also good to excellent. Georg Thieme Verlag Stuttgart.
- Shiri, Azam,Khoramabadi-Zad, Ahmad
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experimental part
p. 2797 - 2801
(2010/01/21)
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- Conversion of nucleophilic halides to electrophilic halides: Efficient and selective halogenation of azinones, amides, and carbonyl compounds using metal halide/lead tetraacetate
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AlCl3/Pb(OAc)4 and ZnBr2/Pb(OAc) 4 are efficient electrophilic N- and α-C-halogenating agents. A variety of azinones, amides and carbonyl compounds were chemoselectively and regioselectively N-, or α-C-halogenated in good to excellent yield using AlCl3/Pb(OAc)4 and ZnBr2/Pb(OAc)4 in acetonitrile. Georg Thieme Verlag Stuttgart.
- Kim, Jeum-Jong,Kweon, Deok-Heon,Cho, Su-Dong,Kim, Ho-Kyun,Lee, Sang-Gyeong,Yoon, Yong-Jin
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p. 194 - 200
(2007/10/03)
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- Radical Addition of N-Chlorophthalimide and N-Bromophthalimide to Alkenes
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The addition of N-chlorophthalimide (1b) to alkenes 3 via phthalimidyl radicals introduces a chlorine atom and an imidyl moiety to vicinal C-atoms of a carbon chain. The yields depend on the substituents of the alkene 3. The regioselectivity can be explained by steric and electronic effects; differences in the behavior of the addition of N-chlorophthalimide (1b) and N-bromophthalimide (1a) can be explained by a reversible attack of the phthalimidyl radical to the double bond.
- Kirsch, Andre,Luening, Ulrich
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p. 129 - 134
(2007/10/03)
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- Process for preparing N-chloroimides
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N-chlorophthalimide, N-chlorosuccinimide, and N-chloroglutarimide are prepared by contacting the corresponding imide with molecular chlorine under substantially non-aqueous conditions in an inert organic solvent in the presence of a poly(4-vinylpyridine)-divinylbenzene copolymer.
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- Process for preparing n-chlorophthalimide
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N-Chlorophthalimide is prepared by contacting an alkali metal salt of phthalimide with chlorine under substantially non-aqueous conditions in the presence of a halogenated aliphatic hydrocarbon and at a temperature of from about -10° C. to about +40° C.
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