- Reaction of 3-Cl/OMe-Substituted 5-Nitrobenzisothiazoles with Hydrazine: Structural and Computational Evidence for Rearrangement Pathways Implicating Intramolecular Formation of Pivotal Meisenheimer Complexes
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In projected structure-activity relationship studies of the novel diheteroarylamide-based anti-HIV agent 2 (1C8), one objective was to evaluate the influence of incorporating the central amide motif in 2 into a five-membered pyrazolone ring, as found in 3. It was envisaged that compound 3 could be prepared through reaction of 3-hydrazino-5-nitrobenzisothiazole 5 with the methyl ester of 4-chloropyridine-3-carboxylic acid, followed by N-methylation of the pyridine nitrogen. However, the reaction of 3-methoxyl-5-nitrobenzisothiazole with hydrazine resulted in formation of ring-opened hydrazonate product 18. In the corresponding reaction with 3-chloro-5-nitrobenzisothiazole, a different rearrangement product 19 was formed, in which two 2,1-benzisothiazole units are joined by a sulfur bridge. Meisenheimer complex formation, favored by the presence of the 5-nitro substituent on the benzisothiazole ring, was postulated to be a key feature in the formation of these deep-seated rearrangement products. Support for the proposed formation of the pivotal Meisenheimer complexes and their subsequent evolution to the observed products in which the benzisothiazole sulfur atom is either expelled or maintained in the isomeric 2,1-benzisothiazole system was obtained by density function theory calculations.
- Lin, Zheng Sonia,Tong, Xing,Patrick, Brian,Kennepohl, Pierre,Grierson, David S.
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- Synthesis of Functionalized Diaryl Sulfides by Cobalt-Catalyzed Coupling between Arylzinc Pivalates and Diaryl Disulfides
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An efficient protocol for the cobalt-catalyzed preparation of diaryl sulfides from solid organozinc pivalates and commercially available diaryl disulfides is reported. This cross-coupling proceeds at room temperature and displays a good functional group tolerance, allowing the preparation of a diversity of symmetrical or asymmetrical diaryl sulfides in 60-95% yield.
- Dong, Zhi-Bing,Balkenhohl, Moritz,Tan, Eric,Knochel, Paul
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supporting information
p. 7581 - 7584
(2018/11/27)
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- A direct preparation of functionalized aryl and heteroaryl disulfides from functionalized zinc organometallics by using sulfur monochloride (S 2Cl2)
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A range of functionalized aryl and heteroaryl disulfides has been prepared from zinc organometallics by using sulfur monochloride (S2Cl 2). The zinc reagents were obtained by transmetalation from magnesium or lithium reagents with ZnBr2.
- Korn, Tobias J.,Knochel, Paul
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p. 1185 - 1187
(2007/10/03)
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- Gas-phase cyclisation reactions of 1-(2-arylthiophenyl)alkaniminyl and 2-(aryliminomethyl)thiophenoxyl radicals
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Flash vacuum pyrolysis (FVP) of the oxime ethers 12-14 and of the sulfides 18-20 at 650°C (10-2-10-3 Torr) gave products derived from the corresponding iminyl and thiophenoxyl radicals. In all cases, benz[d]isothiazoles (e.g., 26) are formed as major products via SHi mechanisms though the yields are greatest with the iminyl precursors. Alternative pathways observed from the thiophenoxyls in specific cases include the formation of the anilinobenzothiophene 36 and of dibenzothiophene 23, via an SHi process and a spirodienyl rearrangement, respectively. There is no evidence for signicant interconversion of the iminyl and thiophenoxyl species.
- Creed,Leardini,McNab,Nanni,Nicolson,Reed
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p. 1079 - 1085
(2007/10/03)
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- Process for preparing aromatic or heteroaromatic sulfur compound
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The present invention provides a process for preparing an aromatic or heteroaromatic thiol represented by the formula (2), the process comprising hydrolyzing an aromatic or heteroaromatic halogenated methyl sulfide represented by the formula (1) wherein Ar is an aromatic or heteroaromatic ring which has no substituent or which has an optional substituent or substituents, X is a halogen atom, m is an integer of 1 to 3 and n is 1 or 2. According to the present invention, an aromatic or heteroaromatic thiol can be prepared at a commercially low cost and with ease.
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- The role of the hydrogen bonding in cycloadditions of benzonitrile oxide with cyanophenols
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The reactivity of aromatic nitriles in cycloadditions with benzonitrile oxide is remarkably enhanced by the ortho-hydroxy substituent. Semiempirical PM3 calculations are in agreement with a hydrogen bonding effect.
- Corsaro, Antonino,Buemi, Giuseppe,Chiacchio, Ugo,Perrini, Giancarlo,Pistara, Venerando,Romeo, Roberto
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p. 7885 - 7892
(2007/10/03)
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- 151. Azidinium-Salze. 24. Mitteilung. Thermolyse heterocyclischer Azidinium-tetrafluoroborate
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The thermolysis of some azidinium salts was investigated.It led to a large variety of products which were isolated or identified by GC/MS.Reaction mechanisms are discussed to explain the product formation.
- Huys-Francotte, Martine,Balli, Heinz
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p. 1679 - 1684
(2007/10/02)
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- Donor-Substituted Benzonitriles as Side-Chain Dienophiles in the Intramolecular Cycloaddition with Inverse Electron Demand
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Expanding the scope of the intramolecular Diels-Alder reaction of 1,2,4,5-tetrazines to include donor-substituted benzonitriles as side-chain dienophiles we describe synthetic routes to novel fused heterotricycles such as the benzofuro-1,2,4-triazi
- Seitz, Gunther,Richter, Joachim
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p. 2177 - 2182
(2007/10/02)
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