- A Synthesis of 1H-Indazoles via a Cu(OAc)2-Catalyzed N-N Bond Formation
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A facile synthesis of 1H-indazoles featuring a Cu(OAc)2-catalyzed N-N bond formation using oxygen as the terminal oxidant is described. The reaction of readily available 2-aminobenzonitriles with various organometallic reagents led to o-aminoar
- Chen, Cheng-Yi,Tang, Guangrong,He, Fengxian,Wang, Zhaobin,Jing, Hailin,Faessler, Roger
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- Out-Basicity of 1,8-bis(dimethylamino)naphthalene: The experimental and theoretical challenge
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A possibility of non-conventional two-step protonation of 1,8-bis(dimethylamino)naphthalene (proton sponge) is discussed. Unlike the generally accepted mechanism, involving relatively slow direct penetration of a proton into the cleft between the peri-NMe2 groups, it consists of the rapid addition of a proton to the out-inverted NMe2 group with the subsequent slower rotational transfer of the proton into the inter-nitrogen space to produce a stable chelated cation. The following approaches were employed during the work: (1) competitive hydrogen bond formation in a specially designed alcohol in which the OH group might chelate either the proton sponge 1-NMe2 group or another basic center (N,N-dimethylaniline) of known basicity; (2) measuring the basicity of naphtho[1,8-b,c]diazabicyclo[3.3.3] undecane considered to be a close analogue of the proton sponge capable exclusively of out-protonation; (3) X-ray, spectral and DFT studies of structure, energy and stereodynamics of compounds obtained, including their conformers. For the first time, the pKa value of an organic base with a perfectly flat nitrogen atom is reported. The final conclusion is made that both pathways of proton sponge protonation, traditional and non-conventional, contribute in parallel with a still undefined ratio. The estimated out-basicity of the proton sponge is at least 5.5 orders of magnitude lower than the directly measured in-basicity. the Partner Organisations 2014.
- Ozeryanskii, Valery A.,Pozharskii, Alexander F.,Antonov, Alexander S.,Filarowski, Alexander
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p. 2360 - 2369
(2014/04/03)
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- Synthesis of o -(dimethylamino)aryl ketones, acridones, acridinium salts, and 1 H -indazoles by the reaction of hydrazones and arynes
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A novel, efficient route to biologically and pharmaceutically important o-(dimethylamino)aryl ketones, acridones, acridinium salts, and 1H-indazoles has been developed starting from readily available hydrazones of aldehydes and o-(trimethylsilyl)aryl triflates. The reaction proceeds through arynes under mild conditions, tolerates a wide range of functional groups, and provides the final products in good to excellent yields.
- Dubrovskiy, Anton V.,Larock, Richard C.
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p. 11232 - 11256
(2013/02/23)
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- Synthesis of o -(dimethylamino)aryl ketones and acridones by the reaction of 1,1-dialkylhydrazones and arynes
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A novel, efficient route to biologically and pharmaceutically important o-(dimethylamino)aryl ketones and acridones has been developed starting from readily available 1,1-dimethylhydrazones of aldehydes and o-(trimethylsilyl)aryl triflates. The reaction proceeds under mild conditions, tolerates a wide range of functional groups, and provides the final products in good to excellent yields.
- Dubrovskiy, Anton V.,Larock, Richard C.
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p. 4136 - 4139
(2011/10/12)
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