2403-89-6Relevant articles and documents
A sterically controlled recyclable system: Reversible photoredox reactions between anthraquinone and hindered tertiary amines
Gan, Hong,Whitten, David G.
, p. 8031 - 8037 (1993)
Photochemical reactions of 9,10-anthraquinone (AQ) with sterically hindered tertiary amines have been studied. The reactivity and products are strongly dependent on the structure of the tertiary amine. Irradiation of AQ in the presence of the sterically hindered amine 1,2,2,6,6-pentamethyl-4-piperidinol (3) (or 1,2,2,6,6-pentamethylpiperidine (5)) in degassed dry benzene leads chiefly to the formation of 9-hydroxy-9-[N-(2,2,6,6-tetramethyl-4-piperidinol)-methyl]anthrone (8), which is found to be metastable at room temperature under vacuum. The reaction may be thermally reversed to regenerate the starting materials. The photolysis products and thermal reversion are solvent dependent. While in dry benzene adduct 8 is the major product, in dry acetonitrile the ionic redox products AQH-and iminium cation are detected and no thermal reversal occurs. The results are explained in terms of equilibrium between a product ion pair (AQH-, iminium+) and a metastable adduct 8. In the presence of water, the reaction leads to the formation of a stable product, 9-hydroxy-9-(hydroxymethyl)anthrone (6). Different reactivity is observed upon irradiation of AQ in the presence of the sterically less hindered tertiary amine trans-tropine (1).
Synthetic method of light stabilizer intermediate of 1,2,2,6,6-pentamethyl-4-pipradrol
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Paragraph 0034; 0035; 0041; 0047; 0053; 0064; 0071; 0077, (2018/03/26)
The invention provides a synthetic method of a light stabilizer intermediate of 1,2,2,6,6-pentamethyl-4-pipradrol, and particularly relates to the technical field of light stabilizer preparation. Themethod comprises two step reactions; in the first step, 2,2,6,6-tetramethyl-4-pipradrol and paraformaldehyde are mixed according to a certain proportion and are added into a solvent; stirring is performed for a certain time at the ordinary pressure and a certain reaction temperature, so that the 2,2,6,6-tetramethyl-4-pipradrol completely reacts; then, cooling is performed to reach room temperature; filtering is performed to remove excessive paraformaldehyde; a hydroxymethylated product is obtained; in the second step, a reduction type solid catalyst is charged into a fixed bed reactor; the solvent is added into the reaction liquid; the mixture is continuously introduced into the fixed bed reactor at a certain feeding speed; hydrogen gas is introduced; heating is performed; the reaction liquid continuously flows out from the lower end of the fixed bed reactor; flowing-out reaction liquid is subjected to cooling, gas-liquid separation, liquid filtering, filter liquid solvent steaming removal and purification; the target product is obtained. The synthetic method has the advantages that the preparation is simple and convenient; economic performance and environment-friendly effects areachieved; the product quality is high; the yield is high; the method is suitable for industrial production.
N-Methylation of amine and nitro compounds with CO2/H2 catalyzed by Pd/CuZrOx under mild reaction conditions
Cui, Xinjiang,Zhang, Yan,Deng, Youquan,Shi, Feng
supporting information, p. 13521 - 13524 (2015/01/09)
An active Pd/ZrCuOx catalyst was prepared for the reductive amination of CO2. The N-methylation of amines and nitro compounds with CO2/H2 can be realized with up to 97% yield under relatively mild reaction condi
