Chopin, Jean; Durand, Roger published the artcile< Action of pyridinium perbromide and trimethylphenylammonium perbromide on several 2'-hydroxychalcones>, Recommanded Product: (9Z,12Z)-Methyl octadeca-9,12-dienoate, the main research area is .
The action of the title perbromide compounds in AcOH on I (R = R1 = H) gave I (R = H, R1 = Br), m. 183-5°(BuOH). I (R = H, R1 = Br) was shown to be identical to the product obtained by condensing II (R = H, R1 = Br) with BzH. Treatment of I (R = OMe, R1 = H) under the same conditions with the title perbromide compounds gave almost quant. III (R = Br, R1 = Me), m. 173-5° (benzene), λ (alc.) 294 mμ. Inertness of the bromine indicated nuclear substitution and absence of reaction with FeCl3, cyclization at the phenyl hydroxy group, but neg. reaction with Mg in HCl excluded formation of a heterocyclic 6-membered ring. The action of Br in CCl4 on 2-hydroxy-ω,4,6-trimethoxyacetophenone gave II (R = OMe, R1 = Br), m. 195° (EtOH), λ (alc.) 290 mμ, which, when condensed with BzH, gave I (R = OMe, R1 = Br), m. 149-50° (alc.), λ (alc.) 305 mμ. Thermal cyclization of I (R = OMe, R1 = Br) by the method of Molho, et al. (CA 53, 20043g), gave III (R = Br, R1 = Me), also obtained by action of pyridinium perbromide or of N-bromosuccinimide on III(R = H, R1 = Me). I(R = OMe, R1 = H) was treated with dry HBr gas in AcOH to give starting material, but with I (R = OMe, R1 = Br) there was obtained III (R = Br, R1 = Me), showing that the presence of the nuclear Br was necessary for cyclization. If an AcOH solution of I (R = OMe, R1 = H) is treated in the cold with 40% HBr, there is obtained III (R = R1 = H). Under the same conditions I (R = OMe, R1 = Br) gave III (R = Br, R1 = H). In the presence of 40% HBr in the cold both demethylation and cyclization occur together whether the α-methoxychalcone starting material was brominated or not.
Compt. Rend. published new progress about 112-63-0. 112-63-0 belongs to class esters-buliding-blocks, and the molecular formula is C19H34O2, Recommanded Product: (9Z,12Z)-Methyl octadeca-9,12-dienoate.
Referemce:
Ester – Wikipedia,
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