Thiophene-anthrones

Anthraquinone dyes, 1, 331-332 Anthra[ 1,2-c][ 1,2,5]selenadiazole-6,11 -dione X-ray crystal structure, 6, 516 Anthra[2,3-6]thiophenes synthesis, 4, 905 Anthrazoline polymers, 1, 297 Anthrone, pyrazolo-, 1, 320 Anthrones, 1, 336-337... 

Phenylmagnesium bromide is prepared in the usual manner [Org, Syntheses Coll. Vol. 1, 550 (1941)] from 52 g. (0.33 mole) of bromo-benzene and 7.2 g. (0.30 gram atom) of magnesium. To the solution of the Grignard reagent in ether is added a solution of 38.8 g. (0.2 mole) of anthrone [Org. Syntheses Coll. Vol. 1, 60 (1941)] in dry thiophene-free benzene. Excess ice and dilute hydrochloric acid are added, the ether layer is separated, and the aqueous layer is extracted with ether. The combined ethereal solutions are washed with 12% aqueous alkali solution and water. The ether is evaporated, and the residue is steam-distilled. The residue from the steam-distillation vessel is taken up in ether, and the ether is evaporated. The residual syrup is heated with a mixture of 12% aqueous sodium hydroxide and 10 g. of sodium hydrosulfite. The mixture is cooled and diluted with ether the alkaline aqueous layer is separated and discarded the ethereal layer is washed thoroughly with water and the ether is evaporated. The residual 9-phenylanthracene is reciystallized from acetic acid to give 36 g. (71%) of product, m.p. 152-153°. 

The reactions of thienothiophene derivatives in the absence of a solvent were also described. For example, the solid-state thermally induced rearrangement of 9,10-dihydroxy-9,10-bis(thieno[3,2- >]thiophen-2-yl)-9,10-dihydroanthracene (275) occurs at 240 °C and gives 10,10-bis(thieno[3,2- >]thiophen-2-yl)anthrone (276) (2000JA1082). 

In order to study the keto-enol tautomerism of thiophen analogues of anthrone, three of the monothieno-analogues (412)—(414) and five of the... 

Thiophen Analogues of Anthracene and Phenantbrene.— The remaining member (237) of the thieno-analogues of anthrone-anthrol has been synthesized from the known (238) by reduction of one of the carbonyl groups to the ketal, followed by... 

Theoretical methods have been applied to elucidate tautomeric equilibria. In agreement with the experimental finding, the A -thiolen-2-one (44a) was calculated to be more stable than the hydroxythiophen (44). Tautomeriza-tion of thiophen analogues of anthrone, e.g. (45), was discussed in the light of the differences in HMO energies. ... 

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