1,4-dioxins from methyl phenylchloropyruvate. Competition of the Darzens, Favorskii, and Gabriel reactions

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

“…The dimerization of the phenacyl derivatives 179 , readily obtain-able from α-haloketones and amines, NaOH or Lawesson's reagent, is one of the convenient synthetic route for the preparation of pyrazine [ 394 , 395 , 396 , 397 , 398 ], 1,4-dioxin [ 399 , 400 , 401 ] and 1,4-dithiin [ 402 , 403 ] derivatives 180 ( Scheme 52 ).…”

Tetraphenyl-1,4-dioxin and Tetraphenyl-pyrane-4-one: Old Molecules, New Insights

“…This close contact and the energy match between the states of excited monomer 1 and ground state monomer 2 lets us speculate an intermolecular internal conversion (3) leading to monomer 1 returning to its ground state in a nonradiative manner and monomer 2 reaching its excited state S1. Monomer 2 further relaxes to S1 geometry (4), and since S1 is dark, no fluorescence can be observed (5). The energy must then dissipate by other nonradiative means.…”

“…In 2000, Mamedov and his co-workers investigated the structure of some similar dioxin derivatives by X-ray analysis . They studied two dioxin derivatives: dimethyl 2,5-diphenyl-1,4-dioxine-3,6-dicarboxylate ( 2 ) and dimethyl 2,6-diphenyl-1,4-dioxine-3,5-dicarboxylate ( 3 ) (Figure ).…”

“…In 2000, Mamedov and his co-workers investigated the structure of some similar dioxin derivatives by X-ray analysis. 5 They studied two dioxin derivatives: dimethyl 2,5-diphenyl-1,4-dioxine-3,6-dicarboxylate (2) and dimethyl 2,6-diphenyl-1,4-dioxine-3,5-dicarboxylate (3) (Figure 2 carbonyl group of the methyl ester group, and the lone pairs of "O" atom in the endocyclic ring, whereas the conjugation in dioxin 3 is infeasible due to the nonplanar structure of dioxin. Moreover, the crystal structure of sulfur analogue of dioxin 1; 2,3,5,6-tetraphenyl-1,4-dithiin has been studied by Hoggard and Jones.…”

“…In 2000, Mamedov and his co-workers investigated the structure of some similar dioxin derivatives by X-ray analysis. 5 They studied two dioxin derivatives: dimethyl 2,5-diphenyl-1,4-dioxine-3,6-dicarboxylate ( 2 ) and dimethyl 2,6-diphenyl-1,4-dioxine-3,5-dicarboxylate ( 3 ) ( Figure 2 ). Albeit being regioisomers of each other, these two dioxin derivatives show two very different geometries for the central dioxin ring.…”