Gilman, Henry published the artcileOxygen-containing heterocycles as liquid scintillator solutes, Recommanded Product: Spiro[fluorene-9,9′-xanthene], the publication is Journal of Organic Chemistry (1958), 361-2, database is CAplus.
cf. C.A. 52, 5424h. Derivatives of dibenzofuran (I), dibenzo-p-dioxin (II) and xanthene were screened as liquid scintillator solutes and the primary-solute relative pulse heights relative to 2,5-diphenyloxazole (arbitrary value 1.00) are tabulated. The biphenyl linkage in I presumably makes all its derivatives superior to corresponding II derivatives The results suggest that the introduction of MeO and dialkylamino groups increases the relative pulse height by shortening the lifetime of the excited state and providing a greater probability that fluorescence will occur before a radiationless transition (C.A. 52, 5382d). The values tabulated indicated that further work on II is promising only with 2-substituted derivatives Cu bronze (4 g.) and 4.0 g. 1-iododibenzo-p-dioxin heated 5 hrs. at 250° (oil bath), the cooled pulverized mixture extracted with hot C6H6 and the concentrated extract diluted with alc. yielded 22% 1,1′-bis(dibenzo-p-dioxin), m. 217-19°. Cu bronze (5 g.) and 4.0 g. 2-iododibenzo-p-dioxin heated 4 hrs. at 240-50°, the cooled pulverized mixture extracted with hot C6H6, the extract chromatographed on Al2O3, the eluate diluted with alc. and the product recrystallized (AcOH) yielded 22% 2,2′-bis(dibenso-p-dioxin), m. 227-30°. Nitrous fumes slowly bubbled 2.5 hrs. through 4.0 g. 2-acetamidodibenzo-p-dioxin in 130 ml. AcOH and 20 ml. Ac2O at 10°, the yellow-green solution poured into 1 l. ice-H2O, the air-dried solid stirred 8 hrs. in 200 ml. dry C6H6 and kept 8 hrs. at room temperature, warmed 1 hr. and the C6C6 evaporated, the concentrated solution chromatographed on Al2O3 and the fraction recrystallized (alc.) gave 16% 2-phenyldibenzo-p-dioxin, m. 108-10°, with characteristic 1,2,4-tri-, 1,2-di-, and monosubstitution bands in the infrared spectrum. Excess PhCH2MgCl added in 15 min. with stirring and gentle refluxing to 5.76 g. 2-benzoyldibenzo-p-dioxin in 100 ml. Et2O, the mixture refluxed 2 hrs., hydrolyzed with saturated aqueous NH4Cl, the dried (Na2SO4) Et2O layer evaporated and the residue crystallized (alc.-H2O) 3 times yielded 60% 1-(2-dibenzo-p-dioxinyl)-1,2-diphenylethanol (III), m. 141-2°. III (3.5 g.) and 15 ml. Lucas reagent (cf. Crawford and Nelson, C.A. 40, 14848) refluxed 2 hrs. in 45 ml. C6H6, the washed (dilute aqueous Na2CO3) C6H6 layer evaporated, the oily residue boiled with ligroine (b. 60-70°) and the solid product crystallized (alc.-H2O) 3 times yielded 33% 2-(α-phenylstyryl)dibenzo-p-dioxin. The use of Lucas reagent renders isolation of III unnecessary since dehydration was effected conveniently using crude carbinol solutions in C6H6.
Journal of Organic Chemistry published new progress about 159-62-6. 159-62-6 belongs to naphthyridine, auxiliary class Other Aromatic Heterocyclic,Spiro, name is Spiro[fluorene-9,9′-xanthene], and the molecular formula is C25H16O, Recommanded Product: Spiro[fluorene-9,9′-xanthene].
Referemce:
https://en.wikipedia.org/wiki/1,8-Naphthyridine,
1,8-Naphthyridine | C8H6N2 – PubChem