Four high triplet organic semi-conductors based on the donor-spiro-acceptor design (D-spiro-A) have been synthesized. Their physicochemical and photophysical properties have been studied, compared and discussed in light of the nature of their respective donor/acceptor units. The four compounds have been used as host materials in efficient sky-blue (EQE 4 10% at 10 mA cm ) phosphorescent organic...

In the title spiro-indeno-quinoxaline compound, C(22)H(14)N(6)O·C(2)H(6)O, the five-membered ring of the indene unit and the pyran ring are perpendicular [89.11 (3)°]. In the crystal, N-H⋯N hydrogen bonds connect the spiro-indeno-quinoxaline mol-ecules, and the ethanol solvent mol-ecules complete the hydrogen-bond network via O-H⋯N and N-H⋯O inter-actions.

A series of functionalized spiro[indoline-3,2'-oxiran]-2-ones was efficiently synthesized by Darzens reaction of phenacyl bromides with isatins both with N-alkyl groups and without N-substituent in the presence of potassium carbonate as a base catalyst. When two equivalents phenacyl bromides were used in the reaction, the N-substitution reaction of isatin also finished with the formation of spi...

The title compound, C(35)H(35)ClN(4)O(3), resulted from a spiro-lactam ring closure of rhodamine B dye. The xanthene ring system is approximately planar [r.m.s. deviation = 0.050 (9) Å for the xanthene ring]. The dihedral angles formed by the spiro-lactam and 5-chloro-2-hy-droxy-benzene rings with the xanthene ring system are 87.9 (7) and 79.1 (7)°, respectively.

7-ethyl-10-hydroxy-camptothecin (SN-38), the active metabolite of the anti-cancer agent irinotecan, contains a lactone ring that equilibrates with a carboxylate form. Since SN-38 lactone is the active and toxic form, it is prudent to examine whether the more soluble carboxylate is a surrogate for SN-38 lactone conjugation. Therefore, relative rates of glucuronidation and isoform specificity of ...

OBJECTIVES A myocardial calcium-independent PLA2 has been described that is activated during myocardial ischemia and this enzyme may modulate ATP-sensitive potassium channels (KATP). The aim of this study was to determine the effect of an inhibitor of this enzyme, a bromoenol lactone, in isolated globally ischemic rat hearts. METHODS Isolated rat hearts were treated for 10 min with 0.3-6 micr...

We show that FRET between Pacific Blue (PB) and Alexa488 (A488) covalently attached to a DNA scaffold can be reversibly controlled by photochromic switching of a spiropyran derivative. With the spiropyran in the closed spiro isomeric form, FRET occurs freely between PB and A488. UV-induced isomerization to the open merocyanine form shuts down the FRET process by efficient quenching of the PB ex...

A highly selective cascade reaction that allows the direct transformation of dienallenes to spirocyclobutenes (spiro[3.4]octenes) as single isomers has been developed. The reaction involves formation of overall four C-C bonds and proceeds via a palladium-catalyzed oxidative transformation with insertion of olefin, olefin, and carbon monoxide. Under slightly different reaction conditions an addi...