Infrared fluorescence sensing of submicromolar calcium: pushing the limits of photoinduced electron transfer

Ozmen, B
Akkaya, EU
A heptamethine cyanine-BAPTA conjugate was synthesized which signals calcium binding by an almost 4-fold increase in the emission intensity at the emission maximum of 782 nm. This significant enhancement factor opens new possibilities for the development of IR fluorescent chemosensors excitable with an inexpensive 780 nm laser diode and detectable with highly sensitive avalanche diodes.


Asymmetric aldol addition of alpha-azido ketones to ethyl pyruvate mediated by a cinchona-based bifunctional urea catalyst
Okumus, Seda; Tanyeli, Cihangir; Demir, Ayhan Sıtkı (Elsevier BV, 2014-07-30)
The first asymmetric synthesis of ethyl 4-aryl-3-azido-2-hydroxy-2-methyl-4-oxobutanoates via a cinchona organocatalyst induced aldol addition of alpha-azido ketones to ethyl pyruvate has been developed. The coupling reaction under optimized conditions was carried out to furnish tetrafunctionalized synthons with enantioselectivities of up to 91:9 and enriched diastereoselectivities of up to 95:5 (syn:anti).
High temperature bromination. Part 12: Bromination of 7-oxabenzonorbornadiene: Synthesis of 2,3-dibromo-7-oxabenzonorbornadiene
Altundas, A; Dastan, A; McKee, MM; Balcı, Metin (Elsevier BV, 2000-08-11)
The electrophilic addition of bromine to 7-oxabenzonorbornadiene (8) at 0 degrees C led in high yield to the formation of dibromoaldehyde 10. However, high-temperature bromination of 8 in carbontetrachloride at 77 degrees C gave non-rearranged products 17 and 18. From the elimination of non-rearranged products, 2-bromo-7-oxabenzonorbornadiene (12) was obtained. Similarly, bromination of monobromide 12 at 77 degrees C yielded the non-rearranged tribromides 19 and 20 while bromination of 12 at 0 degrees C gav...
Distyryl-boradiazaindacenes: facile synthesis of novel near IR emitting fluorophores
Dost, Zeynep; Atilgan, Serdar; Akkaya, Engin U. (Elsevier BV, 2006-09-04)
Boradiazaindacenes with methyl substituents at 3 and 5 positions were for the first time shown to undergo efficient double condensation reactions with an aromatic aldehyde yielding a series of extended conjugation dyes. These new fluorophores have absorption maxima in the range of 650-660 nm. The dyes reported here have large quantum yields with 20 nm Stokes' shifted emission peaks. The straightforward synthesis of such red shifted BODIPY derivatives is important in relation to the synthesis of novel and us...
Indium triflate-catalyzed coupling of indoles with acyl phosphonates: synthesis of bis(indolyl)methane phosphonates
Dasbasi, Teslima; Polat-Cakir, Sidika; Abdullah, Meysun; Demir, Ayhan Sıtkı (Elsevier BV, 2011-05-13)
The coupling reaction of N-methylindole with alkyl and aryl phosphonate is described. The reaction works in the presence of 10 mol % of indium triflate and furnished bis(indolyl)methane phosphonates in good yield and high selectivity.
Synthesis of chiral acetoxy lactones via the Baeyer-Villiger oxidation of cyclic aromatic acetoxy ketones
Demir, Ayhan Sıtkı; Aybey, Asuman (Elsevier BV, 2008-12-01)
The alpha-acetoxylation of indanones and tetralones by using Mn(OAc)(3) followed by the enzyme catalyzed kinetic resolution of acetoxy ketones furnished both of the enantiomers of alpha-acetoxy ketones in good chemical and optical yields. The Baeyer-Villiger oxidation of alpha-acetoxy ketones with m-CPBA, CF(3)SO(3)H, and CH(2)O(2), at rt gives the corresponding lactones without racemization. The acetoxy ketone moiety migrates selectively in order to form lactones. The mild hydrolysis of lactones affords ph...
Citation Formats
B. Ozmen and E. Akkaya, “Infrared fluorescence sensing of submicromolar calcium: pushing the limits of photoinduced electron transfer,” TETRAHEDRON LETTERS, pp. 9185–9188, 2000, Accessed: 00, 2020. [Online]. Available: