Photochemistry of stilbenyl-pyrroles: a new approach to indole and isoindole derivatives

Synthesis and spectroscopic characterisation of BODIPY® based fluorescent off–on indicators with low affinity for calcium

“…Two BODIPY R -APTRA derivatives were synthesized, namely, the caesium salts of 4,4-difluoro-8-(3-hydroxy-4-aminophenyl-N,N,O-triacetate)-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene (12) and 4,4-difluoro-8-(3-hydroxy-4-aminophenyl-N,N,Otriacetate)-3,5-bis-(4-methoxyphenyl)-4-bora-3a,4a -diazas -indacene (13). Absorption, excitation and emission spectra of these indicators were measured at 20 • C in 100 mM KCl aqueous buffered solution, pH 7.20, as a function of Ca 2+ concentration.…”

“…1 H, 13 C and DEPT NMR spectra were recorded on a Bruker-300 Avance instrument operating at a frequency of 300 MHz for 1 H and 75 MHz for 13 C. All spectra were recorded in CDCl 3 . The 1 H chemical shifts are reported in ppm relative to tetramethylsilane (0.00 ppm), using the residual solvent signal as an internal reference and 13 C shifts with CDCl 3 (77.67 ppm) as internal standard. Chemical shift multiplicities are reported as s = singlet, d = doublet, t = triplet, q = quartet and m = multiplet.…”

“…Arylated pyrroles were prepared by Stille reaction of N-Bocpyrrole tin derivative 5. 13 The latter compound was prepared according to a described procedure 14 from N-Boc-pyrrole (4) by lithiation, using 2,2,6,6-tetramethylpiperidine lithium and subsequent quenching of the lithium derivative by tributyltin chloride. Stannane 5 was coupled with iodoanisole, giving N-Boc-2-(4-methoxyphenyl)pyrrole 15 (6), according to a published procedure.…”

Metalated heterocycles in organic synthesis: Recent applications

“…2-Stannylpyrroles, prepared by direct 2-lithiation of the corresponding N-protected heterocycles and reaction with a chlorostannane, have been employed recently for cross-coupling reactions with aryl halides in the synthesis of stilbenylpyrroles, 321 calixpyrroles, 322 pyrrole-based polymers, 323 compounds against cocaine abuse 324 and fluorescence indicators. 325 An example of generation and use of this stannylated pyrroles is shown in Scheme 52, with the N-lithium-2,2,6,6-tetramethylpiperidine-promoted lithiation of N-Boc-pyrrole, followed by stannylation to give 2-stannylpyrrole 170.…”

Synthesis and photochemistry of β-(3-substituted-2-furyl)-o-divinylbenzenes; [2+2] and [4+2] intramolecular cycloadditions

“…[1][2][3][4][5][6][7][8][9][10] This work has been extended to furan (1b) [11][12][13][14][15][16] and pyrrole (1c) [17][18][19][20][21] analogues. It has been found that contrary to o-vinylstilbene (1a), which undergoes an intramolecular [2+2] photocycloaddition that generates benzobicyclo[2.1.1]hexene structure (2), the furano analogue (1b) gives benzobicyclo[3.2.1]octadiene structure (3a) while the pyrrolo analogue (1c) reacts completely different and is transformed into an intermolecular adduct.…”