39180-42-2

Upstream product

• 784-50-9 fluorenone-2-carboxylic acid 
• 781-73-7 1-(9H-fluoren-2-yl)ethanone 
• 86-73-7 9H-fluorene 

Relevant academic research and scientific papers

General C-H Arylation Strategy for the Synthesis of Tunable Visible Light-Emitting Benzo[a]imidazo[2,1,5-c,d]indolizine Fluorophores

Herein we report the discovery of the benzo[a]imidazo[2,1,5-c,d]indolizine motif displaying tunable emission covering most of the visible spectrum. The polycyclic core is obtained from readily available amides via a chemoselective process involving Tf2O-mediated amide cyclodehydration, followed by intramolecular C-H arylation. Additionally, these fluorescent heterocycles are easily functionalized using electrophilic reagents, enabling divergent access to varied substitution. The effects of said substitution on the compounds' photophysical properties were rationalized by density functional theory calculations. For some compounds, emission wavelengths are directly correlated to the substituent's Hammett constants. Easily introduced nonconjugated reactive functional groups allow the labeling of biomolecules without modification of emissive properties. This work provides a straightforward platform for the synthesis of new moderately bright fluorescent dyes remarkable for their chemical stability, predictability, and unusually high excitation-emission differential.

Photochemical activities of n-nitroso carboxamides and sulfoximides and their application to DNA cleavage

N-Nitroso compounds containing benzene, fluorene or fluorenone rings were synthesized. Photolysis of these compounds with 312-nm UV light provided the NO species, the presence of which was corroborated by use of an EPR method and of 2phenyl-4,4,5,5-tetramethylimidazolin-loxyl 3-oxide (PTIO) as a trapping agent. During irradiation of N-methylN-nitroso-9-fluorenone carboxamide (14c) in the absence of PTIO, it underwent decomposition followed by re-combination to give the heterocyclic nitric oxide radical 15. Incorporation of intercalating moieties endowed the Nnitroso compounds with DNA-cleaving ability through single-strand scission upon UV irradiation in a phosphate buffer (pH 5.0-8.0) under aerobic conditions.

Discovery of potent and stable conformationally constrained analogues of the MCH R1 antagonist SB-568849

A strategy of systematically targeting more rigid analogues of the known MCH R1 receptor antagonist, SB-568849, serendipitously uncovered a binding mode accessible to N-aryl-phthalimide ligands. Optimisation to improve the stability of this compound class led to the discovery of novel N-aryl-quinazolinones, benzotriazinones and thienopyrimidinones as selective ligands with good affinity for human melanin-concentrating hormone receptor 1.

Synthesis and pharmacology of N1-substituted piperazine-2,3-dicarboxylic acid derivatives acting as NMDA receptor antagonists

The binding site for competitive NMDA receptor antagonists is on the NR2 subunit, of which there are four types (NR2A-D). Typical antagonists such as (R)-AP5 have a subunit selectivity of NR2A > NR2B > NR2C > NR2D. The competitive NMDA receptor antagonist

Bichromophoric perylene derivatives: Energy transfer from non-fluorescent chromophores

The energy of excitation at non-fluorescent chromophores such as fluorenone and anthraquinone has been trapped by a fast energy transfer to the highly fluorescent perylene bisimides. To this end, anthraquinone, fluorenone and anthracene derivatives have been linked to the perylene bisimides by non-conjugating spacers and fluorescence quantum yield of such assemblies have been determined as a function of the wavelengths of excitation. Energy transfer in such assemblies is strongly influenced by the orientation of the two chromophores. This is of interest for the construction of fluorescence switches.

INFLUENCE OF THE ANGULAR LINKAGE ON THE MESOMORPHIC PROPERTIES OF CHOLESTERYL ARYLBENZOATES.

Some cholesteryl esters of arylbenzoic acids incorporating angular linkage such as -Co-, -O-, -S-, and -CH//2-, were prepared, and the transition temperatures and heats determined. The cholesteric-isotropic transition temperatures are likely to correlate with the angular correlation parameters of these carboxylic acid moieties. The mesomorphic phenomena are discussed in terms of the molecular structure and electronic effect of these linkages.