Synthesis of 3-(Pyridin-2-yl)quinazolin-2,4(1H,3H)-diones via Annulation of Anthranilic Esters with N-pyridyl Ureas.

A new route for the synthesis of quinazolin-2,4(1H,3H)-diones and thieno [2,3-d]pyrimidine-2,4(1H,3H)-diones substituted by pyridyl/quinolinyl moiety in position 3 has been developed. The proposed method concluded in an annulation of substituted anthranilic esters or 2-aminothiophene-3-carboxylates with 1,1-dimethyl-3-(pyridin-2-yl) ureas. The process consists of the formation of N-aryl-N'-pyridyl ureas followed by their cyclocondensation into the corresponding fused heterocycles. The reaction does not require the use of metal catalysts and proceeds with moderate to good yields (up to 89%). The scope of the method is more than 30 examples, including compounds with both electron-withdrawing and electron-donating groups, as well as diverse functionalities. At the same time, strong electron-acceptor substituents in the pyridine ring of the starting ureas reduce the product yield or even prevent the cyclocondensation step. The reaction can be easily scaled to gram quantities.

Synthesis and anti-inflammatory evaluation of N-sulfonyl anthranilic acids via Ir(III)-catalyzed C-H amidation of benzoic acids.

The iridium(III)-catalyzed ortho-C-H amidation of benzoic acids with sulfonyl azides is described. These transformations allow the facile generation of N-sulfonyl anthranilic acids, which are known as crucial scaffolds found in biologically active molecules. In addition, all synthetic products were evaluated for in vitro anti-inflammatory activity against interleukin-1ß (IL-1ß) and cyclooxygenase-2 (COX-2) with lipopolysaccharide (LPS)-induced RAW264.7 cells. Notably, compounds 4c and 4d, generated from p-OMe- and p-Br-sulfonyl azides, were found to display potent anti-inflammatory property stronger than that of well-known NSAIDs ibuprofen.

A spectroscopic study of substituted anthranilic acids as sensitive environmental probes for detecting cancer cells.

Small-molecule fluorescent reporters of disease states are highly sought after, yet they remain elusive. Anthranilic acids are extremely sensitive environmental probes, and hold promise as general but selective agents for cancer-cell detection if they can be equipped with the appropriate targeting groups. The optical properties of a small library of N-isopropyl invariant anthranilic acids were investigated in methanol and chloroform. Points of variation included: fluoro, trifluoromethyl, or cyano substitution on the aromatic ring, and derivitization of the parent carboxylic acid as esters or secondary carboxamides. Phenylboronic acid conjugation at the carboxylic acid alongside un-, mono-, and dimethylated 2-amino groups was also explored. The boron-containing anthranilic acids were also evaluated as sensitive fluorescent probes for cancer cells using laser scanning confocal microscopy. In general, the compounds produced blue fluorescence that was strongly influenced by substitution and environment. 4-Trifluoromethyl and 4-cyano esters proved to be the most sensitive environmental probes with quantum yields as large as 100% in chloroform, and enhancements of up to 30-fold on going from methanol to chloroform. Stokes shifts ranged from 63 to 120nm, generally increasing with ortho-substitution and environmental polarity. It was demonstrated that phenylboronic acid conjugation was an attractive method for cancer cell detection via boronate ester formation with overexpressed glycoproteins (with no interference from normal, healthy cells), presumably due to favorable boron-sialic acid interactions.