Phthalaldehyde 4,5-dimethoxy

On treatment with acids or bases, both the monomethoxy and the dimethoxy six-membered ring peroxide are converted into the methyl ester of o-phthalaldehydic acid or into o-phthalaldehydic acid, depending on the reaction conditions. Oxidation with hydrogen peroxide yields o-phthalic acid.87 The hydrogenation of 135 in the presence of a Lindlar catalyst leads to o-phthaldialdehyde (yield =... 

Keywords orf/to-Phthalaldehyde/ 3,4-dimethoxy ori/to-phthalaldehyde, amines, isonitriles, NaHS03, DMSO-H2O (1 1), room temperature, one-pot three-component reaction, 1-car-boxamido-3-oxoisoindoles... 

A mixture of orf/to-phthalaldehyde (1 0.41 mmol 1 equiv.) and NaHSOs (0.85 mmol 2 equiv.) dissolved in DMSO-H2O (1 mL/1 mL) in the reaction flask with was reacted for 0.5 h at room temperature, followed addition of by 1.0 equiv. of amine 2 and 2.0 equiv. of isonitrile 3. The whole reaction mixture was then allowed to stir for overnight at room temperature. Thereafter, the reaction mixture was diluted with 30 mL ethyl acetate and extracted with saturated ammonium chloride (3x15 mL). The organic layer was dried over sodium sulfate, evaporated under vacuum and the crude product was purified using column chromatography to obtain lOcarboxamido-isoindole 4. In case of 3,4-dimethoxy ort/io-phthalaldehyde addition of another solvent, acetonitrile is needed (i.e. DMSO-H2O-CH3CN (4 4 1 v/v/v). All the isolated products of isoindoles were characterized on the basis of spectral studies. 

FIGURE 2.1 Reagents for introducing a fluorophore into compounds with a complementary reactive functional group. Reagents 1 = dansyl chloride 2 = dabsyl chloride 3 = dansyl hydrazine 4 = fluorescamine 5 = 2,4-dihydro-6,7-dimethoxy-4-methyl-3-oxo-quinoxaline-2-carbonyl azide 6 = o-phthalaldehyde 7 = fluorenyhnethyloxycarbonyl chloride 8 — 4-bromome iyl-7-methoxycoumarin and 9 = 4-chloro-7-nitrobenzofurazan. 

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