The mechanism of the electrochemical oxidation of 2,5-dihydroxybenzoic acid and 3,4-dihydroxybenzaldehyde in the presence of 3-hydroxy-1H-phenalene-1-one as a nucleophile has been studied in water/acetonitrile (80/20 v/v) solution using cyclic voltammetry and controlled-potential coulometry methods. The results indicate that the quinones derived from oxidation of 2,5-dihydroxybenzoic acid and 3...

Mushroom tyrosinase, which is known to convert a variety of o-diphenols into o-benzoquinones, has been shown to catalyse an unusual oxidative decarboxylation of 3,4-dihydroxymandelic acid to 3,4-dihydroxybenzaldehyde [Sugumaran (1986) Biochemistry 25, 4489-4492]. The mechanism of this reaction was re-investigated. Although visible-region spectral studies of the reaction mixture containing 3,4-d...

Three new bromophenols, 2,2',3,6,6'-pentabromo-3',4,4',5-tetrahydroxydibenzyl ether (1), bis(2,3,6-tribromo-4,5-dihydroxyphenyl)methane (2), and 2,2',3,5',6-pentabromo-3',4,4',5-tetrahydroxydiphenylmethane (3), were isolated from the red alga Symphyocladia latiuscula. Two bromophenols, 2,3,6-tribromo-4,5-dihydroxymethylbenzene (4) and 2,3,6-tribromo-4,5-dihydroxybenzaldehyde (5), were also repo...

Determination of molybdenum(VI) by direct spectrophotometry and simultaneous determination of molybdenum(VI) and titanium(IV) are reported. Molybdenum(VI) gives a golden yellow colour with 2,4dihydroxybenzaldehyde isonicotinoyl hydrazone with a 1:2 metal-reagent stoichiometry at pH 1.5. The complex shows an absorption maximum at 445 nm with molar absorptivity and Sandell's sensitivity of 1.02x1...

The first organocatalytic asymmetric synthesis of smyrindiol, by using an (S)-proline catalyzed enantioselective intramolecular aldol reaction as the key step, is described. Smyrindiol was synthesized from commercially available 2,4-dihydroxybenzaldehyde in 15 steps, with excellent stereoselectivity (de = 99%, ee = 99%). In the course of this total synthesis a new and mild coumarin assembly was...