On U.V. irradiation, flavanone rearranges to undergoes fragmentation to yield a highly reactive 4-phenyldihydrocoumarin and 2'-hydroxychalcone, and keto-keten.

The product of iodination of the DNA-binding dye Hoechst 33258,4-[5′- (4′′′-methylpiperazin-1′′′-yl)-2′,5′-bi-1H-benzimidazol-2′-yl]phenol (1), has been identified as the monoiodo derivative, i.e. 2-iodo-4-[5′- (4′′′-methylpiperazin-1′′′-yl)-2′,5′-bi-1H-benzimidazol-2′-yl]phenol (2), by mass spectrometry and by comparison of the 1H and 13C n.m.r . spectra of (1) and (2) with those of 2,5-disubstituted benzimidazole model compounds (3) and (4).

A procedure has been developed for linking two terpyridineplatinum(II), Pt(tpy), chromophores by an oligopeptide chain. It relies on the use of a new reagent, succinimido 3- (triphenylmethylthio)propanoate (2), to acylate the amino end groups of an α,ω-diaminoalkane peptide. Subsequent deprotection of the sulfhydryl groups and coupling with [ (tpy )PtlICl ]CI yields the binuclear complexes in good yields. This procedure allowed the synthesis of [ ( tpy )PtS(CH2)2 CO-Gly-Gly-Gly-NH(CH2)3NHCO-(CH2)2SPt(tpy)Cl2 (5b).

Proton nuclear magnetic resonance parameters are reported for Trp-Gly-Ala-Glu, constituting residues 115-118 of bovine myelin basic protein, in dimethyl sulfoxide solution. The 3JNH,α vicinal coupling constants which were used to determine Φ torsional angles, together with the amide proton temperature coefficients, are consistent with a type I ,βturn conformation. Amide proton tempera- ture coefficients obtained for the peptide dissolved in H2O at pH 1.3, 4.6 and 6.5 indicate that the peptide does not adopt any highly preferred folded conformation in water. These findings lend support to previous reports of a reverse turn involving the Trp-Gly-Ala-Glu portion of the encephalitogenic nonapeptide Phe-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Lys from bovine myelin basic protein.

Bei der Belichtung des Flavanons (I) in benzolischer Lösung mit einer 254 nm‐Lichtquelle werden das Dihydrocumarin (II), das Hydroxychalkon (III) und Salicylsäure (IV) erhalten.