The crystal structures of the title compounds, C19H19NO and C31H34N2O, were determined as part of an experiment in an undergraduate teaching laboratory that demonstrates the relationship between mol-ecular structure and function. 1',3',3'-Tri-methyl-spiro-[chromene-2,2'-indoline] is both a photoswitch and thermochromic mol-ecule. Students synthesized it and a bis-indoline adduct and compared th...

The effects of cisplatin binding to DNA were explored at the nucleosome level to incorporate key features of the eukaryotic nuclear environment. An X-ray crystal structure of a site-specifically platinated nucleosome carrying a 1,3-cis-{Pt(NH₃)₂}²+-d(GpTpG) intrastrand cross-link reveals the details of how this adduct dictates the rotational positioning of DNA in the nucleosome. Results from in...

The new binuclear chromium Pacman complex [Cr2(L)] of the Schiff base pyrrole macrocycle H4L has been synthesized and structurally characterized. Addition of isocyanide, C≡NR (R = xylyl, tBu), or triphenylphosphine oxide donors to [Cr2(L)] gives contrasting chemistry with the formation of the new coordination compounds [Cr2(μ-CNR)(L)], in which the isocyanides bridge the two Cr(II) centers, and...

Z. Naturforsch. 34b, 569-572 (1979); received December 27, 1978 Triphenylphosphazenyl Derivatives, Preparation, Characterization Reaction of the ring systems NPC12(NS0X)2 and (NPC12)2NS0X (X = F, Cl, Ph) with HNPPI13 in molar ratio 1:2 gives their mono(tripbenylphosphazenyl) derivatives. The compound NPCl(NPPh3)(NSOPh)2 forms a stable 1:1 adduct with acetonitrile. All compounds are characterize...

Addition of 5-substituted dithianyl anions to carbonyl compounds normally produces trans adducts. The presence of a nucleophilic hydroxymethyl group in position 5 dramatically decreases the trans stereoselectivity of the reaction in THF. The trans/cis ratio shows a bell curve dependence on HMPA, fitted to a quantitative model involving a series of equilibrated ion pairs, of which an intermediat...

Many hypotheses have been developed to explain aging and age-related neurodegenerative disorders; one of the most compelling is the role of oxidative stress to induce changes in protease activity in brains of patients of Alzheimer's disease and prion disease. At the moment however, there is no clear answer how protein degradation may be achieved in the brain. We have observed that several metal...

compounds, the identification of the cofactor in the AOs was not an easy task, involving derivatization of the enzyme-bound cofactor with carbonyl reagents to form a stable adduct, followed by detailed characterization of active site cofactor-containing peptides using spectroscopy, mass spectroscopy and NMR (Ref. 9). Consistent with these advances on AOs and related quinoproteins, the possibili...

In the Baylis-Hillman reaction of aryl aldehydes with phenyl vinyl ketone we have observed exclusive formation of diadducts 4, and that the yields of diadduct can reach 80% with increasing amounts of phenyl vinyl ketone. On the other hand, for phenyl acrylate and phenyl thioacrylate, only the normal Baylis-Hillman adduct was obtained. The effects of substituents were also examined and a plausib...

The stereochemical factors that influence the tendencies for sequence specific binding of platinum antitumour drugs to DNA are examined. The NHs of the platinum-amine moiety can form hydrogen bonds to the O6 of guanine or to a phosphate oxygen of DNA. Modelling the stereochemistry of the NH atoms can lead to compounds with a strong preference for forming one type of adduct with DNA.

By using FMN enriched in (13)C (90%) at position C-4a, we have conclusively shown that the reaction of molecular oxygen with bacterial luciferase-bound FMNH(2) forms an adduct at the 4a position. Consistent with this are (13)C NMR studies of FMN and other flavin compounds which show that this carbon should be unusually reactive in the reduced 1,5-dihydroflavins with respect to electrophilic att...