Transformations of epoxyketones of the carane series using bases

Conclusions -3,4-Epoxycarane-2,5-dione when treated with alcoholates and alkali in alcohol forms 3,6,6-trimethyl-2-oxobicyclo[3. 1. 0]-3-hexen-4-yl-formic acid and-3,4-epoxycaran-2-on-5-ol, whereas in dioxane the first product is formed exclusively.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 677–679, March, 1984.     

Photoinduced carbon monoxide migration in a synthetic heme-copper complex

Time-resolved infrared (TRIR) flash photolytic techniques have been employed to initiate and observe the efficient dissociation of CO from a synthetic heme-CO/copper complex, [((6)L)Fe(II)(CO)..Cu(I)](+) (2), in CH(3)CN and acetone at room temperature. In CH(3)CN, a significant fraction of the photodissociated CO molecules transiently bind to copper (nu(CO)(Cu) = 2091 cm(-)(1)) giving [((6)L)Fe(II)..Cu(I)(CO)](+) (4), with an observed rate constant, k(1) = 1.5 x 10(5) s(-)(1). That is followed by a slower direct transfer of CO from the copper moiety back to the heme (nu(CO)(Fe) = 1975 cm(-)(1)) with k(2) = 1600 s(-)(1). Additional transient absorption (TA) UV-vis spectroscopic experiments have been performed monitoring the CO-transfer reaction by following the Soret band. Eyring analysis of the temperature-dependent data yields DeltaH(double dagger) = 43.9 kJ mol(-)(1) for the 4-to-2 transformation, similar to that for CO dissociation from [Cu(I)(tmpa)(CO)](+) in CH(3)CN (DeltaH(double dagger) = 43.6 kJ mol(-)(1)), suggesting CO dissociation from copper regulates the binding of small molecules to the heme within [((6)L)Fe(II)..Cu(I)](+)(3). Our observations are analagous to those observed for the heme(a3)/Cu(B) active site of cytochrome c oxidase, where photodissociated CO from the heme(a3) site immediately (ps) transfers to Cu(B) followed by millisecond transfer back to the heme.     

The triterpene glycosides ofpatrinia intermedia roem et schult

Conclusions It has been established that patrinoside D₁ is the -D-glucopyranosido(13) -D-xylopyranosido(12) -L-rhamnosido(14)--D-xylopyranoside (13) of oleanolic acidKhimiya Prirodnykh Soedinenii, Vol. 5, No. 2, pp. 84–89, 1969     

Efficient photodissociation of O2 from synthetic heme and heme/M (M = Fe, Cu) complexes

Single wavelength excitation (lambdaex = 355 or 532 nm) of low-temperature stabilized (198 K) synthetic heme-dioxygen and heme-dioxygen/M complexes, where M = copper or iron in a non-heme environment, results in the dissociation of dioxygen as indicated by the generation of the ferrous heme (Soret band, 427 nm) and the bleaching of the ferric-superoxide (FeIII(O2-)) 410-nm Soret band in the transient absorption difference spectrum. Dioxygen rebinds to the four heme complexes studied with comparable rate constants ( approximately 6-9 x 105 M-1 s-1). However, the quantum yield for complete dissociation of O2 from our simplest heme-O2 complex (F8)FeIII(O2-) (phi = 0.60) is higher than the other complexes measured (phi = approximately 0.2-0.3) as well as that for oxy-myoglobin (phi = 0.3).     

Bounds on the cover time

Consider a particle that moves on a connected, undirected graphG withn vertices. At each step the particle goes from the current vertex to one of its neighbors, chosen uniformly at random. Tocover time is the first time when the particle has visited all the vertices in the graph starting from a given vertex. In this paper, we present upper and lower bounds that relate the expected cover time for a graph to the eigenvalues of the Markov chain that describes the random walk above. An interesting consequence is that regular expander graphs have expected cover time (n logn).This research was done while this author was a postdoctoral fellow in the Department of Computer Science, Princeton University, and it was supported in part by DNR grant N00014-87-K-0467.     

Triterpene glycosides of Gypsophila patrinii III. The structure of philoside B

Summary The structure of philoside B — a gypsogenin nonaoside isolated from the roots ofGypsophila patrinii — has been established.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan'Branch, Academy of Sciences of the USSR. Correspondence Institute of Soviet Commerce. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 603–607, September–October, 1974.     

Changing selectivity of DNA oxidation from deoxyribose to Guanine by ligand design and a new binuclear copper complex

A dinuclear copper complex [CuII2(PD'O)(H2O)2]3+ (1) (where PD'OH is a pyridylalkylamine containing binucleating ligand) promotes guanine oxidation in single-stranded DNA in the presence of 3-mercaptopropionic acid and dioxygen. This reaction is detected after subsequent piperidine treatment. Little spontaneous strand scission indicative of deoxyribose oxidation is observed in contrast to the results known for other copper complexes. Chemical characterization and nanospray ionization mass spectrometry analysis of oligodeoxynucleotides treated with 1 suggest conversion of guanine residues to their 2,6-diamino-5-formamidino-4-hydroxypyrimidine (+18 amu) and possibly 5,8-dihydroxy-7,8-dihydroguanine (+34 amu) derivatives. The selectivity toward nucleobase rather than deoxyribose oxidation is discussed in terms of the specific nature of the dicopper (hydro)peroxo species formed with the PD'OH ligand versus the intermediates formed in the presence of other binucleating ligands.     

Non-self mappings in modular spaces and common fixed point theorems

The aim of this paper, is to introduce the convex structure (specially, Takahashi convex structure) on modular spaces. Moreover, we are interested in proving some common fixed point theorems for non-self mappings in modular space.