Precise synthesis of porphyrin array scaffolding polyisocyanides

Aryl isocyanides bearing free‐base and metallo‐porphyrins were prepared and polymerized with a Pd–Pt μ‐ethynediyl complex as the initiator to give polymers with narrow polydispersity indices. The molecular weights of the resulting polymers were precisely controlled by the initial feed ratio of the porphyrin monomer to the initiator. The UV–VIS spectra suggested that the porphyrin pendants are regularly arranged to form stacked columns. Metallo‐porphyrin polymers were also prepared by reacting free‐base porphyrin polymers with metal salts. The successive reactions of free‐base and zinc‐porphyrin monomers resulted in the formation of diblock polymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 585–595, 2006     

High-speed counter-current chromatography of apple procyanidins

Apple procyanidins were separated by high-speed counter-current chromatography using a type-J multilayer coil planet centrifuge. Several two-phase solvent systems with a wide range of hydrophobicities from a non-polar hexane system to polar n-butanol systems were evaluated their performance in terms of the partition coefficient and the retention of the phase. The best separation of procyanidins B and C was achieved with a two-phase solvent system composed of n-butanol-methyl tert.-butyl ether-acetonitrile-0.1% trifluoroacetic acid (2:4:3:8) using the lower phase as a mobile at a flow-rate of 1.0 ml/min.     

INVESTIGATIONS ON THE MECHANISM OF CHLORPROMAZINE PHOTOTOXICITY: EFFECTS ON LYSOSOMES OF CULTURED HUMAN FIBROBLASTS

Abstract The effect of chlorpromazine (CPZ) and UVA on lysosomes of cultured normal human fibroblasts has been investigated. Acid phosphatase (ACPase) activity in 12 000 g pellet of cells treated with CPZ (10 μg/m l ) and UVA (6 × 10⁴ J/m²) was found to be decreased as compared with non-treated, CPZ or UVA treated control cells. This decrease, however, was not accompanied by a concomitant increase in ACPase activity in the 12 000 g supernatant. The addition of Triton X-100 to cells pretreated with CPZ + UVA resulted in only a moderate increase in ACPase activity of the 12 000 g supernatant. ACPase activity of the cells incubated in media containing preirradiated CPZ was also found to he decreased. These results indicate that CPZ + UVA directly inactivate lysosomal enzymes, possibly without affecting the membrane.     

Intramolecular Nucleophilic Acyl Substitution Reaction of 3,4-Alkadienyl Carbonates Mediated by Ti(O-i-Pr)(4)/2 i-PrMgCl Reagent. Efficient Synthesis of Optically Active beta,gamma-Unsaturated Esters with an alpha-Substituent

Treatment of 3,4-alkadienyl carbonates 2a-i with a low-valent titanium reagent diisopropoxy(eta(2)-propene)titanium (1), readily generated by the reaction of Ti(O-i-Pr)(4) with 2 i-PrMgCl, resulted in an intramolecular nucleophilic acyl substitution (INAS) reaction to afford vinyltitanium compounds 3 which, in turn, reacted with H(3)O(+), D(2)O, or iodine to give alpha-substituted beta,gamma-unsaturated esters 4 in good to excellent yields. The olefin moiety of the hydrolysis product 4 has (Z)-geometry mainly except for 4h. Starting from chiral 2f or 2g, the reaction proceeded stereospecifically to give optically active alpha-substituted beta,gamma-unsaturated ester 4f or 4g having (Z)-olefin geometry exclusively.     

THE ACTION SPECTRUM AND DOSE RESPONSE STUDIES OF UNSCHEDULED DNA SYNTHESIS IN NORMAL HUMAN FIBROBLASTS

Abstract— Excision repair of DNA damage by UV has been assessed in normal human fibroblasts in culture by measuring unscheduled DNA synthesis. Dose response experiments indicated that the same chromophore was involved in UV-induced damage and excision repair at three different wavelengths between 260 and 300 nm. Action spectra for unscheduled DNA synthesis were determined at wavelengths between 260 and 320 nm 30 min after irradiation using 2 doses of UV, 100 J m^-2and 10Jm^-2. Experiments at the lower dose were carried out because it appeared that repair was saturated with the higher dose at 260 and 280 nm. To explore this part of the spectrum further, experiments were performed with different doses at 260 and 280 nm and unscheduled DNA synthesis assessed 30 min and 24 h after irradiation. At 24 hr after irradiation a significantly greater amount of unscheduled DNA synthesis occurred at 280 nm. It is suggested, therefore, that both DNA and protein are concerned in the absorption of UV which leads to DNA damage and excision repair.     

An efficient synthesis of the orally-active GpIIb/IIIa antagonist FR184764

An efficient synthesis of the orally-active GpIIb/IIIa antagonist FR184764 was achieved. The key intermediate, an optically active ethynyl β-amino ester, was synthesized efficiently by utilizing a lipase catalyzed kinetic resolution step.     

Ti(II)-mediated domino cyclization of 2-functionalized 1-halo-2,n-enynes (n = 7, 8) to bicyclic compounds

The reaction of 2-functionalized 1-halo-2,n-enynes (n = 7 or 8) with a divalent titanium reagent, Ti(O-i-Pr)₄/2i-PrMgCl, proceeded in a domino fashion to afford bicyclic compounds in good yields.     

Rational Design for Cooperative Recognition of Specific Nucleobases Using β‐Cyclodextrin‐Modified DNAs and Fluorescent Ligands on DNA and RNA Scaffolds

We propose a binary fluorimetric method for DNA and RNA analysis by the combined use of two probes rationally designed to work cooperatively. One probe is an oligonucleotide (ODN) conjugate bearing a β‐cyclodextrin (β‐CyD). The other probe is a small reporter ligand, which comprises linked molecules of a nucleobase‐specific heterocycle and an environment‐sensitive fluorophore. The heterocycle of the reporter ligand recognizes a single nucleobase displayed in a gap on the target labeled with the conjugate and, at the same time, the fluorophore moiety forms a luminous inclusion complex with nearby β‐CyD. Three reporter ligands, MNDS (naphthyridine–dansyl linked ligand), MNDB (naphthyridine–DBD), and DPDB (pyridine–DBD), were used for DNA and RNA probing with 3′‐end or 5′‐end modified β‐CyD – ODN conjugates. For the DNA target, the β‐CyD tethered to the 3′‐end of the ODN facing into the gap interacted with the fluorophore sticking out into the major groove of the gap site ( MNDS and DPDB ). Meanwhile the β‐CyD on the 5′‐end of the ODN interacted with the fluorophore in the minor groove ( MNDB and DPDB ). The results obtained by this study could be a guideline for the design of binary DNA/RNA probe systems based on controlling the proximity of functional molecules.