Artificial photochemical nitrogen cycle to produce nitrogen and hydrogen from ammonia by platinized TiO2 and its application to a photofuel cell

Photochemical artificial nitrogen cycle was reported to produce dinitrogen and dihydrogen by photodecomposing ammonia with platinized TiO2, and its application to a photofuel cell with a nanoporous TiO2 film electrode, a new concept of a fuel cell to photochemically produce electricity and H2 from ammonia, was proposed.     

Remarkable effect of 2[small alpha]-modification on the VDR antagonistic activity of 1small alpha-hydroxyvitamin D3-26,23-lactones

Novel 2[small alpha]-methyl-, 2[small alpha]-(3-hydroxypropyl)- and 2[small alpha]-(3-hydroxypropoxy)-substituted 25-dehydro-1[small alpha]-hydroxyvitamin D-26,23-lactone derivatives were efficiently synthesized Reformatsky type allylation and palladium-catalyzed alkenylative cyclization processes, and their biological activities were evaluated. Introducing functional groups into the 2[small alpha]-position of the vitamin D-26,23-lactones resulted in remarkable enhancement of their antagonistic activity on vitamin D receptor (VDR).     

Synthesis of Immunosuppressive Neoglycoproteins: Bovine Serum Albumin Coupled with 8-(Hydrazino-Carbonyl)Octyl 4- Or 6-O-α-D-Mannopyranosyl-α-D-Mannopyranoside

Abstract

Recombinant cytokines generated by bacteria, especially E. coli, are nonglycosylated. To investigate the effects of carbohydrates on their activities, we attempted to develop new cytokines by introduction of carbohydrates. As a model we synthesized neoglycoproteins in which potential immunoregulatory carbohydrates were coupled to bovine serum albumin(BSA). Mannose dimers with C9 spacer, Manα1-6Man, which is reported to be immunosuppressive, and a reference substance Manα1-4Man were synthesized as follows. Benzylidenation of 8-(methoxycarbonyl)octyl α-D-mannopyranoside (10), followed by acetylation and cleavage of the benzylidene acetal, gave a glycosyl acceptor (13) with a free hydroxyl group in the C-4 position. Glycosylation of 13 with acetobromomannose (8), followed by debenzylation, deacetylation, and hydrazidation, gave 8-(hydrazinocarbonyl)octyl 4-O-α-D-mannopyranosyl-α-D-mannopyranoside (1). Total yield of 1 from 10 was 25.1%. Tritylation of 10, followed by acetylation and detritylation, gave a glycosyl acceptor (18) with a free hydroxyl group in the C-6 position. Analogous condensation of 18 with 8, followed by deacetylation and hydrazidation, gave 8-(hydrazinocarbonyl)octyl 6-O-α-D-mannopyranosyl-α-D-mannopyranoside (2). Total yield of 2 from 10 was 22.9%. These mannose dimers were coupled to BSA by the acyl azide method. Using the antibodies against the mannose dimers, an enzyme linked immunosorbent assay (ELISA) was established to measure the small amount of mannose dimers coupled to proteins. These two neoglycoproteins appeared to inhibit the antigen-specific human T cell proliferation over 100 fold more efficiently than free mannose dimers.     

Thermal hysteresis and thickness dependence of the molecular orientation of poly(di-n-hexylsilane) in the film state

Molecular orientation of poly(di-n-hexylsilane) adsorbed on poly(vinyl alcohol) film has been studied by making use of the stretching technique. Dichroic ratio, Rd, strongly depended on the thickness of poly(di-n-hexylsilane) thin film and the highest value ca. 19 was observed at the film thickness of 110 +/- 30 nm. The thermal hysteresis of the molecular orientation was observed in the heating-cooling cycles. By studying the fluorescence spectrum it was confirmed that a portion of the poly(di-n-hexylsilane) molecules were in transoid conformation even at 320 K, although most of poly(di-n-hexylsilane) molecules were in disordered conformation (conformation D). This poly(di-n-hexylsilane) in transoid conformation is formed in the stretching process and may play a role of crystallization nucleus to induce the whole orientation of the poly(di-n-hexylsilane) in the film state.     

Palladium charcoal-catalyzed deprotection of O-allylphenols

Allyl aryl ethers can be easily cleaved by the use of 10% Pd/C under mild and basic conditions. The present reaction would involve a SET process rather than a π-allyl-palladium complex. The scope and limitation of this new deprotective methodology is also described.     

Isolation and characterization of dinochrome A and B,anti-carcinogenic active carotenoids from the fresh Water red tide Peridinium bipes

Two epimeric carotenoids, named dinochromes A (2) and B (3), were isolated from the fresh water red tide Peridinium bipes, as anti-carcinogenic compounds. The stereostructure of dinochrome A and B were characterized to be (3S,5R,6R,3'S,5'R,8'R)- and (3S,5R,6R,3'S,5'R,8'S)-5',8'-epoxy-6,7-didehydro-5,6,5',8'-tetrahydro-beta,beta-carotene-3,5,3'-triol 3-O-acetate, respectively by (1)H- and (13)C-NMR, and circular dichroism (CD) data. Dinochromes A (2) and B (3) inhibit 12-O-tetradecanoyl phorbol 13-acetate (TPA)-stimulated (32)P-incorporation into the phosholipids of HeLa cells. Furthermore, dinochrome A was found to inhibit the proliferation of human malignant tumor cells, such as GOTO, OST and HeLa cells.     

BIPHASIC M DECAY OF HIGH pH DEHYDRATED PURPLE MEMBRANE STUDIED WITH FOURIER TRANSFORM INFRARED SPECTROSCOPY: A MODEL ACCOUNTING FOR FUNCTIONAL DIFFERENCES BETWEEN DIFFERENT M FORMS

Abstract— A purple membrane film treated with a pH 10 buffer and subsequently dehydrated exhibits an M intermediate that consists of two clearly separable fast-and slow-decaying forms at 275 K; 45% decays thermally within the first 10 min but most of the remaining is stable even after 25 min. Fourier transform infrared spectroscopy is applied to investigate differences in molecular structural changes accompanying thermal decay of the fast-decaying form and photochemical decay (M bacteriorhodopsin back photoreaction) of the slow-decaying form. When difference spectra are taken of the two decay transitions, small but highly reproducible differences are observed. These suggest differences in molecular structural changes accompanying the two decay transitionas. However, the high degree of similarity in the spectra also suggests that these forms of M are not in thermal equilibrium with other intermediates such as N. We propose a model to account for functional differences between two M forms.     

Synthesis of 2,3‐Diaryl‐3H‐pyrrolo[2,3‐c]pyridin‐3‐ol Derivatives by the Reaction of Aryl(3‐isocyanopyridin‐4‐yl)methanones with Aryl Grignard Reagents

The reaction of aryl(3‐isocyanopyridin‐4‐yl)methanones 1 , easily prepared from commercially available pyridin‐3‐amine, with aryl Grignard reagents gave, after aqueous workup, 2,3‐diaryl‐3H‐pyrrolo[2,3‐c]pyridin‐3‐ols 2 . These rather unstable alcohols were O‐acylated with Ac₂O in pyridine in the presence of a catalytic amount of 4‐(dimethylamino)pyridine (DMAP) to afford the corresponding 2,3‐diaryl‐3H‐pyrrolo[2,3‐c]pyridin‐3‐yl acetates 3 in relatively good yields.     

Selectivity and recovery performance of phosphate-selective molecularly imprinted polymer

A phosphate-selective molecularly imprinted polymer was prepared using 1-allyl-2-thiourea as a functional monomer, and the binding ability and selectivity of the polymer were evaluated. The imprinted polymer showed high binding ability to and selectivity for phosphate in aqueous media. The recoverability of phosphate from the imprinted polymer was also examined, and nearly 70% of highly concentrated phosphate could be recovered.