An efficient diastereoselective synthesis of 6-hydroxy-4a-[3,4-crowned(15-crown-5)phenyl]-trans-decahydroisoquinoline

A high diastereoselective synthesis of 6-hydroxy-4a-aryl-$\text{trans}$-decahydroisoquinoline derivatives was achieved by an application of N-acyliminium ion-induced polyene cyclization procedure.     

Reconsideration of the present value method

In investment decision-making, the net present value method is widely used as one of the best decision rules (techniques or criteria). At the same time, it is also used to evaluate decision alternatives for a long range period of time, in economics or even in control theory. Its theoretical validation as the best method for investment decision-making has been based on a basis such that the best technique (investment decision rule) will maximize shareholders' wealth which is measured by the present value of cash flows discounted at the opportunity cost of capital. Such a theoretical requirement as maximizing shareholders' wealth is very important for investment decision-makings. This requirement implies that an ordering relation of projects determined by the best investment rule must be order-isomorphic to that determined by the measure of shareholders' wealth. This order-isomorphism can be represented by necessary and sufficient conditions (or separate criteria). However, they are not suitable for comparing investment decision rules, because they are designed for selecting the best investment decision rule. At the same time, the other dominance of the net present value method over other investment rules is also found in its decision-theoretical aspects. Formulating the net present value method, internal rate of return method and simple sum method in an axiomatic fashion, the net present value method is compared with the other rules, and is shown to have enough clarity and simplicity in theory and practice.     

Chemical modification of butyl rubber. III. Butyl rubber with D-maltose derivative as pendant groups

A new type of amphiphilic elastomer was synthesized, which consisted of butyl rubber and a D-maltose derivative as a backbone and side groups, respectively. The synthesis was accomplished by the sequence of the three following reactions: (1) Hydroxyl groups of D-maltonolactone were protected by a trimethylsilyl group. (2) The resulting maltonolactone derivative was subjected to a reaction with chemically modified butyl rubber having pendant amino groups. (3) The protecting trimethylsilyl groups on the maltose residues were removed by treating with tetra-n-butylammonium fluoride. This new amphiphilic elastomer behaved as a thermoplastic elastomer and showed good mechanical properties. The saccharide seg-ments aggregated in the hydrophobic butyl rubber matrix to form a microphase-separated structure, as confirmed by differential scanning calorimetry, transmission electron mi-croscopy, small-angle x-ray scattering, and dynamic mechanical measurements. The ag-gregated saccharide domains are estimated to function both as crosslinking sites and rein-forcing fillers in the rubber matrix. © 1995 John Wiley & Sons, Inc.     

Synthesis of quinoxaline derivatives through condensation of 1,2-diaminobenzenes with β-keto sulfoxides

The reaction of o-phenylenediamine with α-methylsulfinylcyclohexanone and α-methylsulfinylcyclopentanone in the presence of acetic acid afforded 1,2,3,4-tetrahydrophenazine and 2,3-dihydro-1H-cyclopenta[b]-quinoxaline, respectively. 3,4-Diaminotoluene and 3,4-diaminochlorobenzene were reacted with α-methyl-sulfinylacetophenone to give a mixture of the corresponding 6- and 7-substituted 2-phenylquinoxaline. Condensation of 3,4-diaminomethoxybenzene with α-methylsulfinylacetophenone gave 7-methoxy-2-phenylacetophenone, whereas, the same reaction between 3,4-diaminonitrobenzene and α-methylsulfinylacetophenone yielded 6-nitro-2-phenylquinoxaline.     

TE-TM Mode Converter Using Optically Active Polymer

A novel TE-TM mode converter using optically active polymer: poly-1-menthylmethacrylate (PMtMA) was studied theoretically and experimentally. In a three-layered slab waveguide consisting of the PMtMA core layer on a fused quartz substrate, a low-loss TE₀-TM₀ mode conversion with an efficiency of 60 to 70% was easily obtained for the first time at a wavelength of 441.6 nm. The method to achieve a phase-matched operation of this polymer TE-TM mode converter was also discussed.     

A New Plastic Optical Fiber Sensor for Oxygen Based on Fluorescence Enhancement

A new method for the detection of low oxygen concentration is proposed here. The system is based on the principle of enhancement of fluorescence yield of tetraphenylporphine (TPP) dye at λ=656 nm when excited by He-Cd laser at λ =441 nm in the presence of oxygen. The sensor head was fabricated by cladding the ARTON fiber core with the poly-4-methy1-1-pentene polymer matrix doped with TPP. The experimental results obtained indicate a good enhancement in the fluorescence when the sensor head is exposed to oxygen. The response was found to be linear and stable in the range of (100 ppm-1%) with the resolution of 0.01%. The sensor response was characterized by studying its response for change in temperature and is discussed below.     

Photochromic and photomechanical ionene elastomer containing poly(tetrahydrofuran) segments and viologen units

Elastomeric polymer consisting of poly(oxytetramethylene) segments and viologen units (PTV) was synthesized by the reaction of dicationic living poly(tetrahydrofuran) with 4,4′-bipyridine at ?70°C. The chloride or bromide ion was introduced as the counter anion into the viologen groups of PTV by the treatment of the reaction mixture with aqueous sodium chloride or bromide, respectively. The solid film of PTV having chloride inon showed photochromism, i.e., color change by light irradiation, via photoreduction of the violegen groups. In contrast. PTV of bromide counter anion required a small amount of poly(N-vinyl-2-pyrrolidone) to undergo the photochromic reaction. The irradiation of light also affected the stress relaxation of the polymers, namely PTV showed photomechanical behavior. This phenomenon is considered to be induced by the decrease of total number of ionic charges of PTV by photo-reduction of the viologen groups followed by the change of a state of ionic clustering in the polymer matrix.