Minoru Imoto

Polymerization by Carbenoids, Carbenes, and Nitrenes

Abstract Carbenes are divalent carbons, as shown by :CR2, and have two electron spin states distinguished by a singlet state (S) and a triplet state (T). One of the best methods to generate a carbene is through the decomposition of a diazo compound by irradiation or by heating, especially in the presence of a solvent or of a catalyst:

Polymeric Phospholipid Analogs. XV. Polyacrylamides Containing Phosphatidyl Cholines

Abstract p-Acryloylaminophenyl-2-(trimethylammonium)ethyl phosphate, p-methacryloylaminophenyl-2- (trimethylammonium)ethyl phosphate, and p-methacryloylbenzoylaminophenyl-2-(trimethylammonium)ethyl phosphate were prepared, characterized, and polymerized with 2,2′-azobisisobutyronitrile (AIBN). The properties of the resultant polymers are described.

Polymeric Phospholipid Analogs. XXIV. Polymeric Phospholipid Analogs with Uridine Units

Abstract Since phospholipids are of considerable interest as essential components of biological membranes [1, 2], it has seemed promising to investigate the behavior of polymeric phospholipid analogs. For over 10 years, a large part of our efforts has been to prepare polymers containing phosphatidylethanolamine [3, 4] or choline [5–7] analogs in the side chains and phosphatidylcholine analogs [8–10] in the main chains. A part of this programs was to synthesize polymeric phospholipid analogs containing nucleosides [11, 12], e.g., uridine, as in the work reported here.

Polymeric Phospholipid Analogs. XXII. A Synthetic Polypeptide with Phospholipid Analogs

Abstract Within the past 15 years, a considerable amount of our effort has been directed toward the syntheses and properties of the polymers containing phosphatidylethanolamine [1, 2] and choline [3–5] analogs in the side chains and phosphatidylcholine analogs in the main chains [6]. On the other hand, it is well known that biological membranes are formed of lipids and proteins composed of polypeptide chains [7]. Therefore, it seemed to be of great interest to prepare a synthetic polypeptide containing phospholipid analogs in the side chains.

Studies of the Mechanism of Mastication of Rubber. V. The Viscosity Lowering of Rubber Solutions by Phenyl Disulfide Derivatives

Abstract Nine derivatives of phenyl disulfide having substituents in the o- or p-position, were synthesized, and the lowering of the viscosity of toluene solutions of rubber by means of these deriv...

Syntheses of Polymers and Oligomers Having Adenine Derivatives

Abstract 9-(2′,3′-Dihydroxyethyl)-8-bromoadenine was synthesized by the reaction of 9-(2′,3′-dihydroxyethyl)-adenine with bromine. The reaction of 9-(2′,3′-dihydroxyethyl)-8-bromoadenine with phosphorus oxychloride in trimethyl phosphate produced 9-(2′,3′-dihydroxypropyl)-8-bromoadenine-3′-phosphate. The condensation polymerization of 9-(2′,3′-dihydroxypropyI)-8-bromoadenine-3′-phosphate was conducted in refluxing dimethylformamide-water (9:1) using dicyclohexylcarbodiimide as a dehydrating agent. The oligomer obtained is soluble in water and has a molecular weight of more than 1000 according to gel-filtration measurement. This oligomer showed hypochromicity of 3°, with denatured yeast RNA. The condensation polymerization of 9(2′,3′-dihydroxypropyl)-8-bromoadenine-3′ -phosphate was also carried out using imidazole or a triethylamine-hydrochloric acid system.

Vinyl Polymerization. 254.∗ Polymerization of Methyl Methacrylate by the System Cellulose-Water-Carbon Tetrachloride

Abstract Radical polymerization of methyl methacrylate initiated by the system cellulose-water-carbon tetrachloride was kinetically studied. Results obtained are: 1) The amounts of water, carbon tetrachloride, and cellulose affected the conversion. Michaelis-Mentens equation was applied to the relationship between the rate of polymerization and the amount of MMA. 2) Other methacrylates and acrylates were also polymerized by this system. 3) When methanol or ethanol was used instead of water, some weak polymerization activity was observed. 4) Initiating ability depended on the kind of cellulose used. 5) The activity of cellulose was not changed by washing with boiling water or by solvent extraction. 6) Polymerization was inhibited by the presence of air. 7) Heating in the presence of water and carbon tetrachloride markedly decreased the activity of the cellulose.

Vinyl Polymerization. 259. Polymerization of Methyl Methacrylate Initiated by p-Methoxy-p′-cyanodiphenyldiazomethane

Abstract A study of the polymerization of methyl methacrylate (MMA) in benzene initiated by p-methoxy-p′-cyanodiphenyldiazomethane (MCD) was made. The initial rate of the polymerization, Rp, followed the equation: Rp = k[MCD]Oe0.56[MMA]0.95 The rate for decomposition of MCD was measured in benzene in the range 50 to 80°C, and the following rate equation was obtained: kd[sec−1] = 7.42 × 1012 exp (-25.7 kcal/RT) On the basis of the results, the initiation mechanism of the polymerization by MCD is discussed.

Vinyl Polymerization. CLXXXV. Polymerization of Methyl Methacrylate Initiated with Benzoic Anhydride and Dimethylaniline N-Oxide. Effects of Solvent and the Substituent of the Initiator

Abstract Studies on the rate of the reaction of substituted dimethylaniline N-oxide (DMAO) with substituted benzoic anhydride (Bz2O) and the rate of polymerization of methyl methacrylate (MMA) with their systems were made. The solvent effects on the rate of the reaction of DMAO with Bz2O and on the polymerization of MMA with the system were also studied.

Vinyl Polymerization. CLXXII. Polymerization of Methyl Methacrylate Initiated by Nickel Peroxide

Abstract When nickel peroxide was used as an initiator of the polymerization of methyl methacrylate, it was found that the radical polymerization proceeded easier than styrene under similar conditions, and that the polymers obtained at low temperatures showed somewhat increased syndiotactic sequence as compared with ordinary radical polymers. From the NMR determinations of the polymers resulted by nickel peroxide at various temperatures, the Bovey-Tiers relationship, that is, that the probabilities of formation of isotactic, syndiotactic, and heterotactic triads of monomer unit among the polymer chain are controlled by a single parameter of the probability of isotactic addition of monomer in the propagation step was confirmed in this case. Similarly, the ratio ki/ks in rate constants for isotactic and syndiotactic additions in the polymerization by nickel peroxide in bulk was expressed by the following equation: In this equation, the difference in activation energy and entropy were somewhat larger than th...