Photochemical reactions of pyrimidine and purine bases are reviewed. These include photodimerization, photohydration, and photoadditions of pyrimidine bases. Photoadditions of nucleic acid with a wide variety of compounds are also described. In particular, photoinduced addition of amino acids to nucleic acid constituents are discussed in connection with the photoinduced cross-linking of nucleic acids to proteins.
Natural dehydroamino acids and dehydropeptides are reviewed with respect to the isolation, the structure, and the biological activities. Synthetic aspects on dehydropeptides are also reviewed, and finally, the structure and function of AM-toxins, phytotoxic cyclotetradepsipeptides containing a dehydroalanine, are discussed through synthetic studies.
The recent trends of fluoro-organic specialty chemical industry were reviewed. The market, general information and application of water and oil repellent, surfactans, lubricants biomedical chemicals were included.
The oxidizing action of the new oxidizing system using molten potassium hydroxide-manganese dioxide-air was studied. In the reaction in nitrogen, the mean oxidation number of the recovered manganese was 2.90, and the yield of terephthalic acid (1) was 33 mol %. The result is explainable by the decrease of the oxidation number of manganese from 4 mostly to 3 and partly to 2. In the reactions in air and oxygen, the oxidation numbers of the recovered manganese were 3.68 and 3.73, and the yields of (1) were 87 and 76 mol %. In these cases the results are not explainable only by the decrease of the oxidation state of manganese. Further, it was found that potassium manganate (MnVI) is partly formed in molten KOH-MnO2 in air at the reaction temperature of about 250°C. From these facts, it has become clear that the manganese in molten KOH-MnO2 in air may function as oxidizing agents with the oxidation number between 6 and 2, and may behave as a catalyst catching oxygen from the atmosphere and giving it to organic compound.
The oxidation of p-toluic acid in molten potassium hydroxide was studied with various metal oxides under an normal pressure of air. It was found that p-toluic acid is oxidized to terephthalic acid with silver (I) oxide, vanadium (V) oxide, iron (III) oxide, mercury (II) oxide, molybdenum (VI) oxide, cobalt (III) oxide, thallium (III) oxide, copper (II) oxide, copper (I) oxide and potassium chromate. The oxidation is mainly performed with the decrease of the oxidation number of the metals in the potassium salts of metallic acids which are formed from metal oxides dissolving in molten potassium hydroxide. A higher yield of terephthalic acid was obtained by the use of the metal compound in higher oxidation state. In general, terephthalic acid was formed in higher yield with a metal compound of smaller standard oxidation reduction potential (EOB) in alkaline medium such as MnO42-→MnO2, Ag2O→Ag and PbO2→PbO. From this general rule one can expect what substance is effective in this oxidation process. As an example, oxygen (EOB = -0.401 volt) can be used under an initial pressure of 30 kg/cm2 to give terephthalic acid in 83 mol % yield from p-toluic acid. Thus it can be used as a new oxidation method of organic compounds.
Partial hydrogenation of diphenylacetylenes to stilbenes was effected with high selectivity by hydrogen transfer from N-benzylaniline in the presence of palladium-charcoal. 1, 3-, 1, 5-Cyclooctadiene, and trans, trans, trans-1, 5, 9-cyclododecatriene were hydrogenated selectively to the corresponding monoenes.
The Beckmann fission of 2-acetoxycyclopentanone oxime (1e) and 2-benzoyloxycyclopentanone oxime (1f) with phosphorus pentachloride at 0°C gave5-acetoxy-5-chlorovaleronitrile (3e) and 5-benzoyloxy-5-chlorovaleronitrile (3f) in 56 %and 71 % yields, respectively. The hydrolysis of (3e) gave 4-cyanobutanal (2) and 5-acetoxy-cis-4-pentenenitrile (5). The methanolysis of (3e) gave (2) and its dimethyl acetal (6). These reactions proceeded by the Sn1 mechanism. The reaction of (3e) with several nucleophiles were carried out in anhydrous and aqueous solvents. Sodium cyanide and silver nitrite reacted with (3e) in anhydrous tetrahydrofuran or diethyl ether to give 2- acetoxyadiponitrile (7) (99 ro) and 1-acetoxy-4-cyanobutyl nitrite (9) (59 %), respectively. Sodium azide and sodium acetate hardly reacted with the chlorine of (3e) in anhydrous acetone, whereas 5-acetoxy-5-azidovaleronitrile (10) and 5, 5-diacetoxyvaleronitrile (11) were obtained in about 20 % yield in aqueous acetone.