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1Author    H. Parlar, R. Baumann, M. BahadirRequires cookie*
 Title    Triplett-sensibilisierte Isomerisierung des Insektizids Thiodan Triplet Sensibilized Isomers of the Insecticide Thiodane  
 Abstract    The photoisomerization reactions of cyclodiene insecticide Thiodane were investigated in dif-ferent solvent systems, with wavelengths above 290 nm. The results show that /S-isomere (2) can be converted in the presence of acetone into the a-isomere (1). Photokinetic experiments give sufficient information on the character of the excited state of these compounds. 
  Reference    Z. Naturforsch. 37b, 260—263 (1982); eingegangen am 26. Oktober 1981 
  Published    1982 
  Keywords    Thiodane, Photochemical Reactions, Isomerization 
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 TEI-XML for    default:Reihe_B/37/ZNB-1982-37b-0260_n.pdf 
 Identifier    ZNB-1982-37b-0260_n 
 Volume    37 
2Author    Y. Ukih, Aru Sato, T. O. Shinobu, H. Oshi, T. Etsuji Iida, Chifuyu Ogino, B. Eate Nicolaus, W. Akabayashi, P. E. Te, R. BögerRequires cookie*
 Title    Isomerization and Peroxidizing Phytotoxicity of Thiadiazolidine Herbicides  
 Abstract    Certain 5-(arylimino)-3,4-tetramethylene-l,3,4-thiadiazolidin-2-ones (thiadiazolidines) are peroxidizing bleaching herbicides which interrupt chlorophyll biosynthesis, inhibit the activity of protoporphyrinogen oxidase, lead to accumulation of protoporphyrin IX, and induce ethane formation in the light. The same effects are caused by their isomers, the 4-aryl-l,2-tetramethylene-l,2,4-triazolidin-3-one-5-thiones (triazolidines). Couples of thia­ diazolidines and corresponding triazolidine isomers were synthesized. Thiadiazolidines with a 4-bromophenylimino, 4-chlorophenylimino, 4-chloro-2-methylphenylimino, 4-chloro-2-fluorophenylimino, 4-chloro-2-fluoro-5-propargyloxyphenylimino and 4-chloro-2-fluoro-5-isopropoxyphenylimino moiety were converted to the corresponding triazolidines both with Echinochloa seedlings or a spinach homogenate present, depending on the 5-arylimino moiety. The 5-[4-(chlorobenzyloxy)phenylimino]-3,4-tetramethylene-l,3,4-thiadiazolidin-2-one analogue did not convert to the corresponding triazolidine under both conditions. Thiadiazolidines as well as triazolidines having a 4-chloro-2-fluoro-5-methoxycarbonyl-methylthiophenyl moiety were converted to an unidentified compound whose structure is assumed to be 4-(4-chloro-2-fluoro-5-carboxymethylthiophenyl)-l,2-tetramethylene-l,2,4-triazolidin-3-one-5-thione. Apparently, the general conversion mechanism is caused by enzymatic hydrolysis of thiadiazolidines to an unstable intermediate which rapidly and spon­ taneously changes to the corresponding triazolidine isomer. 
  Reference    Z. Naturforsch. 49c, 49 (1994); received November 121993 
  Published    1994 
  Keywords    Proherbicide, Isomerization, Triazolidinonethiones, Thiadiazolidinones, Echinochloa 
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 TEI-XML for    default:Reihe_C/49/ZNC-1994-49c-0049.pdf 
 Identifier    ZNC-1994-49c-0049 
 Volume    49 
3Author    J. R., D. B., F. K.Requires cookie*
 Title    High Pressure Reactions, IX 1 Isomerizations at High Pressures  
 Abstract    Cyclooctatetraene dimerises at high pres­ sure (12 Kbar, 20 °C) to the isomers 2 and 3. At 120 °C compound 2 isomerises quanti­ tatively to compound 3. The conversion rate of Hexamethyldewarbenzene to Hexamethyl-benzene at high pressures depends on kind of solvent, whereas the influence of tempera­ ture is small in the range between 2 0 ° and ' 80 °C. 
  Reference    (Z. Naturforsch. 30b, 290 [1975]; eingegangen am 17. Oktober 1974) 
  Published    1975 
  Keywords    High Pressure, Cyclooctatetraene, Dimerisation, Hexamethyldewarbenzene, Isomerization 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0290_n.pdf 
 Identifier    ZNB-1975-30b-0290_n 
 Volume    30 
4Author    Kerstin Dippel, Uwe KlingebielRequires cookie*
 Title    Kontraktionsreaktionen lithiierter Cyclotetrasilazane zu Cyclotri-und Cyclodisilazanen C ontraction Reactions of Lithiated Cyclotetrasilazanes Yielding Cyclotri-and Cyclodisilazanes  
 Abstract    The lithium derivate o f the octamethylcyclotetrasilazane 1 reacts with fluorosilanes with substitution (2) or substitution and contraction to give cyclotrisilazanes (3 —6). Lithiated 6 again reacts with substitution (7, 11, 12) or substitution and isomerization to give l,3 -(S i-N -S i) substituted cyclodisilazanes (8 , 13). Starting with the dilithiated eight mem-bered ring (14) the reactions with fluorosilanes lead to the formation o f the unsymmetrically l-(S i)-3 -(S i-N -S i-N -S i)-s u b s titu te d four mem bered rings (9, 10). The isomerization o f the lithium salts depends on thermal, thermodynamic and kinetic effects. 
  Reference    Z. Naturforsch. 45b, 1147—1154 (1990); eingegangen am 26. Januar 1990 
  Published    1990 
  Keywords    Cyclotetrasilazane, Lithium Salts, Isomerization, Cyclodisilazanes, Cyclotrisilazanes 
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 TEI-XML for    default:Reihe_B/45/ZNB-1990-45b-1147.pdf 
 Identifier    ZNB-1990-45b-1147 
 Volume    45