Luteochrome; spektroskopische,chiroptische und chromatographische Eigenschaften

Two Optically Active Luteochromes: Preparation, Spectra and Chiroptical and Chromatographic Properties Selective rearrangement of (5R,6S,5′ R,6′S)-5,6:5′, 6′ -diepoxy-5,6,5′, 6′ -tetrahydro- β,β -carotene with the aid ofan ethereal solution of malonic acid leads to the mixture of the C(8′)-epimeric luteochromes. HPLC separation gave the pure isomers. This is the first report on th preparation of optically active luteochromes.     

Darstellung und Eigenschaften von Chlorozinksäuren

Contributions to the Chemistry of Hydrazine and its Derivatives. 53. Synthesis of P-, As-, and Sb-substituted Hydrazines by Addition of P? H, As? H, and Sb? H Groups to N?N Double Bonds Addition of diphenylphosphinous acid, diphenylthiophosphinous acid, methyl hydrogen phenylphosphonite, diethyl hydrogen phosphite, diphenylphosphane, dibutylphosphane, diphenylarsane, diethylarsane, and diphenylstibane to the N?N double bond of diethyl azodicarboxylate, dimethyl azodicarboxylate, ethyl phenylazocarboxylate, and azobenzene yields the P-, As-, and Sb- substituted hydrazines 1–23 . The spectroscopic data agree with the structural formulae. The course of the reactions suggests a polar reaction mechanism except in the case of the synthesis of 15 , which probably proceeds via radical intermediates. The azo systems employed show a distinct graduation in their ability to add to the element-hydrogen groups used.     

Dihydroxytrimethylstiboran – einige Eigenschaften und Struktur

Dihydroxytrimethylstiborane – Properties and Structure (CH₃)₃Sb(OH)₂ · H₂O ( 1 ) is prepared by reaction of (CH₃)₃SbCl₂ and NaOH. 1 reacts with CO₂ to yield [(CH₃)₃SbOH]₂CO₃ · 2 H₂O ( 2 ). Thermogravimetric investigations and mass spectra show that 1 and 2 decompose at low temperature and low pressure to H₂O, CO₂ and (CH₃)₃SbO. The crystal and molecular structures of 1 and 2 are determined. 1 crystallizes orthorhombic (Pbca) with a = 1185.2, b = 1069.6, c = 1207.6 pm and Z = 8. 2 crystallizes in the acentric monoclinic space group Cc with a = 657.3, b = 1168.5, c = 2048.2 pm, β = 95,33° and Z = 4. The infrared spectra are discussed with regard to the hydrogen bonding.     

Darstellung und Eigenschaften der Imidodiphosphorsäureamide

Preparation and Properties of Imidodiphosphoric Acid Amides Trichlorophosphazene phosphoryldichloride, Cl₃P?N? P(O)Cl₂, reacts with the stoichiometric amount of anhydrous formic acid resulting the tetrachloride of the imidodiphosphoric acid, Cl₂(O)P? NH? P(O)Cl₂. This tetrachloride yields with diazomethane the N-methyl compound, Cl₂(O)P? N(CH₃)? P(O)Cl₂. The tetramide of the imidodiphosphoric acid and its octalkyl derivatives are obtained by reaction of the tetrachloride with ammonia, dimethylamine, and diethylamine, respectively.     

TiOBr; Darstellung,Eigenschaften und Struktur*

TiOBr was prepared by reaction of Ti with TiO₂ and Br₂. The compound forms fiat reddish-brown needles and shows a temperature independent weak paramagnetism. It crystallises in the orthorhombic system (Pmmn; a = 3.787, b = 3.487, c = 8.529 Å) with the FeOCl type of structure. The interatomic distances are Ti?O = 1.952; 2.245 Å (2X) and Ti?Br = 2.544 Å (2X).