2-Nitromethyl-2-trichloromethyl-1,3-benzodioxoles and 2-nitromethyl-2-trichloromethyl-1,3-benzoxazolines: Synthesis and structure

A reaction of 1-bromo-3,3,3-trichloro-1-nitropropene with pyrocatechol, o-aminophenol, and their substituted derivatives led to 2-nitromethyl-2-trichloromethyl-1,3-benzodioxoles and 2-nitromethyl-2-trichloromethyl-1,3-benzoxazolines. The structure of the compounds synthesized was established by IR, ¹H and ¹³C NMR spectroscopy with HMQC and HMBC ¹H—¹³C experiments, and X-ray diffraction analysis.     

Synthesis of Diaminophosphonium Salts [Ph2(ArNH)2P]+Br− (Ar = o-MeC6H4, p-MeC6H4, p-Pr i C6H4, p-EtO2CC6H4, p-MeOC6H4)

The behavior of different anilines H₂NC₆H₄R (R = o-Me, p-Me, o-, m- and p? ⁱ Pr, p-OMe, p-CO₂Et) and 2,6-Me₂C₆H₃NH₂ towards trihalophosphoranes was studied. 2,6-Me₂C₆H₃NH₂ failed to form the diaminophosphonium salt [Ph₂PNH(2,6-Me₂C₆H₃)₂]Br, and the aminophosphine oxide Ph₂(2,6-Me₂C₆H₃NH)PO was the only isolated product. Both o- and p-toluidine gave the corresponding diaminophosphonium salts; however in the case of o-toluidine, the yield was low and a mixture with the respective aminophosphine oxide was observed. Anilines containing methoxy and ethoxycarbonyl groups in para-position form the diaminophosphonium salts in reasonable yields.     

Two isostructural carboranes: 3‐phenyl‐1,2‐dicarba‐closo‐dodecaborane(12) and 1‐phenyl‐1,7‐dicarba‐closo‐dodecaborane(12)

Two phenyl‐substituted carboranes, 3‐phenyl‐1,2‐dicarba‐closo‐dodecaborane(12), C₈H₁₆B₁₀, (I), and 1‐phenyl‐1,7‐dicarba‐closo‐dodecaborane(12), C₈H₁₆B₁₀, (II), were found to be isostructural. Comparison of the bond angles at the ipso‐C atoms of the phenyl substituent for (I) and (II) [117.71 (3) and 118.45 (10)°, respectively] indicates that electron donation of the carborane cage for B‐ and C‐substituted carboranes is different.     

Synthesis and structural features of tetranuclear rhodium complexes of amidophosphito- and phosphitocavitands

Interactions of acetylacetonatodicarbonylrhodium(1) with amidophosphito- and phosphitocavitands were studied. First representatives of tetranuclear cavity complexes of rhodium(1) were obtained. It was established by NMR spectroscopy and X-ray diffraction studies that the chemically identical phosphorhodium centers in these complexes differ in the spatial arrangement, and the system as a whole becomes unsymmetrical. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1852–1858, September, 1998.     

SelectiveC-mono- andC,C-dialkylation of thiophosphorylacetonitriles

Alkylation of thiophosphorylacetonitriles under phase transfer catalysis conditions in the 50% NaOH/CH₂Cl₂ system proceeds as monoalkylation, whereas alkylation in MeCN with the use of solid KOH as a base gives a disubstituted product. The order in which the reagents were added as well as dilution of the reaction mixture affected substantially the yields of the target compounds. X-ray diffraction analysis of a single crystal of dibutyl(diphenylthiophosphoryl)acetonitrile was carried out. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 990–996, May, 1998.     

Eine Mikrobestimmung von Kobalt und Kupier

Ohne Zusammenfassung     

Interwell excitons in GaAs multiple quantum wells and superlattices

Il Nuovo Cimento D - The optical properties of multiple quantum wells in the transition from isolated wells to a superlattice are investigated theoretically and experimentally. For superlattices...     

Synthesis of chiral glycolurils from (<Emphasis Type="Italic">S</Emphasis>)-(+)- and (<Emphasis Type="Italic">R</Emphasis>)-(-)-1-<Emphasis Type="Italic">sec</Emphasis>-butyl-3-methylurea

Chiral dialkyl- and tetraalkylglycolurils have been obtained using chiral (S)-(+)- and (R)-(-)-1-sec-butyl-3-methylurea as starting materials. The diastereomer (S)-(+)-2,6-di-sec-butyl-4,8-dimethyl-2,4,6,8-tetraazabicyclo[3.3.0]-octane-3,7-dione was separated into stereoisomers, for the higher melting of which the absolute configuration was determined as (S,S,S,S) by X-ray structural analysis.     

Formation of unsymmetrical 1,4-dithiins from fused 1,2,3,4,5-pentathiepins: synthesis,structural, and computational study

Pentathiepinopyrroles reacted with methyl propiolate and triphenylphosphine to give regioselectively dithiinopyrroles in agreement with the electron distribution in the proposed reaction intermediate. Thieno[2,3-f][1,2,3,4,5]pentathiepin when treated with methyl propiolate and triphenylphosphine gave a pair of regioisomers where the higher yielding regioisomer contained the same mode of junction as in the case of pentathiepinopyrroles. X-ray crystal structures are provided for the thieno[2,3-b][1,4]dithiine carboxylate isomers. Quantum-chemical calculations B3LYP/6-31G(d) and B3LYP/6-311⁺⁺G(d,p) have been carried out for better understanding of the reaction mechanisms; the index of synchronism of the S_h addition and the index of a relative difference in bond orders in transition states are in good agreement with the formation of the regioisomers by the reaction of unsymmetrical pentathiepins with alkynes containing one electron-withdrawing group.