Structure investigation of new condensation products of 1,2,3,3-tetramethylindolenium with metoxy-substituted diformylphenols

To assess the effectiveness of bus fleet technical maintenance, service cost evaluation should be organized. This cost analysis is essential for effective management at automobile operating company. The article describes the bus transport position in Moscow transport economy. The importance of technical maintenance in a bus transport system is defined. Special attention is given to the cost structure investigation.

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An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19912917 ◽

1991 ◽

Vol 56 (12) ◽

pp. 2917-2935 ◽

Cited By ~ 1

Author(s):

Eva Klinotová ◽

Václav Křeček ◽

Jiří Klinot ◽

Miloš Buděšínský ◽

Jaroslav Podlaha ◽

...

Keyword(s):

Acetic Acid ◽

Nmr Spectroscopy ◽

Acetic Anhydride ◽

Spectral Methods ◽

X Ray Diffraction ◽

X Ray ◽

Mild Conditions ◽

Condensation Products ◽

Unsaturated Lactones ◽

C Nmr

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

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Voltammetric Studies of Some Novel Fe(III) Complexes with Quadridentate Ligands. The Axial Ligand-Exchange Reactions in DMF and DMSO

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19951140 ◽

1995 ◽

Vol 60 (7) ◽

pp. 1140-1157 ◽

Cited By ~ 1

Author(s):

Ljiljana S. Jovanovic ◽

Luka J. Bjelica

Keyword(s):

Oxidation State ◽

Chemical Reactions ◽

Ligand Exchange ◽

Kinetic Data ◽

Central Atom ◽

Axial Ligand ◽

Exchange Reactions ◽

Ligand Effect ◽

Condensation Products ◽

Voltammetric Studies

The electrochemistry of four novel Fe(III) complexes of the type [Fe(L)Cl], involving quadridentate ligands based on the condensation products of benzoylacetone-S-methylisothiosemicarbazone with salicylaldehyde, 5-chlorosalicylaldehyde, 3,5-dichlorosalicylaldehyde or 5-nitrosalicylaldehyde, was studied in DMF and DMSO at a GC electrode. All complexes undergo a two-step one-electron reductions, usually complicated by chemical reactions. In solutions containing Cl-, the ligand-exchange reactions Cl--DMF and Cl--DMSO take place. Stability of the chloride-containing complexes was discussed in terms of the coordinated ligand effect, oxidation state of the central atom and, in particular, of the donor effect of the solvent. Some relevant kinetic data were calculated.

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