Titanium n

Owing to their particular interest two individual reactions will now be discussed separately. The reaction of methoxycarbonylhydrazine and 3-bromo-2,4-pentanedione affords, in addition to the expected pyrazole (608), a pyrazolium salt (609), the structure of which was established by X-ray crystallography (74TL1987). Aryldiazonium salts have been used instead of arylhydrazines in the synthesis of pyrazolines (610) and pyrazoles (611) (82JOC81). These compounds are formed by free radical decomposition of diazonium salts by titanium(n) chloride in the presence of a,/3-ethylenic ketones. 

A range of chloride metathesis reactions of the monomeric titanium N,N -bis(trimethylsilyl)benzamidinato-imido complexes have been described. These... 

Scheme 13.26. Highly enantioselective homoaldol addition with a chiral titanium N-allylurea reagent.

Alkoxides (titanium ethoxide, titanium n-propoxide, titanium n-butoxide, titanium sec-butoxide, titanium ethylhexoxide, aluminum sec-butoxide, zirconium n-propoxide, and their mixtures), typically 3 ml, sonicated with propylene carbonate, typically 17 ml, for 20-30 to form uniformly turbid emulsions. Immediate addition of water (10 mol excess) hydrolyzed the alkoxides. Precipitated oxide powders washed (in a Soxhlet extractor) with THF or 2-propanol for 21-30 h, dried, calcinated... 

Solution chemistry precursor solvent nitric acid content water content precursor concentration temperature Titanium n-butoxide (Ti(C4H90)4) methanol 0.125 mol/mol of precursor 4 mol/mol of precursor 0.625 mmol/mL of methanol room temperature Zirconium n-propoxide (Zr(CjH70)4) n-propanol 0.83 mol/mol of precursor 2 mol/mol of precursor 1.0 mmol/mL of n-propanol room temperature... 

Bis(cyclopentadienyl)titanium(n) Dicarbonyl, Isonitrile, and Phosphine Complexes 250... 

Bis(cyclopentadienyl)titanium(n) Complexes with Other Unsaturated Hydrocarbons 261... 

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