With Replacement of Hydrogen Atoms

The acetyl-methyl group in 2-acetylphenyl methyl tellurium condenses with benzaldehyde to give methyl 2-(3 -phenyl-2 -propen-l -oyl)phenyl tellurium.  

Methyl 2-(3 -Phenyl-2 -propen-l -oyl)phenyl Tellurium A stirred mixture of 12 g (46 mmol) of 2-acetylphenyl methyl tellurium, 17.6 ml (18.4 g, 170 mmol) of benzaldehyde, 88 ml of acetic acid, and 35 ml of piperidine is heated under reflux for 6h. The mixture is then steam-distilled to remove unreacted benzaldehyde. The resultant red oil is separated by extraction with chloroform, the extract is evaporated, and the residue is fractionally distilled under vacuum. The fraction boiling above 200°/0.1 torr is collected and redistilled to give a condensate that should solidify. This solid is recrystallized several times from a mixture of petroleum ether and benzene yield 3.2 g (20%) m.p. 102-104° (from heptane/benzenc). 

3-Oxocyclopentyl and 3-oxocyclohexyl phenyl tellurium compounds reacted in tetrahydro-furan with butyraldehyde and benzaldehyde. The products of these aldol reactions were not isolated, but oxidized to the telluroxides that, in turn, were converted to enones by telluroxide elimination s. 

5-Dioxotellurane condensed with l-ethyl-2-(2 -anilinovinyl)quinolinium iodide and related compounds to form merocyanine dyes .  

Irgolic Organo Tellurium Compounds with 2 Te —C Bonds or 1 Te = C Bond 

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With Replacement of Hydrogen Atoms in the Tellurophene Ring... 

Amines are derived from ammonia by the replacement of hydrogen atoms with organic groups. Amides result from the condensation of amines with carboxylic acids. Amines and many amides take part in hydrogen bonding. 

This chapter deals with modifications of the physical and chemical properties of an organic molecule, which are induced by the replacement of hydrogen atoms by fluorines. These changes in the physicochemical properties play an important role in the behavior of the molecule when it is put into a biological environment. 

The amount of heat required to raise the temperature of a material is related to the vibrational and rotational motions thermally excited within the sample. Polymers typically have relatively (compared with metals) large specific heats, with most falling within the range of 1 to 2 kJ kg-1 K . Replacement of hydrogen atoms by heavier atoms such as fluorine or chlorine leads to lower Cp values. The Cp values change as materials undergo phase changes (such as that at the T ) but remain constant between such transitions. 

Techniques based on the replacement of hydrogen atoms in hydridechlorosilanes with alkyl, alkenyl and aryl radicals... 

The replacement of hydrogen atoms with deuterium caused large deuterium-induced isotope shifts in the 77Se NMR. For both conformers 45 and 46, the resonance of the deuterated compound shifted upfield with respect to the parent compound. The isotope shift (AS, an upfield shift) was 4.22 ppm for 45 and 4.03 ppm for 46. These values were definitely larger than that observed for 46 (AS = 3.78 ppm). These differences, AAS = +0.44 ppm for 45 and +0.25 ppm for 46, can be considered as the isotope shifts due to the C-H- -Se nonbonded interaction <1996BCJ1825>. 

Halt enation— The introduction of halogens into Mannich bases is usually carried out according to the well-known synthetic methods of organic chemistry (Table 30). In particular, the replacement of hydrogen atoms in the a or a position of P-aminoketones is performed with the aim of controlling the regioselcctivity of the reaction" ... 

Constructing a substitutive name generally involves the replacement of hydrogen atoms in a parent structure with other atoms or atom groups. Related operations, often considered to be part of substitutive nomenclature, are skeletal replacement (Section IR-6.2.4.1) and functional replacement in oxoacid parents (Section IR-8.6). Note that some operations in parent hydride-based nomenclature are not substitutive operations (e.g. formation of cations and anions by addition of H+ and H, respectively, cf. Sections IR-6.4.1 and IR-6.4.5). Names formed by the modifications of parent hydride names described in those sections are still considered part of substitutive nomenclature. 

Various substituted 2-pyrazolin-5-ones react with metal salts with replacement of hydrogen and formation of semipolar bonds with electron donating atoms. The most important of these compounds are the metal complexes of 4-arylazo-2-pyrazolin-5-ones. These complexes are widely used in the dye industry to give desired properties to 4-arylazo-2-pyrazolin-5-one dyes. Although a large number of metal-dye complexes have been used in dyeing, only a few such compounds have been characterized and reported in the literature. Usually a solution of the azo compound and an appropriate salt such as cupric chloride or nickel sulfate are mixed in solution and heated.326 The reaction is... 

Nitric acid and sulphuric acid react with toluene and nitrocompounds and sulphonic acids are formed as the result of the replacement of hydrogen atoms in the ring. The positions in the molecule taken by the entering group are the same as those taken by the halogens. 

The replacement of hydrogen atoms by deuterium (or tritium) atoms is the simplest catalytic change that can happen to a hydrocarbon it occurs with surprising ease on a number of metal surfaces, and it focuses on the reactivity of... 

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