Tritium-labelled benzene, preparation

A nucleogenic phenyl cation has been generated by -decay of tritium-labeled benzene and reacted with methyl-substituted quinolones. A double tritium-labeled benzene (216) was prepared from 1,4-dibromobenzene. Decay of a tritium leads to the phenyl cation (217) and this cation reacts with 8-methylquinoline to give products (218) and (219). 

The crude reaction product purified by preparative GLC was subjected to Fourier-transform tritium NMR spectrometry to evaluate the isotopic composition of the labeled benzene. 

The borohydride reduction of 2 - and 3 -ketocytidine derivatives having or lacking an N4-acetyl group provided a facile route to cytosine nucleosides labeled with tritium at specific positions of the sugar.28 Reduction of either 20a or 20c with sodium borohydride in ethanol-benzene afforded the arabino and the ribo derivatives in the ratio of 4 1. Treatment of the reduction mixture with methanolic ammonium hydroxide gave the deacetylation products, 82b and 19b, isolated in crystalline form by preparative, thin-layer chromatography. 

Water is poorly soluble in hydrocarbons and determination of its solubility by ordinary chemical analysis requires a large amount of hydrocarbon samples. The solubility of water in benzene (Joris and Taylor 1948) and other hydrocarbons (Black et al. 1948) was determined with the use of tritium ( H, T) as tracer. These studies give an example where correction for the mass difference between an element of natural isotopic composition and its radioactive tracer is necessary. Water labeled with T was prepared by bombardment of heavy water (D2O) with... 

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See also in sourсe #XX -- [ ]

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