1,3-Diaryl-2-propen-1-ones 1 reacted with thiourea in the presence of sodium ethoxide to give 4,6-diaryl-3,4-dihydropyrimidine-2(1H)thiones 5 which upon dehydrogenation with 3 mol of ethanolic sodium ethoxide yielded the corresponding 4,6-diarylpyrimidine-2(1H)thiones 9. The N-acetyl derivatives of the former thiones were prepared. Infrared, nuclear magnetic resonance, and ultraviolet spectral data of the above compounds were tabulated and discussed.

The differences in the chemical composition of five asphalts and one air-blown bitumen, obtained from Kuwait crudes, were studied using the densimetric technique. Two asphalts were then reacted with different weight percent of sulfur at 220 °C, and the effect of sulfur was followed by studying the composition analysis of the products. The results obtained revealed that the reaction with sulfur leads to an increase in the percent of asphaltene, which contains most of the bonded sulfur. It was also found that the above reaction increases the average number of carbon atoms per molecule as well as the aromaticity. The addition of up to 5 wt % of sulfur led to no significant increase in the sulfur content of the products.

Nuclear magnetic resonance methods were used for the determination of average structural formulae and formula weights of the saturate, naphthene-aromatic, and polar-aromatic fractions separated from asphalts by elution adsorption chromatography. The average formula weights are compared to molecular weights, showing fair agreement in the majority of cases. The more polar fractions of one asphalt had molecular weights up to 4 times the formula weights, while the less polar fractions had molecular weights in excellent agreement with formula weights. The aromaticity, the degree of substitution, the nonaromatic carbon in naphthenic rings, and the atomic hydrogen/carbon ratio of the fractions were discussed.

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