The aim of the project is to investigate the influence of different aliphatic substituents on enol protons and the nature of hydrogen bond formed, when 3-methyl-4-thiorhodanine (3-methyl-1, 3-thiazolane-2, 4-dithione) is acylated with different aliphatic substituents. Which are CH3,CH2CH3, (CH2)2CH3, CH(CH3)2, CH2CH(CH3)2, cyclopropyl, cyclohexyl, C6H5CH2, CH2C(CH3)3, C(CH3)3, CH3CHCH2CH3, CH(CH2CH3)2, 1-adamantane. NaOH was used as base and this resulted in successfully acylating the first nine products which contain an enol proton which takes part in hydrogen bonding and for the last four substituents mixed C- and S- acylated products were obtained. When the base was changed to pyridine only S-acylated products were obtained for the substituents which had mixed products while using NaOH. Therefore leading to the conclusion that steric effects could have played a role in which reaction pathway to follow as the last four substituents have large negative steric effect constants. The correlation of the inductive effect (σ*) values was made by plotting the 13C chemical shift of the substituents and 1H NMR chemical shifts of the enol protons as a function of the σ* values. The results showed that there was no linear correlation. The influence of the steric effect was also analysed and neither was there a linear correlation. The 1H NMR of the enol protons had a high chemical shift value which ranged from 15.08-15.32 ppm which shows that the sulphur formed strong hydrogen bond. Future studies would include studying the influence of both steric and inductive effects of the substituents maybe this could give a clear correlation if both parameters are considered together.
|Uddannelser||Kemi, (Bachelor/kandidatuddannelse) Bachelor el. kandidat|
|Udgivelsesdato||9 mar. 2011|
- acylation with aliphatic acid chlorides