Three types of 2-alkenylthiazolines were designed and synthesized by a two-step method starting with 2-methylthiazoline and aromatic aldehydes, alkyl aldehydes and alkenyl aldehydes, respectively. Diels-Alder reactions of several 2-styryl-1,3-thiazolines with maleic anhydride in toluene were attempted. Expected Diels-Alder products were not observed or separated. Only starting materials were recovered. Several 2-alkenyl-1,3-thiazolines were successfully reacted with benzoyl chloride to form the N-benzoyl mono-substituted products. This is in sharp contrast with the di-benzoylation of 2-methylthiazoline reported previously by the Pittman group. 2-Methylbenzothiazole was reacted with different folds of aroyl chlorides. However, only di-aroylation products were observed even when a 1:1 2-methylbenzothiazole:aroyl chloride ratio was employed. Finally, N-methyl cyclic ketene N,O- and N,S-acetals were reacted with different alkylsulfonyl chlorides, respectively. Only di-substituted products were found in the N,O-acetal reacitons and only mono-substituted products were found in the N,S-acetal reactions even when different folds of sulfonyl chloride was employed.