PRIMARY AND SECONDARY 5-(ALKYLOXY)THIANTHRENIUM PERCHLORATES - CHARACTERIZATION WITH H-1-NMR SPECTROSCOPY, REACTIONS WITH IODIDE AND BROMIDE ION, AND THERMAL-DECOMPOSITION IN SOLUTION

A series of 5-(alkyloxy)thianthrenium perchlorates has been made in wh ich the alkyl group is primary (la-lp) and secondary (2a-2g). Preparat ions were carried out by reaction of the corresponding alkanol with th ianthrene cation radical perchlorate in CH2Cl2 solution followed by pr ecipitation of the perchlorate salt with dry ether. H-1 NMR spectrosco py reveals that the presence of a stereogenic center in the alkyl grou p causes inequivalence in the ordinarily paired protons (e.g., H-4, H- 6) of the thianthrenium ring. Reaction of iodide and bromide ion with primary alkyl-group compounds (e.g., methyl, ethyl, propyl, butyl) gav e the alkyl halide in very good yield and by a second-order kinetic di splacement. The second product was thianthrene 5-oxide (ThO). Rate con stants for some of these reactions are reported. Reaction of secondary alkyl group compounds (e.g., 2-propyl, 2-pentyl, 2-hexyl, and 3-hexyl ) with iodide ion gave good yields of alkyl iodide but also increasing evidence for a side reaction at the sulfonium sulfur, leading to I-2, thianthrene, and secondary alkanol. Decomposition of some compounds a t 100 degrees C in solution (acetonitrile or 1,2-dichloroethane) was s tudied and gave alkene(s) and ThO.