Sulfonic acid esters thioethers

Phthalocyanine sulfonic acids, which can be used as direct cotton dyes (1), are obtained by heating the metal phthalocyanines in oleum. One to four sulfo groups can be introduced in the 4-position by varying concentration, temperature, and reaction time (103). Sulfonyl chlorides, which are important intermediates, can be prepared from chlorosulfonic acid and phthalocyanines (104). The positions of the sulfonyl chloride groups are the same as those of the sulfonic acids (103). Other derivatives, eg, chlormethylphthalocyanines (105—107), / /f-butyl (108—111), amino (112), ethers (109,110,113—116), thioethers (117,118), carboxyl acids (119—122), esters (123), cyanides (112,124—127), and nitrocompounds (126), can be synthesized. 

Figure 4.8. The sulfur cycle where S° is elemental sulfur, H2S is hydrogen sulfide, S2032" is thiosulfate, SO32" is sulfite, SO/- is sulfate, R-OSO3H represents a sulfate ester, R-SO3H a sulfonic acid, R-S-R a thioether, and R-SH a thiol. (Adapted from Coyne MS. Soil Microbiology An Experimental Approach. Boston Delmar Publishers 1999.)...

X0 compds. 32, 181 perchloric acid esters 31,205 phosphonic acids 31,590 selenides 31, 813 -, sym. 32, 596 silanes 31, 592 sulfilimines 32, 368 sulfonic acid chlorides 31,548 thioethers 31, 560 -, preferential conversion 32, 553... 

No or little ring closure can be expected in chains containing less than six amino acid residues. For better control it appears to be preferable to apply esters which are fairly inactive but can be activated when cyclization is desired. For instance, oxidation of a thioether to the electron-withdrawing sulfone... 

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