Synthesis Of Sulfinates And 1,2,4,5-Tetrazines

Sulfinates are found to have a wide variety of significant biological properties including insecticidal, antifungal, anti-leukemia and antitumor. Besides, sulfinates are widely utilized as versatile sulfinylating agents for the synthesis of a diverse range of organosulfur compounds including sulfoxides and sulfinamides. Based on our previous observations on the synthesis of sulfinates, two new sulfinate syntheses and a new 1,2,4,5-tetrazine synthesis have been developed, and the major researches are listed as follows:1. Sulfination of nonactivated alcohols with arylsulfonylmethyl isocyanides. Recently, we have accomplished a direct sulfination of benzyl alcohols, a class of activated alcohols, with arylsulfonylmethyl isocyanides by an intramolecular reaction strategy. Complementary to this effort, a direct sulfination of nonactivated alcohols, which is still a long-standing challenge, has been developed by using three synthetic strategies in this thesis. Firstly, insertion of isocyanides into the O-H bonds of nonactivated alcohols facilitates in situ conversion of the hydroxyl groups into the corresponding aza-carboxylate groups, in which the nonactivated alcohols are activated because aza-carboxylate groups are better leaving groups compared with a hydroxyl group. Secondly, the in-situ-generated aza-carboxylates are further double activated by the combination of a Lewis acid [Bi(OTf) 3] and a Br?nsted acid(CCl3CO2H). Finally, the intramolecular rearrangement of the aza-carboxylates affords sulfinates.2. Sulfination of alcohols with sodium sulfonates. Recently, we have also accomplished a sulfonate synthesis by a five-membered ring rearrangement of arylsulfonylhydrazones. Considering arylsulfonylhydrazones are not commercial available, a direct sulfination of alcohols with sodium sulfonates has been developed in this thesis by a similar ring rearrangement that was in-situ-generated in the presence of trimethyl chlorosilane. The protocol is attractive due to its mild reaction conditions, available starting materials and wide alcohol scopes.3. 1,2,4,5-Tetrazine synthesis from arylsulfonylhydrazones. Complementary to the above sulfonate synthesis by rearrangement of arylsulfonylhydrazones, reaction of arylsulfonylhydrazones with an electrophilic reagent, N–chlorosuccinimide, has been performed, which afforded 1,2,4,5-tetrazines instead of the expected sulfinates in the presence of potassium hydroxide. As 1,2,4,5-tetrazines are found to have a wide variety of significant biological properties including insecticidal and antifungal, the reaction conditions for the synthesis of 1,2,4,5-tetrazine synthetic were optimized and the scope of the substrates was subsequently investigated.In summary, several convenient and environmentally benign approach es have been developed in this thesis for the synthesis of sulfinates and 1,2,4,5-tetrazines, two important class of compounds with potential insecticidal and antifungal activities. The preliminary bioassay of some of these compounds showed that they have a broad spectrum of anti-adhesion of sea creatures.