A Mild and Efficient Triphosgene-Mediated Cyclodehydration of 2-(Imidoylthio)carboxamides. Synthesis and Chemistry of 4-Amino-2-(Methylthio)thiazolium Chlorides

ChemInform Abstract: 5‐Aminothiazolium Salts as Potential Cyclic Azomethine Ylides — Base‐Induced Intramolecular Cycloaddition Reactions of N‐(o‐Allylphenyl)‐ and N‐(o‐(Allyloxy)phenyl)‐Substituted Derivatives.

“…On the contrary, hydrolysis and ring-opening the pendant olefin when the 2-allylphenyl group is connected to the endocyclic N-3. We described here the prep-situ technique [6] with standard electrophilic alkynes and alkenes [7] and carbon disulfide [8] . The structural assignments of the The synthesis and chemical behaviour of mesoionic ring one of the most powerful methods for the generation of complex systems [2] [9] .…”

“…The reaction leads to the or oxidation and rearrangement of the mesoionic intermediates are the exclusive base-promoted conversions of formation of original N-bridged thiazoloquinolines as a mixture of two regioisomers 3 ,4 which are readily separated other thiazolium salts 1. by chromatography. For instance, use of Results and Discussion CS 2 gave thiazolium-5-thiolates via a subsequent elimination of tert-butyl isothiocyanate [8] .Preparation of Thiazolium Salts 1.As key model we chose to investigate the behaviour of the 5-aminothiazolium sys-We now investigated some examples of the internal olefinic version of these cycloaddition reactions, with the view tem derived from ortho-allyl and ortho-(allyloxy) anilines or benzaldehyde, such that the benzene backbone containing to construct ring-annulated multicyclic compounds. Such reactions have been studied with systems have received much attention in the last twenty years [1] [2] .…”

“…The reaction leads to the or oxidation and rearrangement of the mesoionic intermediates are the exclusive base-promoted conversions of formation of original N-bridged thiazoloquinolines as a mixture of two regioisomers 3 ,4 which are readily separated other thiazolium salts 1. by chromatography. For instance, use of Results and Discussion CS 2 gave thiazolium-5-thiolates via a subsequent elimination of tert-butyl isothiocyanate [8] . Such reactions have been studied with systems have received much attention in the last twenty years [1] [2] .…”

“…In particular, we showed that the treatment of an aryl chlorodithio or chloro-synthetic approaches to several natural products. We described here the prep-situ technique [6] with standard electrophilic alkynes and alkenes [7] and carbon disulfide [8] . To date, however, the use of mesoionic media for cyclic azomethine ylides.…”

“…Another interesting example is the intramolecular cycloaddition of thionoformate with a mixture of N-benzylidenealkylamine and tert-butyl isocyanide smoothly afforded the 5-(tert-bu-a Reissert salt or open-chain analogue (5-aminooxazolium tetrafluoroborate) on a monosubstituted alkyne to produce tylamino)-4-phenylthiazolium chlorides 1 (R 2 ϭ PhS or p-TolO, R 3 ϭ alkyl) which are potential precursors in basic a fused pyrrole by HNCO evolution from the primary dipolar adduct [17] . For instance, use of Results and Discussion CS 2 gave thiazolium-5-thiolates via a subsequent elimination of tert-butyl isothiocyanate [8] . Reactivities of the corresponding mesoionic thiazoles 2 were examined by the in thiazoles as cyclic azomethine ylides in similar internal reactions was unprecedented.…”