8H-Anhydro-4-hydroxy-2-oxo-1,3-thiazinium Hydroxides as mesoionic 1,4-Dipoles

Article abstract of DOI:10.3987/COM-93-S(B)16

The previously unknown 8H-anhydro-4-hydroxy-2-oxo-1,3-thiazinium hydroxides (1) were prepared and their 1,4-dipolar cycloaddition behavior was examined.In most cases, elimination of the proton in the 8-position of the mesoionic ring was observed to occur unless extremely reactive dipolarophiles were used.The S,N-ketene acetals were converted to the corresponding α-diazo ketones for further study.