1.3- Thiazinium salts synthesis

Simple 6H- 1,3-oxazines and -thiazines are commonly encountered as intermediates in the reactions of oxazinium and thiazinium salts with nucleophiles (see Section 2.27.2.2.3). Additionally there is a considerable interest in 6//-1,3-thiazines as intermediates in the synthesis of cephem antibiotics (see Section 2.27.3.24) and many approaches have been... 

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