Heterocyclic structures useful in medicinal chemistry: the case of pyrazino[2,3-c][1,2,6]thiadiazine 2,2-dioxide.

Different aspects of a particular kind of heterocycle, namely pyrazino[2,3-c][1,2,6]thiadiazine 2,2-dioxide are discussed. These include synthesis, reactivity, tautomerism and acid-base properties, results of x-ray analysis and molecular orbital calcultations. Besides, some of the derivatives have shown interesting biological effects, among which are the diuretic properties which are also presented.