Reactions of Thiiranes with NH Heterocycles: II. C-Bromo/Nitro-1-(thietan-3-yl)pyrazoles as Convenient Synthons for Substituted 1-(Thietan-3-yl)pyrazoles

Reactions of 2-(chloromethyl)thiirane with symmetrically substituted C -bromo/nitropyrazoles in water in the presence of bases were accompanied by thiirane–thietane rearrangement to afford 4-bromo(nitro)- and 3,5-dibromo-4-bromo(nitro)-1-(thietan-3-yl)-1 H -pyrazoles as convenient intermediate products for further transformations. Possible modifications of the title compounds via oxidation to 1-(1-oxo-λ 4 -thietan-3-yl)- and 1-(1,1-dioxo-λ 6 -thietan-3-yl)pyrazoles, reactions with oxygen and nitrogen nucleophiles with the formation of thietane-containing 5-methoxy- and 5-(morpholin-4-yl)-1 H -pyrazoles, and reduction to 4-amino-3-bromo-5-(morpholin-4-yl)-1-(thietan-3-yl)-1 H -pyrazole have been demonstrated.