Poly condensed nitrogen heterocycles. V. Two novel ring systems: Pyrazolo[5,1‐c]‐1,2,4‐thiadiazine and pyrazolo[3,4‐c]‐1,2‐thiazine

The title compounds were obtained by reaction of aminopyrazoles IV and VII with ω‐acetophenonesulfonyl chloride (II, R = C6H5). In agreement with the general pattern of the distribution of electron density in the pyrazole nucleus, this work confirms that the position 4 of ring is the favoured site of electrophilic attacks.