Conformational pseudo-polymorphism and hydrogen bonding: benzthiazide anhydrate and monohydrate, an antihypertensive drug

Studies on hydrogen-bonding patterns. The conformation and the hydrogen-bonding patterns of a benzthiazide molecule in anhydrate and monohydrate forms which heve been recently considered for sustematic studies due to many industrial applications such a drug polymorphs in pharmaceutical.Unespectedly the conformation of benzthiazide molecule significantly differs in the two crystal forms leading to a conformational "pseudo-polymorphism". The two molecules reveals, respectively, a J-like folded as ell as extended type conformations that have critical torsional flexibility along the C-C-S-C bonds and novel H-bonded sulfonamide motifs.