Crystal structure of Brinzolamide: a carbonic anhydrase inhibitor

In crystal structure of the title compound, C(12)H(21)N(3)O(5)S(3) [systematic name: (R)-4-ethyl­amino-2-(3-meth­oxy­prop­yl)-3,4-di­hydro-2H-thieno[3,2-e][1,2]thia­zine-6-sulfonamide 1,1-dioxide], there exist three kinds of hydrogen-bonding inter­actions. The sulfonamide group is involved in hydrogen bonding with the secondary amine and the meth­oxy O atom, resulting in the formation of layers parallel to the bc plane. The layers are linked by an N—H⋯O hydrogen bond involving a sulfonamide O atom as acceptor and the secondary amine H atom as donor, which gives rise to the formation of a unique bilayer structure. The absolute structure of the mol­ecule in the crystal was determined by resonant scattering [Flack parameter = 0.01 (4)].