The X-ray Structures of 2,4-Dibromothiazole and 2,4-Diacetyl-5-bromothiazole

Abstract

2,4-Dibromothiazole [orthorhombic, a = 6.700 (10), b = 16.21 (3), c = 5.516 (8) A, space group Fmm2] shows a disordered crystal structure with molecules randomly oriented with respect to the direction of the Br–C(2)–N–C(2)–Br unit and the remaining ring atoms S(3) and C(3)H showing mixed occupancy. 2,4-Diacetyl-5-bromothiazole [triclinic, a = 4.040 (2), b = 8.254 (5), c = 13.208 (8) A, α = 96.191 (17), β = 93.865 (16), γ = 94.067 (11)°, space group P-1] shows a structure dominated by halogen bonding, intramolecular between 4-COMe and 5-Br and intermolecular between 2-COMe of one molecule and 5-Br of the next. 2,4-Dibromothiazole is disordered in the crystal structure with molecules randomly oriented either way round as shown. There is evidence for unusual intramolecular, and perhaps also intermolecular, halogen bonding between Br and C = O in the structure of 2,4-diacetyl-5-bromothiazole.