The synthesis of the full family of bromothiazoles has been revisited in order to update and optimize their production. The species reported include 2-bromothiazole, 4-bromothiazole, 5-bromothiazole, 2,4-dibromothiazole, 2,5-dibromothiazole, 4,5-dibromothiazole, and 2,4,5-tribromothiazole, the majority of which are produced via sequential bromination and debromination steps. This complete family can now be produced without the use of elemental bromine, and the presented methods have allowed the physical and NMR spectroscopic characterization of the full family to be reported for the first time.

New synthetic methods have been developed for the preparation of 4-alkyl- and 4-aryl-pyrrolo[2,3-d:5,4-d']bisthiazole (PBTz) building blocks from 2,4-thiazolidinedione. The resulting PBTz products have been fully characterized via structural, electronic, and optical methods, thus allowing full comparison to the previously reported dithieno[3,2-b:2',3'-d]pyrrole (DTP) analogues. Such comparisons then allow a detailed discussion of the relative electronic effects of the various methods utilized to tune the properties of the parent DTP building block.

The preparation of tetrabutylammonium bis[2‐(2‐thienyl)‐4,5‐thiazoledithiolato]nickelate(1–) is presented as the first example of a new family of π‐extended fused‐ring metal dithiolenes. The optical, electronic, and structural properties of this complex have been characterized by UV/Vis‐NIR spectroscopy, cyclic voltammetry, and X‐ray crystallography. Comparison of these properties to the analogous nickel thiophenedithiolene shows that incorporation of nitrogen into the fused ring stabilizes the frontier orbitals of the thiazole‐based complex, while preserving the planar geometry, electronic delocalization, and low‐energy NIR absorption of the previous thiophene‐based species.

No abstract

SummaryThe one-pot cyclization of 5-hexynoic acid to produce 3-alkoxy-2-cyclohexenones proceeds in good yields (58–90%). 3-Hexynoic acid was converted to its acyl chloride with the aid of oxalyl chloride and was cyclized to 3-chloro-2-cyclohexenone upon addition of indium(III) chloride. Subsequent addition of alcohol nucleophiles led to the desired 3-alkoxy-2-cyclohexenones.