Final answer:
A diastereomer of a benzene ring with adjacent bromine substitutions would be represented by structures with the bromines one or two carbons apart. Diastereomers are non-mirror image stereoisomers differing in the configuration at one or more stereocenters, and in cyclic sugars, they are known as alpha and beta anomers depending on the orientation around the anomeric carbon.
Step-by-step explanation:
The question revolves around identifying the diastereomer of a given organic structure. In organic chemistry, diastereomers are stereoisomers that are not mirror images of each other, as opposed to enantiomers which are non-superimposable mirror images. The first structure shown is a benzene ring with two adjacent bromine atoms, which represents a 1,2-disubstitution pattern, also known as the ortho-isomer. The diastereomers of this structure would be the 1,3- (or meta-) and the 1,4- (or para-) disubstituted isomers, which here are represented by the structures with bromines one and two carbons apart, respectively.
In the context of cycloalkanes and monosaccharides, a diastereomer is based on the orientation of the substituents around one or more stereocenters. For example, in trans-1,2-dimethylcyclopropane, switching only one of the methyl groups from the cis-form results in a diastereomer. In cyclical monosaccharides, the alpha and beta anomers differ in the position of the hydroxyl group relative to the anomeric carbon, with the alpha-form having the OH group downwards and the beta-form having it upwards.