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1,2-Dimethylcyclopropane is a cycloalkane consisting of a cyclopropane ring substituted with two methyl groups attached to adjacent carbon atoms. [1] It has three stereoisomers , one cis -isomer and a pair of trans - enantiomers , which differ depending on the orientation of the two methyl groups.
2-Methyl-2-butene (CAS 513-35-9) Index of chemical compounds with the same molecular formula This set index page lists chemical structure articles associated with the same molecular formula .
Le Bel-van't Hoff rule states that for a structure with n asymmetric carbon atoms, there is a maximum of 2 n different stereoisomers possible. As an example, D-glucose is an aldohexose and has the formula C 6 H 12 O 6. Four of its six carbon atoms are stereogenic, which means D-glucose is one of 2 4 =16 possible stereoisomers. [20] [21]
The possibilities for different isomers continue to multiply as more stereocenters are added to a molecule. In general, the number of stereoisomers of a molecule can be determined by calculating 2 n, where n = the number of chiral centers in the molecule. This holds true except in cases where the molecule has meso forms.
Stereochemistry, a subdiscipline of chemistry, studies the spatial arrangement of atoms that form the structure of molecules and their manipulation. [1] The study of stereochemistry focuses on the relationships between stereoisomers, which are defined as having the same molecular formula and sequence of bonded atoms (constitution) but differing in the geometric positioning of the atoms in space.
[2] [3] The term metamer was formerly used for the same concept. [4] For example, butanol H 3 C−(CH 2) 3 −OH, methyl propyl ether H 3 C−(CH 2) 2 −O−CH 3, and diethyl ether (H 3 CCH 2 −) 2 O have the same molecular formula C 4 H 10 O but are three distinct structural isomers. The concept applies also to polyatomic ions with the same ...
As an example, four of the carbon atoms of the aldohexose class of molecules are asymmetric, therefore the Le Bel–Van 't Hoff rule gives a calculation of 2 4 = 16 stereoisomers. This is indeed the case: these chemicals are two enantiomers each of eight different diastereomers : allose , altrose , glucose , mannose , gulose , idose , galactose ...
Various stereoisomers exist for (1R,3R)-1,2,3-trimethylcyclopentane. Because (1R,3R)-1,2,3-trimethylcyclopentane is a cycloalkane, its three methyl substituents are capable of exhibiting cis/trans isomerism.