Levo- prefix

Prefix lev/levo-Prefix ar-Prefix dex/dextro-Prefix es-... 

In solution, enantiomers rotate the wave plane of linearly polarized light in opposite directions hence they are refered to as dextro"- or levo-rotatory , designated by the prefixes d or (+) and 1 or (-), respectively. The direction of rotation gives no clue concerning the spatial structure of enantiomers. The absolute configuration, as determined by certain rules, is described by the prefixes S and R. In some compounds, designation as the D- and L-form is possible by reference to the structure of D- and L-glyceraldehyde. 

The biological consequences of molecular shape can be dramatic. Look at the structures of dextromethorphan and levomethorphan, for instance. (The Latin prefixes dextro- and levo- mean "right" and "left," respectively.) Dextromethorphan is a common cough suppressant found in many over-the-counter cold medicines, but its mirror-image, levomethorphan, is a powerful narcotic pain-reliever similar in its effects to morphine. The two substances are chemically identical except for their shapes, yet their biological properties are completely different. 

Optical isomerism is when two molecules are nonsuperimposable mirror images of each other (Think of a pair of gloves. They can only stack palm to palm, not one on top of the other.) Such molecules are termed asymmetric or chiral. (Note Chiral carbons have 4 different substituents.) Two optical isomers can be distinguished in their names by the prefixes dextro- or levo- according to whether a solution of the compound rotates a beam of polarized light to the right or the left. The abbreviations d- and l- are commonly used for dextro- and levo-. A new system of naming uses R- (rectus) and S- (sinister). 

If an optically active compound rotates the plane of polarization clockwise, it is called dextrorotatory, indicated by (+). If an optically active compound rotates the plane of polarization counterclockwise, it is called levorotatory, indicated by (—). Dextro and levo are Latin prefixes for to the right and to the left, respectively. Sometimes lowercase d and I are used instead of (+) and (—). 

The active forms of dihydroxysuccinic acid are named dextro-tartaric acid and levo-tartaric acid. The former occurs widely distributed in nature, and is usually called tartaric acid, the prefix being omitted. The inactive acid which is a mixture of... 

The following prefixes and interpolations are not treated as part of the name ortho- (o-), meta- (m-), para- (p-), alpha- (a), beta- (p), gamma- (y) etc. primary- (prim-), secondary- (sec-), tertiary- (tert-), cis-, trans-, dextro- (d-), levo- (I-), normal (n-), N- (- bond to nitrogen atom). 

Rotation of the plane of polarized light in the clockwise sense is taken as positive (+), and rotation in the counterclockwise sense is taken as a negative ( —) rotation. Older terms for positive and negative rotations were dextrorotatory and levorotatory, from the Latin prefixes dextro- ( to the right ) and levo- ( to the left ), respectively. At one time, the symbols d and / were used to distinguish between enantiomeric forms... 

There are a number of dmgs such as dextrorophan and levorphan which are prefixed by dextro- or levo- to indicate... 

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