[Nitin_Naudiyal]

Why is 2-chlorobuta-1,3- diene CH₂=CCl-CH=CH₂ called as Chloroprene ?

and Why is its polymer [ CH₂=CCl-CH=CH₂ ]_n called as Neoprene ?

[DrCMS]

Why not google neoprene and isoprene it would have been quicker than posting this question.

[Nitin_Naudiyal]

Thank you for u r reply

I did go through wikipedia before posting a question here
all i got that these compounds are collectively termesas iso-prenoids.

But i couldnt find why are they called as iso - prene

[fledarmus]

They are called isoprenes because they are related to a very common biological motif, based on 2-methyl-1,3-butadiene. This motif can be assembled by organisms into an enormous variety of useful molecules including steroids and natural rubber.

If you are asking why specifically they were given the common name "isoprene" instead of some other name, it is probably a shortened from of isopropenylethylene.

[DrCMS]

Thank you for u r reply

I did go through wikipedia before posting a question here
all i got that these compounds are collectively termesas iso-prenoids.

But i couldnt find why are they called as iso - prene

You didn't read it properly then beacuse wikipedia gives the following explanition for the name of Isoprene

"Isoprene (short for isoterpene), or 2-methyl-1,3-butadiene, is a common organic compound with the formula CH2=C(CH3)CH=CH2. Under standard conditions it is a colorless liquid. However, this compound is highly volatile because of its low boiling point.

Isoprene (C5H8) is the monomer of natural rubber and also a common structure motif to an immense variety of other naturally occurring compounds, collectively termed the isoprenoids. Molecular formula of isoprenoids are multiples of isoprene in the form of (C5H8)n, and this is termed the isoprene rule. The functional isoprene units in biological systems are dimethylallyl diphosphate (DMADP) and its isomer isopentenyl diphosphate (IDP).

The singular terms “isoprene” and “terpene” are synonymous whereas the plurals “isoprenes” or “terpenes” refer to terpenoids (isoprenoids)."  http://en.wikipedia.org/wiki/Isoprene

and Neoprene

"DuPont first marketed the compound in 1931 under the trade name DuPrene, but its commercial possibilities were limited by the original manufacturing process, which left the product with a foul odor. A new process was developed, which eliminated the odor-causing byproducts and halved production costs, and the company began selling the material to manufacturers of finished end-products. To prevent shoddy manufacturers from harming the product's reputation, the trademark DuPrene was restricted to apply only to the material sold by DuPont.  Since the company itself did not manufacture any DuPrene-containing end products, the trademark was dropped in 1937 and replaced with a generic name, neoprene"  http://en.wikipedia.org/wiki/Neoprene


So isoprene gets its common name from its terpene structure. 
Chloroprene gets its common name to show its connection to isoprene.
Neoprene is just a made up marketing term to show its the new improved polychloroprene.

[Nitin_Naudiyal]

Thank you DrCMS and Fledarmus

[fledarmus]

Had to go back and look at the names again after DrCMS's comment - sorry, my guess at the name was dead wrong. The names isoprene and terpene both seem to have come into use sometime between 1830 and 1860, after turpentine but before the structure of either class was known. The names were not derived from the structures, but from the source and properties of the compounds.