- 5 - 
It has further ruled that "Technical chlordane is the commercial pro- 
duct containing 60 percent to 75 percent of chlordane together with 25 
percent to 40 percent of other related compounds, ncr mally resulting from 
the manufacturing processes, and toxic to certain insects. All of its 
ingredients are, therefore, considered active under the Insecticide Act." 
SYNTHESIS 
The synthesis of chlordane is described in patents granted Hyman 
(23J2, 233 ). It is made "by combining hexachlorocyclopentadiene and cyclo- 
pentadiene to form a Diels-Alder addition product of the formula C .H^Cl,-, 
to which chlorine is added to form C^qH^CIs. 
The reaction is as follows: 
010' 
01 C 
/ 
9 1 
HO- 
-OH 
cci 2 + 
EC 
OH 
4 C1C 
C1C 
H, 
01 
0. 
CC1, 
c 
01 
H 
•CH 
'? 
(A) 
-H 
0/ 
The adduct is dissolved in carbon tetrachloride and treated with 
chlorine gas with the resultant addition of two atoms of chlorine to the 
double bond (A) to form chlordane: 
010 6 
01 C 
9 1 
0, 
3 
001, 
01 
7a 
CH- 
,CH- 
3a 
3H01 
2, CHOI 
-CH 2 
It is of interest to know that Riemschneider and Kuhnl ( 389 ) in 
Germany claim to have independently discovered the insecticidal properties 
of chlordane. They were led to prepare it from its structural analogy to 
cantharidin which they state is a contact insecticide. The structure of 
cantharidin is: 
