CL 
Tetrahydro- 
Phthalimide 
Cysteine 
O 
Be 
/ 
O 
70 
ro 
ll 
~C-OH 
2-Thiazolidine~ 
thione-4-carboxylic 
Acid 
ASO 
oO= 
\ 
‘NH 
-. 
+ HS + 
(CSC1,), 
Di(thiophosgene) 
cs + 
A=O>=O 
HS 
