Scheme 3 illustrates a method of synthesizing {HEAD ~ the R and S enantiomers} of the starting materials of {TAIL ~ the formula} VII wherein X is sulfur 
Scheme 3 illustrates a method of synthesizing { HEAD ~ the R and S enantiomers } of the starting materials of { TAIL ~ the formula } VII wherein X is sulfur
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH