| http://www.w3.org/ns/prov#value | - If R.sub.1 is present solely for blocking purposes in order to prevent attack at the 6-position during subsequent chemicalprocessing, then R.sub.1 may be selected from lower alkyl radicals, e.g. --CH.sub.3, or other alkyl radical having up to about 6 carbon atoms.On the other hand, the size or nature of the group may be selected because it is produced in a convenient reaction for preparing the pyr
|
