prov:value
| - by O, NH, NR5, or S, where R5 is a C1 -C3 alkyl; and A is N, or a N-containing substituted or unsubstituted C1 -C30 straight chain or cyclic alkyl compound which may also be internally interrupted by O, NH, NR5, or S, where R5 is a C1 -C3 alkyl; z is 1 to 10; provided that at least one of R1 and R2 is other than H, at least one of R3 and R4 is other than H, at least one of said A groups comprises
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