Three peptide derivatives of primaquine were synthesized. The compounds were tested for radical curative antimalarial activity against Plasmodium cynomolgi in rhesus monkeys and blood schizonticidal antimalarial activity against Plasmodium berghei in mice. All three peptide derivatives showed activity against P. cynomolgi greater than that expected for the primaquine content of each prodrug. The toxicity of one of the peptide derivatives was less than that of primaquine in mice.

A comparison of the 13C nmr spectra of eight cinchona alkaloids in CDCls and in DMSO-d6 has pointed out some important chemical shift differences which should be useful in the identification of similar compounds. The 13C chemical shifts of carbons 2 and 6 of the quinuclidine ring can be used to distinguish between quinine and quinidine derivatives. Similarly, 13C chemical shifts of C-4' should provide a means of distinguishing between three and erythro compounds (quinine and 9-epiquinine derivatives). Solvent studies on these compounds show that intramolecular hydrogen bonding has a large effect on the 13C chemical shifts of the carbons 6, 7, and 4', indicating that 13C nmr will be a useful tool to study important conformational problems of these and related compounds.

These data suggest that polymorphisms within ASPN are not a major influence in susceptibility to hand or knee OA in US Caucasians.

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