VV and examine its biological properties. Comparison of this compound with IVa and the analog IVb, the latter t'wo synt'hesized by equivocal guanylation of the appropriate hydrazine, confirmed the assignment of the structure IV on the following grounds.(i) Derivatives.-In cont'rast'to V, which readily gave a benzal derivative, IVa was recovered unchanged after prolonged treat'nient. with benzaldehyde.(ii) Degradation.-Treat'nient of ...