The structure of the digitalislike and natriuretic factors identified as macrocyclic derivatives of the inorganic carbon suboxide.

The Natriuretic and Endogenous DigitalisLike Factors (EDLFs) are disclosed to be cyclomeric and macroring closed derivatives of the inorganic carbon suboxide. The macrocyclic cyclohexamer with six carbon suboxide units has a molar mass of 408.2 Da, as previously been found for the EDLF of animal origin. The anhydrous cyclohexameric factor is lipophilic but is transformed into more hydrophilic derivatives by the stepwise addition of water. Based on the present findings, it appears that EDLFs exist in solution as an equilibrium mixture of lipophilic and hydrophilic forms and not as a single chemical substance. This structural assumption better accounts for the earlier observed highly anomalous properties of EDLFs. The simultaneously found higher molar mass (4,100 and 4,900 Da) macrocyclic carbon suboxide derivatives are tentatively identified as the Natriuretic factors.