[Dark transition of 1st level reduction products of porphyrins to 2d level].

Transition of the products of the first restoration of porphyrines to the second one in the darkness and practically in the absence of a reducer and oxygen has been studied. Its cause is the disproportioning of dyhydroform into tetrahydro- and the initial pigment. Regeneration of porphyrines under these conditions is also shown. The rate of both reactions significantly increases in the light.