Here stages e, d and p are the electron transfer, dissociation (bond rupture) and protonation, the RH, R(H 2 )H and R(H 2 )(H 2 )H are the hydrocarbons axerophtene and its hydrogenated products. The "standard" way, with the formation of vitamin A hydro-derivatives R(H 2 )X and R(H 2 ) (H 2 )X suggested in a number of publications , was incorrect. It is noteworthy that the studies , were performed in the early to mid-1960s and were also aimed at analytical goals: at that time the explosive development of world production of synthetic vitamins, including in the USSR, began, cf. .