Method of preparing cis-8b-methyldecahydro-2a,4a,6a,8a-tetraazacyclopenta[fg] acenaphthylene, cis-decahydro-2a,4a,6a,8a-tetraazacyclopenta[fg] acenaphthylene, cyclene and functionalised cyclenes

A method of preparing the cyclene of the formula (I):

• from triethylenetetraamine of the formula (VIII):
• or ethylenediamine of the formula (VIII′):
• characterized in that it comprises one or the other of the following series of successive steps:
• series of steps (I) comprising a step A of a one pot preparation of the compound of the formula (IIa):
• from the compound of the formula (VIII) as previously defined, followed by a step (B) of transformation of the compound of the formula (IIa) into the cyclene of the formula (I);
• series of steps (II), comprising a step (C) of preparation of the compound of the formula (IIb):
• from the compound of the formula (VIII) as previously defined, followed by a step (D) of transformation of the compound of the formula (IIa) into the cyclene of the formula (I);
• or
• series of steps (III), comprising a step (E) of preparation in one pot of the compound of the formula (IIa) as previously defined, from the compound of the formula (VIII′) as previously defined, followed by a step (B) of transformation of the compound of the formula (IIa) into the cyclene of the formula (I).