Patent ID: 8871975

Claim:
A process for the synthesis of a compound of formula (I): wherein 1-(4-methoxyphenyl)-4-penten-1-one of formula (II): is reacted, in the presence of a free radical initiator, with a compound of formula (III): wherein R′ and R″, which may be the same or different, each represent a linear or branched (C 1 -C 6 )alkyl group or R′ and R″ together form a (C 2 -C 3 )alkylene chain, it being possible for the ring thereby formed to be fused with a phenyl group, and Xa represents a group —S—C(S)—OR wherein R represents a linear or branched (C 1 -C 6 )alkyl group, to yield the adduct of formula (IV): wherein R, R′ and R″ are as defined hereinbefore, wherein the compound of formula (IV) is optionally isolated, the amine function of which may optionally be deprotected and converted into an acetamide function, which compound of formula (IV) is subjected to a cyclisation reaction in the presence of a free radical initiator to form the compound of formula (V): wherein the group represents a protected amine function defined as follows: wherein R′ and R″ are as defined hereinbefore, the amine function of which compound of formula (V) may optionally be deprotected, wherein the compound of formula (V) is either subjected to reduction-esterification followed by dehydration or converted into a vinyl halide to yield the compound of formula (VI): wherein Y represents a halogen atom or a hydrogen atom, and the group is as defined hereinbefore, the protected amine function of which compound of formula (VI) is converted into an acetamide function where applicable, i.e. when that conversion has not been carried out earlier, to yield the compound of formula (VI′): wherein Y is as defined hereinbefore, which compound of formula (VI′) is subjected to an aromatisation reaction to yield the compound of formula (I), which is isolated in the form of a solid.