Novel method for preparing styryl pyrazole, isoxazole and isothiazole derivatives

A method for synthesizing derivatives corresponding to formula (I):

• in which:
• R1, R2, R3, at the 2, 3, 4, 5 or 6 position of the phenyl ring, which are identical or different, are chosen from:
• a hydrogen atom;
• C1-C6 alkyls;
• C2-C6 alkenyls;
• C2-C6 alkynyls;
• halogens, C1-C6 haloalkyls;
• —OH;
• the groups —OR′, —SH, —SR′, —SeH, —SeR′, —C(O)R′, —NHC(O)R′, —C(S)R′, —NHC(S)R′, —CN in which R′ represents a group chosen from C1-C6 alkyls, C2-C6 alkenyls, C2-C6 alkynyls;
• the groups —C(O)OR″, —OC(O)R″, —NR″R′″ in which R″ and R′″, which are identical or different, represent a group chosen from a hydrogen atom, C1-C6 alkyls, C2-C6 alkenyls, C2-C6 alkynyls;
• X and Y represent a pair of atoms chosen from:
• (NR4, N) (pyrazole ring), (O, N) (isoxazole ring), (S, N) (isothiazole ring), R4 being chosen from:
• a hydrogen atom;
• C1-C6 alkyls;
• the groups CH2—OR5, the groups C(O)OR5 in which R5 is chosen from a hydrogen atom, a C1-C6 alkyl group, a benzyl group;
• the heterocycle is linked to the phenyl ring via its 3- or 5-position in the case of the pyrazole ring, via its 5-position in the case of the isoxazole and isothiazole rings;
• n represents an integer chosen from 0, 1, 2, 3, 4, 5 and 6;
• Z, at the 3- or 4-position of the isoxazole, pyrazole or thioxazole ring, represents a group chosen from:
• a hydrogen atom;
• C1-C6 alkyls;
• C2-C6 alkenyls;
• C2-C6 alkynyls;
• halogens, C1-C6 haloalkyls;
• —OH;
• the groups —OR′, —SH, —SR′, —SeH, —SeR′, —C(O)R′, —NHC(O)R′, —C(S)R′, —NHC(S)R′, —CN in which R′ represents a group chosen from C1-C6 alkyls, C2-C6 alkenyls, C2-C6 alkynyls;
• the groups —C(O)OR″, —OC(O)R″, —NR′R′″ in which R″ and R′″, which are identical or different, represent a group chosen from a hydrogen atom, C1-C6 alkyls, C2-C6 alkenyls, C2-C6 alkynyls, this method being characterized in that it comprises at least one step consisting in treating the product corresponding to formula (II) below in which R1, R2, R3, X, Y, Z and n have the same definition as in formula (I) above, in alcohol in the presence of a base to give the product of formula (I):
• A and B being chosen such that one of A and B is H, the other being —OH.