Process for the synthesis of trisubstituted oxazoles

A process for preparing an oxazole of formula (II):

• comprising reacting thiourea with a diketone ester of formula (I):
• wherein groups R1, R2, and R3, which are identical or different, are chosen from:
• saturated and unsaturated, linear and branched C1-C12 hydrocarbon groups, wherein said C1-C12 hydrocarbon groups are unsubstituted or substituted by at least one substituent chosen from —OR, —SR, —NRR′, —COOR, —CN, —SOnCH3, —CF3, and halogens;
• aryl groups unsubstituted or substituted by at least one substituent chosen from saturated and unsaturated, linear and branched C1-C12 hydrocarbon groups, —OR, —NRR′, —COOR, —CN, —SOnCH3, —SR, —CF3 and halogens;
• and
• saturated and unsaturated C5-10 heterocyclic groups comprising at least one heteroatom chosen from N, S, and O, wherein said heterocyclic groups are unsubstituted or substituted by at least one substituent chosen from linear and branched C1-C12 hydrocarbon groups, —OR, —NRR′, —COOR, —CN, —SOnCH3, —SR, —CF3, and halogens,
• wherein R and R′, which are identical or different, are each chosen from hydrogen atoms and saturated and unsaturated, linear, branched, and cyclic C1-C12 hydrocarbon groups, and n has a value chosen from 0, 1, and 2.