A method of preparing a compound of Formula I or II, wherein, R 1 is selected from the group consisting of hydroxyl and C 1-5 alkoxy; R 2 and R 4 are in each instance independently selected from the group consisting of hydrogen, -C 1-5 alkyl, -CF 3, cyano, nitro, phenyl, -C R 6, -NR a R b, -C OR 6, -O-C R 6, -O-R 6, -O-R 6, -C =C(R 6) 2, -N C R 6, halo, -N(R 6) 3; wherein, R a and R b are each independently hydrogen or C 1-5 alkyl; wherein, R 6 is hydrogen or C 1-5 alkyl; R 3 is selected from the group consisting of hydrogen, linear or branched C 1-10 alkyl; R 5 is selected from the group consisting of hydrogen, C 1-5 alkyl, C 1-5 alkenyl and prenyl; comprising: dosing at a first temperature above 70 °C to about 200 °C a compound of Formula Ia wherein, R 5 is as described above; to a first mixture, said first mixture comprising an amine and a compound of Formula Ib wherein, R 1a is selected from the group consisting of hydroxyl and C 1-5 alkoxy; R 2a and R 4a are each as described above for R 2 and R 4; R 3a is selected from the group consisting of hydrogen, linear or branched C 1-10 alkyl; and R 7 is selected from the group consisting of hydrogen, -C R c, wherein R c is hydrogen or C 1-5 alkyl; wherein, the molar equivalents of the compound of Formula Ia to the compound of Formula Ib is 0.9 to 1.18; to form a second mixture; and, allowing the second mixture to react at a second temperature; wherein, a compound of Formula I or II is prepared. R 1 is selected from the group consisting of hydroxyl and C 1-5 alkoxy; R 2 and R 4 are in each instance independently selected from the group consisting of hydrogen, -C 1-5 alkyl, -CF 3, cyano, nitro, phenyl, -C R 6, -NR a R b, -C OR 6, -O-C R 6, -O-R 6, -O-R 6, -C =C(R 6) 2, -N C R 6, halo, -N(R 6) 3; wherein, R a and R b are each independently hydrogen or C 1-5 alkyl; wherein, R 6 is hydrogen or C 1-5 alkyl; wherein, R a and R b are each independently hydrogen or C 1-5 alkyl; wherein, R 6 is hydrogen or C 1-5 alkyl; R 3 is selected from the group consisting of hydrogen, linear or branched C 1-10 alkyl; R 5 is selected from the group consisting of hydrogen, C 1-5 alkyl, C 1-5 alkenyl and prenyl; dosing at a first temperature above 70 °C to about 200 °C a compound of Formula Ia wherein, R 5 is as described above; to a first mixture, said first mixture comprising an amine and a compound of Formula Ib wherein, R 1a is selected from the group consisting of hydroxyl and C 1-5 alkoxy; R 2a and R 4a are each as described above for R 2 and R 4; R 3a is selected from the group consisting of hydrogen, linear or branched C 1-10 alkyl; and R 7 is selected from the group consisting of hydrogen, -C R c, wherein R c is hydrogen or C 1-5 alkyl; wherein, the molar equivalents of the compound of Formula Ia to the compound of Formula Ib is 0.9 to 1.18; R 1a is selected from the group consisting of hydroxyl and C 1-5 alkoxy; R 2a and R 4a are each as described above for R 2 and R 4; R 3a is selected from the group consisting of hydrogen, linear or branched C 1-10 alkyl; and R 7 is selected from the group consisting of hydrogen, -C R c, wherein R c is hydrogen or C 1-5 alkyl; wherein, the molar equivalents of the compound of Formula Ia to the compound of Formula Ib is 0.9 to 1.18; to form a second mixture; and, allowing the second mixture to react at a second temperature; wherein, a compound of Formula I or II is prepared.