CPC C07D 311/72 (2013.01) [B01J 21/16 (2013.01); B01J 35/615 (2024.01); B01J 35/617 (2024.01); B01J 37/06 (2013.01)] | 19 Claims |
1. A process for preparing a compound of formula I or II
![]() wherein
R1, R2 and R3 independently of each other are selected from hydrogen and methyl,
R4 is selected from hydrogen and C1-C6-alkanoyl,
X is selected from C1-C20-alkyl and an isoprenyl moiety of formula X.a
![]() wherein
n is an integer of from 1 to 10 and
* indicates the attachment point to the rest of the molecule,
comprising the following steps:
a) providing a compound of formula III or IV.a or IV.b or IV.c,
![]() wherein
R1, R2 and R3 are as defined above,
R4a independently of each other is selected from hydrogen and C1-C6-alkanoyl,
R5 independently of each other is selected from hydrogen, C1-C6-alkyl, C1-C6-alkanoyl and benzoyl, and
R6 independently of each other is selected from C1-C4-alkyl,
b) reacting the compound III or IV.a or IV.b or IV.c provided in step a) with an unsaturated compound of formula V.a or V.b
![]() wherein
X is as defined above,
Y is selected from OH, halogen, —O—R11, —S—R12 and —SO2—R12,
R11 is selected from C1-C4-alkyl, C1-C4-alkanoyl and trifluoroacetyl, and
R12 is selected from C1-C6-alkyl, trifluoromethyl and phenyl, where phenyl is unsubstituted or substituted with 1, 2, 3, 4 or 5 radicals selected from halogen and methyl,
in the presence of an acid treated bentonite catalyst, and
c.1) in case a compound of the formula III, wherein both R4ª are hydrogen, is applied in step b), and in case R4 in compound I is selected from C1-C6-alkanoyl, reacting the condensation product obtained in step b) with a C2-C7-carboxylic acid or with a C2-C7-carboxylic acid anhydride in the presence of an esterification catalyst, or reacting the condensation product obtained in step b) with an activated C2-C7-carboxylic acid in the presence of a base,
or
c.2) in case a compound of the formula IV.a wherein at least one R5 is C1-C6-alkanoyl or benzoyl, is applied in step b),
treating the product obtained in step b) with a base and subsequently with an oxidizing agent,
or
c.3) in case a compound of the formula IV.a, wherein R5 independently of each other are selected from hydrogen and C1-C6-alkyl, is applied in step b),
treating the product obtained in step b) with an oxidizing agent,
or
c.4) in case a compound of the formula IV.b is applied in step b),
treating the product obtained in step b) with an acid.
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