Patent ID: 8704002

Claim:
A method for converting a compound of Formula I wherein R 1 represents H or C 1-5 -alkyl, R 1′ represents H or C 1-5 -alkyl, R 2 represents H or C 1-5 -alkyl, R 3 represents H or C 1-5 -alkyl, R 4 , R 4′ , R 5 , R 5′ , R 6 , which may be identical or different, each represents H, OH, C 1-4 -alkyl, OC 1-4 -alkyl, partially fluorinated or perfluorinated C 1-4 -alkyl, partially fluorinated or perfluorinated O—C 1-4 -alkyl, O—(CH 2 ) n -phenyl where n=1, 2 or 3, F, Cl or OR 8 , or two adjacent radicals R 4 and R 5 , R 5 and R 6 , R 6 and R 5′ or R 5′ and R 4′ represent a group —OCH═CHO—, —CH═C(R 9 )—O—, —CH═C(R 9 )—S— or —CH═CH—C(OR 10 )═CH— as part of a ring, with the proviso that the other radicals in each case R 6 , R 5′ and R 4′ ; R 4 , R 5′ and R 6′ ; R 4 , R 5 and R 4′ or R 4 , R 5 and R 6 are as defined above, R 8 represents CO—C 1-5 -alkyl, PO(O—C 1-4 -alkyl) 2 , CO—C 6 H 4 —R 11 , CO(O—C 1-5 -alkyl), CO—CHR 12 —NHR 13 , CO—NH—C 6 H 3 —(R 14 ) 2 or an unsubstituted or substituted pyridyl, thienyl, thiazoyl or phenyl group, R 9 represents H or C 1-4 -alkyl, R 10 represents H or C 1-3 -alkyl, R 11 represents OC(O)—C 1-3 -alkyl in the ortho-position or —CH 2 —N—(R 15 ) 2 in the meta- or para-position, where R 15 in each case represents C 1-4 -alkyl or the two radicals R 15 , together with the bridging nitrogen atom, form a 4-morpholino radical, R 12 and R 13 , which may be identical or different, each represents H, C 1-6 -alkyl or C 3-8 -cycloalkyl, or R 12 and R 13 together represent —(CH 2 ) 3-8 as part of a ring, R 14 represents H, OH, C 1-7 -alkyl, partially fluorinated or perfluorinated C 1-7 -alkyl, OC 1-7 -alkyl, phenyl, O-aryl, F or Cl, with the proviso that the radicals R 14 are identical or different, wherein in each case the compound of Formula I is in the form of one of its pure stereoisomers, a racemate, or in the form of a mixture of stereoisomers, in any desired mixing ratio, or in each case in the form of a physiologically acceptable salt, or in each case in the form of a solvate, comprising dehydrating the compound of Formula I via catalysis carried out in the presence of a polyfunctional heterogeneous catalyst to form a compound of Formula II wherein R 1 , R 1′ , R 2 , R 3 , R 4 , R 4′ , R 5 , R 5′ and R 6 are as defined above, in each case in the form of one of its pure stereoisomers, a racemate, or a mixture of stereoisomers, in any desired mixing ratio, or in each case in the form of a physiologically acceptable salt, or in each case in the form of a solvate.