Patent ID: 8658808

Claim:
A process for preparing a compound of the formula Ia or a salt thereof; which comprises heating a compound of the formula VII with a base B and a zeolite catalyst, wherein base B is selected from the group consisting of diisopropylethylamine, tri-n-butylamine, tri-n-propylamine, N,N-dimethyaniline, N,N-diethylaniline, N-methyl-imidazole, N-ethyl-imidazole, N-propyl-imidazole, N-butyl-imidazole, collidine, 2,6-lutidine, 1,4-diazabicyclo-[2,2,2]-octane, 2,2,6,6-tetramethyl-piperidine and quinuclidine.