1: With 2,6-di-tert-butyl-4-methyl-phenol; 3 A molecular sieve; lithium chloride in dimethyl sulfoxide T=20 - 140°C; Krapcho dealkoxycarbonylation; 3 h; 2: With Candida antarctica lipase B; water T=17°C; 10 h; 3: With hydrogen; palladium on activated charcoal in ethanol; water 46 h; Further stages.;