Abstract: The present invention is directed to a method for demethylating 14-hydroxy substituted alkaloid derivatives, in particular of 14-hydroxy-17-methyl-4,5-epoxymorphinane-6-on-derivatives. This is achieved by reacting a starting compound with a compound of general formula R1OOC—N?N—COOR2 in a suitable solvent.

Abstract: The present invention relates to a process for the preparation of quaternary N-alkyl morphin or morphinan alkaloid derivatives. This is achieved by using a nucleophilic nitrogen, phosphor or sulfur containing base in the reaction mixture.

Abstract: A process for preparing 17?-substituted 4-azaandrost-1-en-3-one compounds of the general formula (I): or a pharmaceutically approved salt thereof, where R is hydroxyl, optionally substituted, linear or branched (C1-C2)alkyl or (C1-C12)alkenyl; phenyl or benzyl; an —OR1 radical, or an —NHR1 radical, or an —NR1R2 radical; R1 is hydrogen, optionally substituted, linear or branched (C1-C12)alkyl or (C1-C12)alkenyl, or optionally substituted phenyl; R2 is hydrogen, methyl, ethyl or propyl; or —NR1R2 is a 5- or 6-membered heterocyclic ring, by (A) introducing protecting groups into the 3-keto-4-aza moiety of the corresponding 1,2-dihydro compound, so that a compound of the general formula (III) is formed: where R3 is trialkylsilyl or, together with R4, the —C(O)—C(O)— or —C(O)—Y—C(O)— radical; R4 is alkyloxycarbonyl or phenyloxycarbonyl, preferably Boc (=tert-butyloxycarbonyl); or trialkylsilyl, or, together with R3, the —C(O)—C(O)— or —C(O)—Y—C(O)— radical; Y is —[C(R5)(R6)]n— or —CH(R5)?CH(R6)—, or ort

Abstract: The present invention is directed to a method for demethylating 14-hydroxy substituted alkaloid derivatives, in particular of 14-hydroxy-17-methyl-4,5-epoxymorphinane-6-on-derivatives. This is achieved by reacting a starting compound with a compound of general formula R1OOC—N?N—COOR2 in a suitable solvent.

Abstract: Disclosed is a method for producing d-threo-[R(R*,R*)]-2-phenyl-2-piperidine-2-yl acetate and the acid addition salts thereof by converting d-threo-[R(R*,R*)]-2-phenyl-2-piperidine-2-yl ethanoic acid or an acid addition salt thereof into the corresponding d-threo-[R(R*,R*)]-2-phenyl-2-piperidine-2-yl ethanoic acid halide, producing the desired d-threo-[R(R*,R*)]-2-phenyl-2-piperidine-2-yl-acetate or an acid addition salt thereof by means of esterification, and optionally recrystallizing the obtained product. The invention also relates to methods for producing pure threo-2-phenyl-2-piperidine-2-yl acetamide or the starting material for producing d-threo-[R(R*,R*)]-2-phenyl-2-piperidine-2-yl ethanoic acid.