Dsm IP Assets B.v.

Jocelyn Fischesser

Werner Bonrath

Reinhard Karge

Christof Wehrli

Raphael Beumer

Lisa Giraudi

Andrew George Gum

Hongyan Shen

Frank Eisele

Francesco Pace

Konrad Witzgall

Helmut Fritsch

Ralf Keuper

The present invention relates to an improved process for the manufacture of 2,6-dimethyl-5-hepten-1-al.

Process for the manufacture of 2,6-dimethyl-5-hepten-1-al

The present invention relates to a novel process for the manufacture of Grewe-diamine comprising the following step: hydrolyzing a compound of formula (II), wherein R is hydrogen or straight- or branched chain C1-4 alkyl, with an aqueous alkali or alkaline-earth metal hydroxide solution, characterized in that the hydrolysis is carried out in the presence of an organic solvent.

Process for the manufacture of a precursor of vitamin B1

The present invention is directed to a process for the manufacture of 2-pentyn-1-ol starting from 2-propyn-1-ol via the following intermediates (I), (II) wherein Ris H or linear Calkyl, Ris linear Calkyl or branched Calkyl and Ris linear Calkyl, as well as to the intermediates themselves. 

Process for the manufacture of 2-pentyn-1-ol

A process for the preparation of 4-methyl-oxazole-5-carboxamide, an intermediate in the synthesis of pyridoxine, by reacting lower alkyl 4-methyl-oxazole-5-carboxy-late with a molar excess of anhydrous, liquid ammonia.

Process for 4-methyloxazole-5-carboxamide

The invention relates to a process for the catalytic conversion of a carbohydrate, an alcohol, an aldehyde or a polyhydroxy compound in the presence of a catalyst containing gold in a solvent.

Reaction with a gold catalyst

A process for manufacturing a 3-unsubstituted, 3-monosubstituted or 3,3-disubstituted 9-acyloxy-1,5-dihydro-8-methylpyrido[3,4-e] [1,3]dioxepin (I) and optionally for manufacturing pyridoxine involves performing an addition reaction between a 4-methyl-5-alkoxy-oxazole (II) and a 2-unsubstituted, 2-monosubstituted or 2,2-disubstituted 4,7-dihydro-(1,3)-dioxepin (III) in the substantial absence of a solvent and a catalyst to give a product mixture consisting essentially of the appropriate Diels-Alder adduct (IV) in a major proportion and the appropriate 3-unsubstituted, 3-monosubstituted or 3,3-disubstituted 1,5-dihydro-8-methylpyrido[3,4-e] [1,3]dioxepin 9-ol (V) in a minor proportion, removal of a substantial proportion of the unreacted oxazole and dioxapin starting materials from the product mixture by distillation under reduced pressure, addition of a substantially anhydrous organic acid to said product mixture and rearrangement of the Diels-Alder adduct IV to further V in the presence of said substantially anhydrous organic acid with removal of the generated alkanol by distillation under reduced pressure, and acylation of the resultingly enriched quantity of V with an added carboxylic acid anhydride to produce the desired I, and optionally converting this so-manufactured acylation product I to pyridoxine by acid hydrolysis for achieving deprotection and deacylatiom. Pyridoxine is a well known form of vitamin Bwith well established utility.

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Wittenheim, France

Jocelyn Fischesser