申请人:DSM IP ASSETS BV
公开号:WO2005049618A1
公开(公告)日:2005-06-02
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 B6 with well established utility.
一种用于制造3-未取代,3-单取代或3,3-二取代9-酰氧基-1,5-二氢-8-甲基吡啶并[3,4-e][1,3]二氧杂环己烯(I)的方法,以及可选地用于制造吡哆醇的方法,包括在基本缺乏溶剂和催化剂的情况下,在4-甲基-5-烷氧基-噁唑酮(II)和2-未取代,2-单取代或2,2-二取代4,7-二氢-(1,3)-二氧杂环己烯(III)之间进行加成反应,以产生主要包含适当的Diels-Alder加合物(IV)和适当的3-未取代,3-单取代或3,3-二取代1,5-二氢-8-甲基吡啶并[3,4-e][1,3]二氧杂环己烯9-醇(V)的产物混合物,通过减压蒸馏去除大部分未反应的噁唑酮和二氧杂环己烯起始物,向所述产物混合物中添加基本无水的有机酸,并在所述基本无水的有机酸存在下将Diels-Alder加合物IV重排为进一步的V,并通过减压蒸馏去除生成的烷醇,将富集的V与额外的羧酸酐酸化以产生所需的I,可选择地将此种制造的酰化产物I通过酸水解转化为吡哆醇,以实现去保护和去酰基化。吡哆醇是一种已知的维生素B6形式,具有已建立的实用性。