By the action of 2-aminothiazole, 2-aminopyridines, and 2-aminopyrimidines, respectively, on 4-chloro-3-nitrocoumarin (3) the corresponding 4-heteroarylamino-3-nitrocoumarins 5–7 have been isolated in very good yields. Reactions of coumarins 6 and 7 with either aqueous tetrabutylammonium bisulfate/sodium hydroxide in a two phase system or 5% aqueous sodium hydroxide have been studied.
Process for preparing 3-(1-hydroxphenyl-1-alkoximinomethyl)dioxazines
申请人:Bayer Aktiengesellschaft
公开号:US06335454B1
公开(公告)日:2002-01-01
The present invention relates to a novel process for preparing 3-(1-hydroxyphenyl-1-alkoximinomethyl)dioxazines which are known as intermediates for preparing compounds having fungicidal properties (WO 95-04728). Furthermore, the invention relates to novel 3-(1-hydroxyphenyl-1-alkoximinomethyl)dioxazines, to novel intermediates for their preparation and to a plurality of processes for preparing the novel intermediates.
Process for preparing 3-(1-hydroxyphenyl-1-alkoximinomethyl) dioxazines
申请人:Bayer Aktiengesellschaft
公开号:US06005104A1
公开(公告)日:1999-12-21
The present invention relates to a novel process for preparing 3-(1-hydroxyphenyl-1-alkoximinomethyl)dioxazines which are known as intermediates for preparing compounds having fungicidal properties (WO 95-04728). Furthermore, the invention relates to novel 3-(1-hydroxyphenyl-1-alkoximinomethyl)dioxazines, to novel intermediates for their preparation and to a plurality of processes for preparing the novel intermediates.
The reaction of dialkyl acetylenedicarboxylates with 1‐aryl‐2‐nitroethanones in the presence of pyridine leads to dialkyl 5‐aryloyl‐isoxazole‐3,4‐dicarboxylates through a novel mechanism, which involves a [2+2] cycloaddition/ring opening/cyclization sequence.
Process for preparing 3-(1-hydroxyphenyl-1-alkoximinomethyl)dioxazines
申请人:——
公开号:US20020049319A1
公开(公告)日:2002-04-25
The present invention relates to a novel process for preparing 3-(1-hydroxyphenyl-1-alkoximinomethyl)dioxazines which are known as intermediates for preparing compounds having fungicidal properties (WO 95-04728). Furthermore, the invention relates to novel 3-(1-hydroxyphenyl-1-alkoximinomethyl)dioxazines, to novel intermediates for their preparation and to a plurality of processes for preparing the novel intermediates.