An environmentally benign and practical preparation method for the Vilsmeier-Haack reagent (VH) has been developed by using phthaloyl dichloride with DMF in toluene or 2-chlorotoluene. Phthalic anhydride as the byprod...An environmentally benign and practical preparation method for the Vilsmeier-Haack reagent (VH) has been developed by using phthaloyl dichloride with DMF in toluene or 2-chlorotoluene. Phthalic anhydride as the byproduct was recovered in high yield by simple filtration. Some aromatic acids have been transformed into the corresponding acid chlorides in good yields by employing the isolated VH. Treatment of primary or secondary alcohols with VH gave alkyl formates or alkyl chlorides by depending on the reaction conditions.展开更多
Two species of N-arylpyrazoles containing active amino group were synthesized.And formylations of N-arylpyazoles containing amino in different position of pyrazole rings using Vilsmeier-Haack reaction gave a series of...Two species of N-arylpyrazoles containing active amino group were synthesized.And formylations of N-arylpyazoles containing amino in different position of pyrazole rings using Vilsmeier-Haack reaction gave a series of useful pyrazole intermediates.The important features of this protocol were cheap materials,easy process,mild reaction conditions and good yield of products.展开更多
Acetylation and benzoylation reactions of certain aromatic aldehydes, ketones with Vilsmeier-Haack Re- agents using Acetamide and Oxychloride (SOCl2 or POCl3) under conventional (thermal) and non conven- tional [micro...Acetylation and benzoylation reactions of certain aromatic aldehydes, ketones with Vilsmeier-Haack Re- agents using Acetamide and Oxychloride (SOCl2 or POCl3) under conventional (thermal) and non conven- tional [microwave irradiated (MIR), ultrasonic assisted and solvent free mortar pestle (grinding)] conditions. Reactions afforded good to excellent yields of products with both the VH reagents, reaction times were fairly less in the case of [amide/POCl3] than those of [amide/SOCl2] reagent. Reactions are dramatically acceler- ated in under sonicated and microwave irradiations with a trend: MIR (few seconds) >> Sonication (minutes) > Grinding (min) >> thermal (several hrs).展开更多
A simple and regioselective synthesis of 2-chloro-3-formyl-l,8-naphthyridine （1） through V ilsmeier-Haack cyclization of N-（pyridine-2-yl） acetamide has been reported. The reaction of compound （1） with sodium su...A simple and regioselective synthesis of 2-chloro-3-formyl-l,8-naphthyridine （1） through V ilsmeier-Haack cyclization of N-（pyridine-2-yl） acetamide has been reported. The reaction of compound （1） with sodium sulphide gives thione （2） and the reaction of compound （1） with Na2S/DMF followed by reaction with alkyl halide in one pot afforded thioether （3 and 4）. New naphthyridone （5） was synthesized from the action of acetic acid and POCI3 in compound （1）. The condensation of compounds （1 and 8） with hydroxylamine and aniline leads to the formation of compounds （6, 7 and 9）. The 2-chloro-3-formyl-l,8-naphthyridine was treated with sodium azide underwent cyclization to afford tetrazolo （l,5-a） （l,8-naphthyridine-4-carbaldehyde （8）. The azitidinone （10 and 12） and thioazolidinone （11 and 13） were synthesized from shift base intermediates by using chloroacetyl chloride and thioglycolic acid. The formyl group in compound （1） is subjected to cyano （14） and 3-alkoxycarbonyl （15）, respectively. The ester （15） was treated with hydrazine hydrate in ethanol to give acid hydrazide （16） then converted to thio semicarbazide （17） by their reaction with ammonium thiocyanate. New thiadiazolo （18）, triazolo （19） and oxadiazolo （20） have been prepared. The structures of synthesized compounds have been confirmed by suitable spectroscopic techniques such as IR （infrared spectrometry） and ^1H NMR （proton nuclear magnetic resonance）.展开更多
以3,4,5-三甲氧基甲苯(TMT)为原料,先由V ilsm e ier-Haack反应合成6-甲基-2,3,4-三甲氧基苯甲醛,然后在对甲基苯磺酸催化下经Dak in反应将其氧化为6-甲基-2,3,4-三甲氧基苯酚,最后用重铬酸钠催化氧化合成了辅酶Q0,过程总收率达到72.3%...以3,4,5-三甲氧基甲苯(TMT)为原料,先由V ilsm e ier-Haack反应合成6-甲基-2,3,4-三甲氧基苯甲醛,然后在对甲基苯磺酸催化下经Dak in反应将其氧化为6-甲基-2,3,4-三甲氧基苯酚,最后用重铬酸钠催化氧化合成了辅酶Q0,过程总收率达到72.3%。经正交实验得V ilsm e ier-Haack反应的最佳工艺为:n(TMT)∶n(POC l3)∶n(DMF)=1∶1.8∶2.2,反应温度70℃,反应时间7 h。在此工艺条件下,此步反应收率可达93.2%,w(6-甲基-2,3,4-三甲氧基苯甲醛)=98.5%;在Dakin反应中,以w(H2O2)=30%为氧化剂,30℃为最佳反应温度,反应时间1.5 h。展开更多
文摘An environmentally benign and practical preparation method for the Vilsmeier-Haack reagent (VH) has been developed by using phthaloyl dichloride with DMF in toluene or 2-chlorotoluene. Phthalic anhydride as the byproduct was recovered in high yield by simple filtration. Some aromatic acids have been transformed into the corresponding acid chlorides in good yields by employing the isolated VH. Treatment of primary or secondary alcohols with VH gave alkyl formates or alkyl chlorides by depending on the reaction conditions.
基金Project supported by the National Natural Science Foundation of China(No.20572079)the Natural Science Foundation of Zhejiang Province(No.Y407079)the Foundation of Science and Technology Department of Zhejiang Province(No.2007C21116).
文摘Two species of N-arylpyrazoles containing active amino group were synthesized.And formylations of N-arylpyazoles containing amino in different position of pyrazole rings using Vilsmeier-Haack reaction gave a series of useful pyrazole intermediates.The important features of this protocol were cheap materials,easy process,mild reaction conditions and good yield of products.
文摘Acetylation and benzoylation reactions of certain aromatic aldehydes, ketones with Vilsmeier-Haack Re- agents using Acetamide and Oxychloride (SOCl2 or POCl3) under conventional (thermal) and non conven- tional [microwave irradiated (MIR), ultrasonic assisted and solvent free mortar pestle (grinding)] conditions. Reactions afforded good to excellent yields of products with both the VH reagents, reaction times were fairly less in the case of [amide/POCl3] than those of [amide/SOCl2] reagent. Reactions are dramatically acceler- ated in under sonicated and microwave irradiations with a trend: MIR (few seconds) >> Sonication (minutes) > Grinding (min) >> thermal (several hrs).
文摘A simple and regioselective synthesis of 2-chloro-3-formyl-l,8-naphthyridine （1） through V ilsmeier-Haack cyclization of N-（pyridine-2-yl） acetamide has been reported. The reaction of compound （1） with sodium sulphide gives thione （2） and the reaction of compound （1） with Na2S/DMF followed by reaction with alkyl halide in one pot afforded thioether （3 and 4）. New naphthyridone （5） was synthesized from the action of acetic acid and POCI3 in compound （1）. The condensation of compounds （1 and 8） with hydroxylamine and aniline leads to the formation of compounds （6, 7 and 9）. The 2-chloro-3-formyl-l,8-naphthyridine was treated with sodium azide underwent cyclization to afford tetrazolo （l,5-a） （l,8-naphthyridine-4-carbaldehyde （8）. The azitidinone （10 and 12） and thioazolidinone （11 and 13） were synthesized from shift base intermediates by using chloroacetyl chloride and thioglycolic acid. The formyl group in compound （1） is subjected to cyano （14） and 3-alkoxycarbonyl （15）, respectively. The ester （15） was treated with hydrazine hydrate in ethanol to give acid hydrazide （16） then converted to thio semicarbazide （17） by their reaction with ammonium thiocyanate. New thiadiazolo （18）, triazolo （19） and oxadiazolo （20） have been prepared. The structures of synthesized compounds have been confirmed by suitable spectroscopic techniques such as IR （infrared spectrometry） and ^1H NMR （proton nuclear magnetic resonance）.
