共查询到19条相似文献,搜索用时 46 毫秒
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研究了芳香醛、乙酰乙酸乙酯和铵盐在水相中的催化Hantzsch反应,探讨了催化剂种类、反应底物比例、反应温度等因素对反应的影响。 最终优化的最佳反应条件为:苯甲醛用量为5 mmol时,0.5 mmol DL-脯氨酸作催化剂,2.5 mmol碳酸铵为氨源,加入10 mL水,于70 ℃条件下反应5 h,收率达90.1%。 催化剂可循环利用,芳香醛底物具有广泛的适用性,产物结构经红外、核磁等技术手段确定。 反应具有环境友好、条件温和、操作简便、产率较高等优点。 结果表明,该水相催化Hantzsch反应具有广泛的适用性。 相似文献
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In the prese of metallic zinc, propargyl bromide is found to react with aldehydes at room temperature in tetrahydrofurane-saturated aqueous ammonium chloride (5:2) to afford the corresponding homopropargylic alcohols in moderate to high yields together with small amounts of α-allenic alchohols. 相似文献
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Aqueous trimethylamine mediated Baylis-Hillman coupling of alkyl acrylates with aldehydes is described. 相似文献
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报道了一种简便、有效的水相噤呐偶合反应。在含有少量季铵盐或季磷盐的氯化铵水溶液中.用金属锌促进羰基化合物进行水相噘呐偶合反应,其中加入的少量季铵盐或季磷盐有助于显著提高反应产率,噘呐醇产率由53%提高到87%。但噘呐偶合反应的产率受羰基周围环境的立体位阻影响较大,在此条件下,金属锌可有效地促进芳香族醛化合物进行水相噘呐偶合反应,得到产率较高的噘呐醇,但非对映异构体选择性差,而脂肪族醛化合物得到的噘呐醇产率较低,在同样条件下,酮类化合物不能顺利进行噘呐偶合反应。 相似文献
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报道了一种简便、有效的水相嚬呐偶合反应。在含有少量季铵盐或季磷盐的氯化铵水溶液中,用金属锌促进羰基化合物进行水相嚬呐偶合反应,其中加入的少量季铵盐或季磷盐有助于显著提高反应产率,嚬呐醇产率由53%提高到87%。但嚬呐偶合反应的产率受羰基周围环境的立体位阻影响较大,在此条件下,金属锌可有效地促进芳香族醛化合物进行水相嚬呐偶合反应,得到产率较高的嚬呐醇,但非对映异构体选择性差,而脂肪族醛化合物得到的嚬呐醇产率较低,在同样条件下,酮类化合物不能顺利进行嚬呐偶合反应。 相似文献
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A simple and effective pinacol coupling of various aromatic aldehydes mediated by gallium in good yields has been carried out. The reaction is highly effective in water in the prurience of KOH or HCl and was strongly affected by the steric environ-ment surrounding the carbonyl group. Aliphaflc aldehydes, ke-tones and aromatic ketones appear inert under the same reac-tion conditions. 相似文献
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Homoallylic alcohols can be obtained from allylation of aldehydes and ketones with allyl bromide promoted by metallic lead. These reactions can be carried out smoothly in aqueous media. 相似文献
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Pinacol coupling of aromatic aldehydes by aqueous vanadium(II) solution under ultrasound irradiation at room temperature can lead to the corresponding pinacols in 54–93% yields within 15–30 min. 相似文献
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α-Haloketone reacted with aldehydes to form α, β-unsaturated ketones accompanied by dehalogenation in the presence of SmI2. Mechanism involving samarium enolate intermediate formed in situ from α-haloketone with both SmI2 and Sm(III)/I species was proposed. 相似文献