四组分一锅法合成多取代吡喃[2,3-c]吡唑-5-腈

在三乙胺催化下,以乙酰乙酸甲酯、苯肼、芳醛和丙二腈等4组分为原料,经一锅法合成了一系列多取代的吡喃并[2,3-c]吡唑衍生物(5a～5j),反应在10～15 min内即可完成.所有产物由IR、1HNMR和MS确证.该方法具有产率高、操作简单等优点.     

碱性离子液体催化“一锅法”合成1,4-二氢吡喃并[2,3-c]吡唑

在碱性离子液体氢氧化1-丁基-3-甲基咪唑([bmim]OH)催化作用下,由芳香醛、丙二腈、苯甲酰乙酸乙酯和肼或苯肼"一锅法"合成了一系列1,4-二氢吡喃并[2,3-c]吡唑化合物.实验中考察了催化剂、反应温度、催化剂用量、溶剂对反应的影响,确定了最优反应条件,给出了可能的反应机理.此外催化剂可以方便地收回,且循环使用四次其催化活性并没有显著降低.目标产物经过了1H NMR,IR,MS和元素分析确证.合成方法条件温和、反应时间短、产率高且对环境友好.     

水介质中吡喃并[3,2-c]吡喃-5-酮衍生物的三组分一锅合成

水介质中在氯化三乙基苄基铵(TEBAC)催化下, 芳醛与丙二腈和4-羟基-6-甲基吡喃-2-酮三组分一锅反应合成了一系列2-氨基-3-氰基-4-芳基-4H,5H-吡喃-5-酮. 该反应具有产率高、污染少、操作简单、环境友好等优点.     

超声作用下四组分一锅法合成二氢吡喃并[2,3-c]吡唑衍生物

报道了在超声波作用下,乙醇作溶剂,无任何催化剂下由醛、水合肼、乙酰乙酸乙酯(或丁酰乙酸乙酯)和丙二腈四组分简单、方便、有效地合成了一系列二氢吡喃并[2,3-c]吡唑衍生物.该方法具有产物产率高、反应时间短、条件温和及操作简单的优点.     

三乙胺功能化聚乙二醇双子离子液体催化合成吡喃并[2,3-c]吡唑

合成了一种三乙胺功能化聚乙二醇双子离子液体,研究了其作为催化剂,在水相中以芳香醛、丙二腈、乙酰乙酸乙酯、水合肼或苯肼为原料的四组分一锅法反应,制备了16种不同取代基的吡喃并[2,3-c]吡唑化合物,产率为86%~94%.该离子液体稳定性高,可以方便的回收,重复使用5次,活性没有明显的下降.该方法具有反应条件温和,操作简单,产物易分离,对环境友好等优点.     

3-甲基-5-氰基-6-氨基-1-苯基-4-(3,4-二甲氧基苯基)-1,4-二氢吡喃[2,3-c]吡唑的合成和晶体结构

标题化合物C22H20N4O3 3是由2-氰基-3-(3,4-二甲氧基苯基)丙烯腈1和3-甲基-1-苯基-2-吡唑-5-酮2在KF-Al2O3催化下在N,N-二甲基甲酰胺(DMF)溶剂中反应而得。结构通过单晶X-射线衍射分析确定,其晶体属于三斜晶系,空间群Pī,a = 9.450(3),b = 10.876(2), c = 11.435(2) ,a = 115.51(1), b = 102.82(1),g = 98.47(2), Mr = 388.42, V = 994.1(3) 3,Dc = 1.298 g/cm3, Z = 2, m (MoKa) = 0.089 mm-1, F(000) = 408。晶体结构用直接法解出,使用全矩阵最小二乘法对原子参数进行修正,最后的偏离因子R = 0.0420,wR = 0.1070。单晶X-射线衍射分析表明平面Ⅰ与平面Ⅱ、平面Ⅲ、平面Ⅳ的夹角分别为102.31、29.24和1.43。平面Ⅱ与平面Ⅲ和平面Ⅳ的夹角分别为73.50和100.91,平面Ⅲ和平面Ⅳ的夹角为27.81, 另外晶体中还存在分子间氢键。     

L-脯氨酸催化一锅法合成4H-吡喃并 2,3-c 吡唑衍生物

以L-脯氨酸为绿色催化剂,3-甲基-5-吡唑酮(或1-苯基取代物)和芳醛及丙二腈为原料,就微波辅助的一锅法成环缩合反应进行研究。实验结果表明,乙醇/水为溶剂,催化剂用量10mol%,微波功率300W和80℃下反应10～15 min,即可得到4H-吡喃并[2,3-c]吡唑类化合物(4a～4j),合成收率达85～94%。该方法具有产率高、反应时间短、操作简单等优点。     

三组分一锅法合成3-甲基-1-苯基-4-芳基-4,11-二氢-4H-吡唑并[4’,5’∶3,2]吡啶并[5,6-c]香豆素

以芳醛、4-羟基香豆素和3-甲基-1-苯基-5-氨基吡唑为原料,用少量冰醋酸作溶剂,三组分一锅法合成一系列吡唑并[4′,5′∶3,2]吡啶并[5,6-c]香豆素衍生物,该反应产率高(79％～94％)、操作简单、后处理方便.产物的结构经红外光谱、核磁共振氢谱、元素分析及单晶X射线分析证实.     

三组分一锅法合成3-甲基-1-苯基-4-芳基-4,11-二氢-4H-吡唑并[4',5':3,2]吡啶并[5,6-c]香豆素

以芳醛、4-羟基香豆素和3-甲基-1-苯基-5-氨基吡唑为原料,用少量冰醋酸作溶剂,三组分一锅法合成一系列吡唑并[4',5':3,2]吡啶并[5,6-c]香豆素衍生物,该反应产率高(79%～94%)、操作简单、后处理方便.产物的结构经红外光谱、核磁共振氢谱、元素分析及单晶X射线分析证实.     

一锅法高效合成氧杂卓并 2,3-c 吡唑类化合物

氧杂卓和吡唑作为优势骨架广泛存在于有生物活性的天然产物和药物分子中。本文探究了碱作用下吡唑类缺电子烯烃与二甲硫醚及4-溴丙烯酸酯一锅法环化反应,考察了碱、溶剂以及物质的量之比对反应收率的影响,并以67%～86%的收率得到系列氧杂卓并[2,3-c]吡唑类化合物,其结构经¹H NMR、¹³C NMR和HR-MS（ESI-TOF）确证。     

Synthesis of Substituted 6-Amino-4-aryl-5-cyano-2H,4H-pyrano[2,3-c]pyrazoles. Crystal and Molecular Structure of 6-Amino-5-cyano-3-methyl-4-(2',4',6'-triethylphenyl)-2H,4H-pyrano[2,3-c]pyrazole

Substituted 6-aminopyrano[2,3-c]pyrazoles were synthesized by the two-component condensation of arylidenemalononitriles and substituted 5-pyrazolones or three-component condensation of aromatic aldehydes, malononitrile, and substituted 5-pyrazolones. It was established by X-ray crystallographic analysis that pyranopyrazoles exist in the 2H and not the 1H tautomeric form.     

Synthesis of 6-Amino-2,4-dihydropyrano[2,3-c]pyrazol-5-carbonitriles Catalyzed by Silica-Supported Tetramethylguanidine Under Solvent-Free Conditions

An efficient, high-yielding, and rapid protocol has been developed for the synthesis of diversity-oriented 6-amino-2,4-dihydropyrano[2,3-c]pyrazol-5-carbonitriles derivatives via a four-component, one-pot cyclocondensation reaction of ethyl acetoacetate, hydrazine hydrate, aldehydes, and malononitrile using silica-supported tetramethylguanidine as a heterogeneous catalyst for the first time. The protocol proves to be efficient and environmentally benign in terms of very easy workup, good yields, and ease of recovery of catalyst. In addition, the present method is superior in terms of green media, the amount of catalyst, and reaction time.     

Pyranopyrazoles. II. Synthesis and reactions of 1H,6H-pyrano[2,3-c]pyrazol-6-ones

Various 1H,6H-pyrano[2,3-c]pyrazol-6-ones (III-XXIII) were obtained from β-keto esters and 1H-pyrazol-5-ones or hydrazines. Nitrations, chlorinations and brominations of these pyranopyrazoles were also carried out giving the corresponding derivatives (XXIV-LXIV). The pyrone ring is the more reactive one in these reactions and the preferred position of attack is the 5-position. The substitution products are formed by the addition-elimination route.     

Synthesis of 1-acyl-5-pyrazolones and pyrrolidino[2,3-c]pyrazol-3-ones

The reactivity of acetamidrazones I in strong basicity conditions was examined. When compounds I are reacted with equivalent quantities of α-haloketones in sodium alcoholate, the pyrrolidino[2,3-c]pyrazol-3-ones IV were obtained by intermediate formation of 1-acyl-3-amino-5-pyrazolones III .     

微波辐射下"一锅煮"法合成2-氨基-3-氰基-4-芳基-4H,5H-吡喃-[3,2-c]苯并吡喃-5-酮

以芳醛、4-羟基香豆素、丙二腈为原料,乙醇为能量转移剂,哌啶为催化剂,在微波辐射下一步合成了一系列2-氨基-3-氰基-4-芳基-4H,5H-吡喃-[3,2-c]苯并吡喃-5-酮,反应在40～60s时间内完成,产率60%～97%.     

One-Pot Synthesis of 2-Amino-5,10-dihydro-5,10-dioxo-4-phenyl-4H-benzo[g]chromene Derivatives Catalyzed by ZnCl2

An efficient one-pot synthesis of 2-amino-5,10-dihydro-5,10-dioxo-4-phenyl-4H-benzo[g]chromene derivatives has been achieved by the reaction of 2-hydroxynaphthalene-1,4-dione, cyanothioacetamide, and aromaticaldehyde in EtOH at room temperature catalyzed by ZnCl₂. The structures of the products were characterized by infrared, ¹H NMR, mass, and elemental analysis.

Simple,Catalyst-Free,One-Pot Procedure for the Synthesis of 2-Amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c]quinolin-5-one Derivatives

A one-pot, three-component reaction of 4-hydroxyquinolin-2(1H)-one, malononitrile, and various aldehydes for the synthesis of 2-amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c]quinolin-5-one derivatives is reported. The reaction is performed without any catalysts in a mixed solvent of water and ethanol to give products in good yields. The present method provided a clean, simple, and economical alternative for the synthesis of potential biologically active pyranoquinoline derivatives.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Organocatalytic One-Pot Asymmetric Synthesis of 4H,5H-Pyrano[2,3-c]pyrazoles

An efficient one pot asymmetric synthesis of tetrahydropyrano[2,3-c]pyrazoles has been developed. This class of biologically active heterocycles can be obtained via a secondary amine catalyzed asymmetric Michael/Wittig/oxa-Michael reaction sequence. Remarkably, the title compounds were accessible in good to very good yields and very good to excellent enantioselectivities after a single purification step.