Regioselective synthesis of pentacyclic heterocycles by sequential [3,3] sigmatropic rearrangement of 2-(4′-aryloxybut-2′-ynyl-mercapto)thiochromen-4-ones

A number of 4-aryloxymethyl-7-chlorothiopyrano[2,3-b]thiochromen-5(2H)-ones are regioselectively synthesized in 80-85% yield by the Claisen rearrangement of 2-(4′-aryloxybut-2′-ynylmercapto)thiochromen-4-ones in refluxing chlorobenzene for 3 h. These products are then subjected to a second Claisen rearrangement in refluxing N,N-diethylaniline for 6 h to give hitherto unreported pentacyclic heterocycles in 50-55% yield.     

微波促进下6-氨基-4-芳基-5-氰基-3-甲基-1-苯基吡啶[2,3-c]并吡唑的合成

5-氨基-3-甲基-1-苯基吡唑与芳亚甲基丙二腈在少量乙二醇中, 经微波辐射得到6-氨基-4-芳基-5-氰基-3-甲基-1-苯基吡啶[2,3-c]并吡唑衍生物, 反应4～8 min完成, 产率为71%～90%, 产物结构通过红外、核磁共振、元素分析及单晶X射线分析表征.     

金属氯化物对硼氢化钠还原α-氯代苯乙酮的影响

以芳醛、麦氏酸和3-甲基-1-苯基-5-氨基吡唑为原料, 经微波辐射一步得到4-芳基-3-甲基-6-氧代-1-苯基-4,5,6,7-四氢吡啶并[2,3-c]吡唑衍生物, 反应2～6 min完成, 产率高. 产物结构通过红外、核磁共振、元素分析及单晶X射线分析确证.     

Condensed Pyridine Bases. Synthesis and Reactions of Benzofuro[2,3-c]indeno[2,1-e]-, Benzothieno[2,3-c]Indeno[2,1-e]-, Benzofuro-[3,2-c]Indeno[2,1-e]- and Thieno[2,3:4′,5′]-thieno[3,2-c]indeno[2,1-e]pyridines

Condensation of hetarene carboxaldehydes with phthalide gave 2-(3-hydroxy-1-oxoinden-2-yl)benzo[b]furan and 2-(3-hydroxy-1-oxoinden-2-yl)-5-ethylthieno[2,3-b]thiophene. Starting from hetaryl acetic acids gave 3-(3-hydroxy-1-oxoinden-2-yl)benzo[b]furan and 3-(3-hydroxy-1-oxoinden-2-yl)benzo[b]thiophene. Acylation of 3-hydroxy-1-oxoinden-2-yl-substituted heterocycles using acetic anhydride in the presence of 70% HClO₄ leads to the formation of pentacyclic pyrilium salts. Pentacyclic indenopyridines are prepared by treating the pyrilium salts with ammonia. The reaction of the carbonyl group in the indenopyridines with hydroxylamine, hydrazine hydrate, and in reduction using NaBH₄ has been studied.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 435–443, March, 2005.     

新型环烷烯并嘧啶并噻唑-3-酮类化合物的合成

以环戊酮、环庚酮为起始原料合成的环烷烯并[1,2-d]嘧啶-2-硫酮(2)与氯乙酸、芳香醛反应, 合成具有潜在抗癌活性的稠合杂环化合物5-芳基-2,8-二芳亚甲基-2,3,6,7-四氢-5H,8H-环戊烯并[1,2-d]噻唑并[3,2-a]嘧啶-3-酮(3)以及5-芳基-2,10-二芳亚甲基-2,3,6,7,8,9-六氢-5H,10H-环庚烯并[1,2-d]噻唑并[3,2-a]嘧啶-3-酮(4). 3和4的结构经¹H NMR, IR, MS分析确认.     

Ring expansion of trans-divinyl ethylene oxide by oxonium ylide [2,3] sigmatropic rearrangement

Oxonium ylide [2,3] sigmatropic rearrangement of trans-divinyl ethylene oxide is observed upon its exposure to ethyl or t-butyl diazoacetate in the presence of either Rh(II) or Cu(II) catalysts to produce cis-6-vinyl-3,6-dihydropyran-2-carboxylates.     

Efficient synthesis of 2- and 3-substituted-2,3-dihydro [1,4]dioxino[2,3-b]pyridine derivatives

A versatile new approach for the synthesis in three steps of 2-substituted-2,3-dihydro[1,4]dioxino[2,3-b]pyridines B via a Smiles rearrangement using easily available reagents is described. A study illustrating the influence of experimental conditions on the progress of the reaction is reported.     

Palladium-mediated synthesis of 5-substituted 4-alkynylthieno[2,3-c]pyran-7-ones

We describe here, the first palladium-mediated tandem C-C bond forming reaction between 3-iodothiophene-2-carboxylic acid and terminal alkynes to afford the unexpected 5-substituted 4-alkynylthieno[2,3-c]pyran-7-ones in good yields.     

苯并吡喃[3,4-c]吡啶-5-酮类化合物的合成

以4-酮-3-甲酸甲酯哌啶盐酸盐为原料, 通过分子间环加成和N-烷基化反应, 合成了一系列潜在的多巴胺D₄受体配基苯并吡喃[3,4-c]吡啶-5-酮类化合物, 并用¹H NMR, IR, ESI-MS, 元素分析对其进行了表征.     

Some chemical properties of 2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-one and 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones

We have studied the reaction of 2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-one and 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones with amines, alkylating reagents, and hydrogen peroxide. We have shown that the presence of an aryl substituent at the 2 position of [1,3-thiazino[3,2-a]benzimidazol-4-ones has a substantial effect on the direction of the reactions. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 445–452, March, 2006.     

Studies on the [2,3]-Stevens rearrangement of aziridinium ions

The aziridinium ylide generated by the intramolecular reaction of a metal carbenoid tethered to a vinylaziridine undergoes [2,3]-Stevens rearrangement to furnish the indolizidine skeleton. It is essential that the correct nitrogen invertomer is used or a competing [1,5]-hydrogen shift predominates. During the preparation of a second system a `one-pot' acylation-[3,3]-Claisen rearrangement was observed, delivering a seven-membered lactam.     

Lewis acid mediated [2,3]-sigmatropic rearrangement of allylic ammonium ylides

An investigation of the Lewis acid mediated [2,3]-sigmatropic rearrangement of allylic ammonium ylides has been conducted by employing various bases and boron Lewis acids. Using BBr₃ together with the phosphazene base 6, various allylic amines could be rearranged in good yields with low to excellent diastereoselectivity.     

A NOVEL SYNTHESIS OF 2-SUBSTITUTED-4H-THIENO [2,3-d][1,3] OXAZIN-4-ONE AND 2,3-DISUBSTITUTED THIENO [2,3-d]PYRIMIDIN-4(3H)-ONE DERIVATIVES

Abstract

The synthesis of acetic 2-{[1-methyl-2-(4-oxo-5,6,7,8-tetrahydro-4H-benzo [4,5]-thieno [2,3-d] [1,3-oxazin-2-yl)ethylidene]amino}-4,5,6,7-tetrahydrohenzo[b]thiophene ?3-carboxylic acid anhydride 5 and 2-(oxopropyl)-5,6,7,8-tetrahydro-4H-benzo-[4,5] thieno[2,3-d][1,3]oxazin-4-one 7, has been achieved in three steps from ethyl 2-amino-4,5,6,7-tetrahydrobenzo(b]thiophene-3-carboxlate 1 via the reaction with ethyl acetoacetate followed by hydrolysis and acetic anhydride-induced cyclization. The 2-substituent in compound 5 has two functional groups i.e. active methylene and acid anhydride which are suitably located for intramolecular transformation. Thermal and/or base catalyzed intramolecular cyclization of 5 afforded 2-(4-acetoxy-(hydroxyl)-2-methyl-5,6,7,8-tetrahydrobenzo[4,5] thieno[2,3-b]pyridin-3-yl)-5,6,7,8- tetrahydro-4H-benzo[4,5]thieno[2,3-d] [1,3]oxazin-4-one 10 and 9 respectively. Treatment of 5 with hydrazine hydrate, aromatic and/or heterocyclic amines induced the same intramolecular cyclization with a concomitant oxazine-pyrimidine interconversion to give 3-amino(aryl or heteryl)-2-(4-hydroxy-5,6,7,8-tetrdhydrobenzo-[4,5]thieno[2,3-b]pyridin-3-yl)-3,4,5,6,7,8-hexahydrobenzo[4,5] thieno[2,3-d] pyrimid in-4-one 11–14 respectively.     

Catalyst-free synthesis of novel 4H-indeno[1,2-b]furan-4-ones and furo[2,3-d]pyrimidines in water

An operationally simple, catalyst-free, and efficient protocol for the synthesis of novel 4H-indeno[1,2-b]furan-4-one and furo[2,3-d]pyrimidine derivatives by a one-pot reaction of 2-aminopyridines, 1,3-indandione, or barbituric acid and phenylglyoxal monohydrate in water at reflux, involving domino aldol condensation, Michael addition, and ring-closing reactions is described. This transformation has several advantages, including high yield, short reaction duration, simple workup, and simple purification.     

Reaction of 6-glycopyranosylaminopyrimidin-4-ones with malonic acids. Synthesis of 8-glycopyranosylpyrido[2,3-d]pyrimidin-4-one derivatives

Summary Reactions of 6-glycopyranosylaminopyrimidin-4-ones1 a–d with malonic, methyl malonic and ethyl malonic acids are discussed in this paper. These reactions have been carried out in acetic anhydride at 100°C affording the 8-glycopyranosylpyrido[2,3-d]pyrimidin-4-ones2 a–d,3 c–d and the 5-acyl-6-glycopyranosylaminopyrimidin-6-ones4 a–d,5 a–d.

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Reaktion von 6-Glycopyranosylaminopyrimidin-4-onen mit Malonsäuren. Synthese von 8-Glycopyranosylpyrido[2,3-d]pyrimidin-4-on-Dervaten

Zusammenfassung Es werden Reaktionen der 6-Glycopyranosylaminopyrimidin-4-one1 a–d mit Malonsäure, Methylmalonsäure und Ethylmalonsäure diskutiert. Die Reaktionen wurden in Essigsäureanhydrid bei 100°C ausgeführt und ergaben 8-Glycopyranosylpyrido[2,3-d]pyrimidin-4-one2 a–d,3 c–d und die 5-Acyl-6-glycopyranosylaminopyrimidin-6-one4 a–d und5 a–d.

     

Total synthesis of (3S,4S,2′S)- and (3R,4R,2′S)-viridiofungin A triester

The total synthesis of an alkylcitrate secondary metabolite from the fungi Trichoderma viride is described. An ester dienolate [2,3]-Wittig rearrangement and a S. Julia-Kocienski olefination served as key C/C-connecting transformations. The highly convergent synthesis consists of a longest linear sequence of 17 steps.     

KF/Al2O3催化下2-氨基-4-芳基-4H-吡喃并[3,2-c]香豆素衍生物的一步合成

以芳醛、4-羟基香豆素和丙二腈或氰乙酸酯为原料, 在KF/Al₂O₃催化下以乙醇为溶剂, 在80 ℃合成了一系列2-氨基-4-芳基-4H-吡喃并[3,2-c]香豆素衍生物, 并通过IR, ¹H NMR和元素分析确证产物的结构.