Vinyltriphenylphosphonium Salt Mediated One-Pot Stereoselective Synthesis of Dialkyl ( E )-2-(2-methyl-5-oxo-1-cyclopentenyl)-2-butenedioates

Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by 2-hydroxy-3-methyl-2-cyclopenten-1-one leads to vinyltriphenylphosphonium salts, which undergo an intramolecular Wittig reaction to produce the corresponding cyclobutene derivatives. The cyclobutene derivatives are not isolable and undergo electrocyclic ring-opening reactions in CH 2 Cl 2 at room temperature to produce dialkyl ( E )-2-(2-methyl-5-oxo-1-cyclopentenyl)-2-butenedioates in moderate yields.     

Vinylphosphonium Salt Mediated Facile Synthesis of Trialkyl 4-(2-Quinolyl)-1-cyclobutene-1,2,3-tricarboxylates and Dialkyl 3-Ethoxy-4-oxo-5-(2-(1H)-quinolinylidene)-2-cyclopentene-1,2-dicarboxylates

Summary.  The reactive 1:1 intermediate produced in the reaction between dialkyl acetylenedicarboxylates and triphenylphosphine was trapped by ethyl 3-(1,2-dihydroquinoline-2-ylidene)-pyruvate to yield the isomeric dialkyl 3-ethoxy-4-oxo-5-(2-(1H)-quinolinylidene)-2-cyclopentene-1,2-dicarboxylates and trialkyl 4-(2-quinolyl)-1-cyclobutene-1,2,3-tricarboxylates in nearly 4:1 ratio. Received April 3, 2001. Accepted (revised) May 22, 2001     

Silica Gel Catalyzed Stereoselective Conversion of Dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates to Dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in Solvent-Free Conditions

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 1-hydroxy-2-acetonaphthone leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates. Silica gel was found to catalyze conversion of dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates to dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in solvent-free conditions at 90°;C in fairly good yields.     

Introduction of a Novel Reaction of Triacetylmethane: One-Pot Synthesis of Dialkyl-2-(3,1-hydroxyethylidene-2,4-pentanedione-3-yl)-3-(triphenylphosphoranylidene)-butanedioate

Protonation of reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylate by 3-(1-hydroxyethylidene)-2,4-pentanedione leads to vinyl phosphonium salts, which undergo Michael addition with the conjugate base of CH-acid to produce the title compounds in high yield.     

Stereoselective synthesis of dialkyl 3-spiroindanedione-1,2,3,3a-tetrahydropyrrolo[1,2-a]quinoline-1,2-dicarboxylates

The 1:1 intermediate generated by the addition of quinoline to dialkyl acetylenedicarboxylates is trapped by 1,3-indanedione to yield dialkyl 3-spiroindanedione-1,2,3,3a-tetrahydropyrrolo[1,2-a]quinoline-1,2-dicarboxylates in good yields. The structures of these products were confirmed by NMR and single-crystal X-ray diffraction studies.     

Synthesis of 2,3,3a,8 a-tetrahydrofuro[2,3-b] benzofuran-2-one from coumarin

4-Vinyl-3,4-dihydrocoumarin, which is obtained in two steps from 3-(2-benzyloxyphenyl)allyl alcohol, was converted to 2,2,3a,8a-tetrahydrofuro[2,3-b]benzofuran-2-one by oxidation and rearrangement.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 748–750, June, 1976.     

Synthesis and some chemical properties of 8-methyl-3-hydroxy-6-oxo-2H-3,4,5,6-tetrahydropyrimido [2,1-b][l,3]thiazines

Conclusions Pyrimidothiazines are converted to the corresponding 3-(thiiranyl-2'-methyl)-6-methyl-uracils on heating (170–200°C) in organic solvents.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1634–1636, July, 1986.     

Synthesis of heterocycles on the basis of iminotetrahydrocarbazoles. 1. 3-Benzyl-8-methyl-2-oxo-2,3,3a,4,5,6-hexahydro-1H-pyrazino[3,2,1-j,k]-carbazole

The reaction of 6-methyl-1-oxo-1,2,3,4-tetrahydrocarbazole and benzylamine gave 1-benzylimino-6-methyl-1,2,3,4-tetrahydrocarbazole, which was converted by two methods to a pyrazinocarbazole derivative. The promising character of the use of iminotetrahydrocarbazoles for the synthesis of more complex heterocyclic systems was thereby demonstrated.Translated from Khimiya Geterosiklicheskikh Soedinenii, No. 12, pp. 1632–1635, December, 1987.The authors thank L. M. Alekseeva for investigating the PMR spectra and N. M. Rubtsov and V. V. Chistyakov for investigating the IR and mass spectra.     

One-Pot Stereoselective Synthesis of Alkyl Z-2-[2-Amino-4-oxo-1,3-selenazol-5(4H)-yliden] Acetates

Abstract

Selenourea reacts with dialkyl acetylenedicarboxylates in acetone to form 1:1 adducts, which undergo a cyclization reaction to produce alkyl Z-2-(2-amino-4-oxo-1,3-selenazol-5(4H)-yliden) acetates in fairly good yields. The reaction is completely stereoselective.     

DABCO-catalyzed multi-component domino reactions for green and efficient synthesis of novel 3-oxo-3H-benzo[a]pyrano[2, 3-c] phenazine-1-carboxylate and 3-(5-hydroxybenzo[a]phenazin-6-yl) acrylate derivatives in water

An efficient, convenient and environmentally benign procedure for the synthesis of novel 3-oxo-3H-benzo[a]pyrano[2,3-c]phenazine-1-carboxylate and 3-(5-hydroxybenzo[a]phenazin-6-yl)acrylate derivatives has been developed by domino three-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines and acetylenic esters in the presence of a catalytic amount of DABCO as an expedient, eco-friendly and reusable base catalyst in water. This green process produces biologically and pharmacologically significant heterocycles in a one-pot single operation and offers considerable advantages such as:operational simplicity, short reaction time, high yields, reusability of catalyst, absence of any tedious workup or purification and avoids hazardous reagents/solvents.     

4-Hydroxy-2-quinolones 120. Synthesis and structure of ethyl 2-hydroxy-4-oxo-4H-pyrido-[1,2-a]pyrimidine-3-carboxylate

An improved method for the preparation and purification of ethyl 2-hydroxy-4-oxo-4H-pyrido[1,2-a]-pyrimidine-3-carboxylates is proposed. According to ¹H and ¹³C NMR spectroscopic data the synthesized compounds exist in DMSO solution in the 2-hydroxy-4-oxo form while in the crystal (at least for the case of the unsubstituted derivative) X-ray analysis shows that it occurs in the bipolar 2,4-dioxo form. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 864–876, June, 2007.     

Iodine-Catalyzed,Rapid and Efficient,One-Pot Synthesis of 1,2-Dihydro-1-arylnaphtho[1,2e][1,3]oxazine-3-ones Under Solvent-Free Conditions

A mixture of β-naphthol, araldehydes, and urea in the presence of a catalytic amount of iodine as catalyst under solvent-free condition was heated for 5 min on a preheated hot plate to get the corresponding 1,2-dihydro-1-aryl-naphtho[1,2-e][1,3]oxazine-3-ones in very good yield.     

Synthesis of 5-amino-3a,4-dicyano-2,3,3a,6a-tetrahydrofuro[2,3-b]pyrroles

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, p. 282, February, 1992.     

Stereoselective Synthesis of syn-and anti-3a-Hydroxyl-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b] indole-2-carboxylic Acid

The structure of syn-and anti-N^b-(p-toluenesulfonyl)-3a-hydroxyl-1,2,3,3a,8,8a-hexahydro pyrrolo[2,3,-b]indole-2-carboxylic t-butyl ester was stercoselectively synthesized by oxidative ring formation of N^b-(p-toluenesulfonyl)-L-tryptophan t-butyl ester in methylene chloride containing dimethyldioxirane(DMDO),the p-toluenesulfonly group and t-butyl group can be easily removed by sodium naphthalenide and trifluoroacetic acid,respectively.     

3,4-二氢-3-甲基-4-氧代咪唑[5,1-d]并[1,2,3,5]四嗪-8-甲酸苯磺酰基呋咱氮氧基酯的合成

以3,4-二氢-3-甲基-4-氧代咪唑[5,1-d]并[1,2,3,5]四嗪-8-甲酰胺和苯磺酰基呋咱氮氧化物为原料,通过肖滕-鲍曼法合成了5种新的咪唑四嗪衍生物——3,4-二氢-3-甲基-4-氧代咪唑[5,1-d]并[1,2,3,5]四嗪-8-甲酸苯磺酰基呋咱氮氧基酯,其结构经1H NMR,IR,MS和元素分析确证。     

Heterocycles. Part XVII. Synthesis of new substituted 2,3,3a,4,5,6-hexahydrobenzo[6,7]cyclohepta[1,2-c]pyrazoles and related compounds

Aryl aldehydes I reacted with 1-benzosuberone to yield the corresponding 2-arylidene-1-benzosuberones II . Condensation of II with hydrazine and its derivatives provided the substituted 2,3,3a,4,5,6-hexahydro-benzo[6,7]cyclohepta[1,2-c]pyrazoles III-VI respectively. The structures of all products were assigned by chemical and spectroscopic methods.     

Addition compounds of nucleophiles and 3-ethylthio-6-oxo-6H-1,2-dithiolo[4,3-c]1,2-dithiolium tetrafluoroborate. Synthesis of 3H,6H-1,2-dithiolo[4,3-c]1,2-dithiole-3-one-6-thione

Summary A smooth method of synthesizing 3H, 6H-1,2-dithiolo[4,3-c]1,2-dithiole-3,6-dithione (3), and also its partial desulfuration to yield 3H, 6H-1,2-dithiolo[4,3-c]1,2-dithiole-3-one-6-thione (4) is presented. The ethylation product5 of the monothione4 reacts with various nucleophilic reagents to form remarkably stable adducts. The adducts of5 with methanol,tert-butyl mercaptan, and with aniline could be isolated and characterized by their¹H-NMR spectra.

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Anlagerungsverbindungen von Nukleophilen an 3-Ethylthio-6-oxo-6H-1,2-dithiolo[4,3-c]1,2-dithioliumtetrafluoroborat. Synthese von 3H,6H-1,2-Dithiolo[4,3-c]1,2-dithiol-3-on-6-thion

Zusammenfassung Eine glatte Synthese für 3H,6H-1,2-Dithiolo[4,3-c]1,2-dithiol-3,6-dithion (3) und für dessen partielle Entschwefelung zu 3H,6H-1,2-Dithiolo[4,3-c]1,2-dithiol-3-on-6-thion (4) wird angegeben. Das Ethylierungsprodukt5 des Monothions4 reagiert mit unterschiedlichen Nukleophilen zu bemerkenswert stabilen Addukten. Die Addukte mit Methanol,tert.-Butylmercaptan und mit Anilin wurden isoliert und durch ihr¹H-NMR-Spektrum charakterisiert.

     

2, 3-二氯-5-取代-5, 8-二氢-8-氧-吡啶并[2, 3-b)吡嗪-7-羧酸乙酯的合成

3, 5, 6-哌嗪三酮-2-甲酰胺(5)经与PCl5-POCl3反应制得3, 5, 6-三氯-2-氰基吡嗪(6)。6经转化为甲酯(7)再水解为3, 5, 6-三氯-2-吡嗪甲酸(8)。由8出发合成了两个2, 3-二氯-5-取代-5, 8-二氢-8-氧-吡啶并[2, 3-b]吡嗪-7-羧酸乙酯(11a~b)。其中5, 7~11均为新化合物, 其组成和结构经元素分析、IR、^1H NMR、MS证实。     

Synthesis of 3-Trifluoromethyl-Substituted Benzo[f]chromene Derivatives in a One-Pot Reaction

In the presence of 1,8-diazabicycolo[5.4.0]undec-7-ene (DBU) and concentrated H₂SO₄, 2-naphthol reacted smoothly with α,β-unsaturated trifluoromethyl ketones in CH₂Cl₂ at room temperature, affording the 3-trifluoromethyl-substituted benzo[f]chromene derivatives in good to excellent yields in a one-pot reaction.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details].