Letters in Organic Chemistry - Volume 10, Issue 9, 2013

Addition reaction of tertiary amines to dimethyl acetylenedicarboxylate mediated by molecular iodine is described. The trialkylamines afford dealkylative adducts in moderate to good yields. Amines containing an aryl group react sluggishly in low yields with a loss of alkyl group.

A convenient one-pot synthetic method is described for the synthesis of symmetrical diaryl sulfides via CuIcatalyzed cross-coupling reactions of various aryl halides and thiosemicarbazide (thiourea) in the presence of KF/Al2O3.

Cyclization of the (4S)-PhCH2OCONHCH(CH2OH)CONHN=CH-aryl, obtained in 4 steps from L-serine, on treatment with MeI and potassium carbonate, generates the chiral oxazolidinones, (4S)-N'-[(E)-(phenyl)methylidene]-Nmethyl- 2-oxo-1,3-oxazolidine-4-carbohydrazides. Overall the formation of the (4S)-N'-[(E)-(phenyl)methylidene]-Nmethyl- 2-oxo-1,3-oxazolidine-4-carbohydrazides from L-serine occurs with retentio Read More

We describe the synthesis of the novel 2-(1,5-dimethyl-4-oxo-hexyl)-3-hydroxy-5-methyl-6-pyrrolyl-1,4- benzoquinone 2 from the natural product perezone 1. The anion–guest properties of the new compound were evaluated in the presence of fluoride, chloride, bromide and iodide tetrabutylammonium salts using 1H NMR titration techniques in deuterated dichloromethane or dimethylformamide. The title compound Read More

Isoxazole is a five membered heterocyclic compound having various pharmacological actions. The new practical synthesis of isoxazole from the easily available malonadehyde tetraethyl acetal by avoiding the use of toxic reagent such as cadmium chloride under environment friendly conditions has been developed.

5-Chloro-7-(2-phenylethynyl)quinolin-8-ol and 7-iodo-5-(2 -phenylethynyl)quinolin-8-ol was synthesized by Pd-CuI catalyzed Sonogashira-type cross-coupling of 8-(benzyloxy)-5-chloro-7-iodoquinoline and 8-(benzyloxy)-5,7- diiodoquinoline with 1-ethynylbenzene. The coupling products were smoothly debenzylated by boron trichloride in dichloromethane to afford the corresponding products in good yields.

One-pot synthesis of 2-azetidinones has efficiently been carried out in excellent yields by treatment of imines and substituted acetic acids with 3,5-dinitrobenzoyl chloride in the presence of triethylamine. The method is remarkably convenient and pure products were obtained by simple crystallization.

5-benzoyl-4-aryl-6-phenyl-1,2,3,4-tetrahydro-2-thioxopyrimidines were synthesized via Biginelli cyclocondensation reaction. The diethyl 2-(4-aryl-5-benzoyl-6-phenyl-3,4-dihydropyrimidin-2(1H)-ylidene) malonates were prepared by the reaction of thioxopyrimidines with diethyl 2-bromomalonate in dioxane/pyridine (10/1 v:v) under microwave irradiation and conventional conditions. The reaction of diethyl 2-(5-benzoyl-4,6-phenyl-3 Read More

Anatase phase TiO2- nanoparticles (TiO2 NPs) used as a heterogeneous and highly efficient catalyst for the synthesis of formamides and acetamides by reacting the structurally diverse amines with formic acid and acetic anhydride or acetic acid, respectively, under solvent-free conditions at room temperature. Chemoselectivity, mild and heterogeneous conditions, clean work-up and high reaction yields make thi Read More

The routes of synthesis of the new boron nucleosides – 3’,5’-cyclic boron esters of 2’-deoxycytidine, 2’- deoxyuridine and thymidine along with 3’,5’-bis(pinacolborate) derivatives of 2’-deoxyuridine, 5-fluoro-2’-deoxyuridine and thymidine are presented. The 1H-, 13C- and 11B NMR data of new boron nucleosides are compared with their precursors NMR properties. Presented compounds are in fact boron analogs of nucleotides Read More

The direct arylation of azoles with arylboronic acids is effectively promoted by PdCl2 in the presence of copper and iron salts under ligand and base-free conditions. This reaction can be applied to heterocycles such as benzothiazole, benzoxazole, 1-methylbenzimidazole and 4,5-dimethylthiazole with moderate to good yields.

A series of 24 novel triazole-linked flavonol glycoconjugates 1~24 were synthesized using flavonols (Kaempferol, Rhamnocitrin or 7,5,4’-trimethoxy flavonol) and carbohydrates (glucose, galactose, lactose or maltose) as starting materials by a “Click chemistry” approach. Intermolecular Cu (I) catalyzed 1,3-dipolar cycloaddition of propargyl ethers of flavonols and glycosyl azides is the key step. Their cytotoxic potential against f Read More

Boron trifluoride supported on hydroxyapatite nanorods efficiently catalyzed the ring opening reaction of α- epoxyketones in methanol solution to afford the corresponding α-hydroxy-β-methoxyketones through Cβ –O bond cleavage in excellent yields at room temperature. The type and position of the additional substituent affect not only the rate of ring opening but also the diastereomeric ratios products.

The 5-alkylthio and 5-arylthiotetrazoles were efficiently synthesized from thiocyanates using Fe3O4 nanoparticles as a magnetically recoverable and reusable catalyst. The main advantages allocated to this method are elimination of hydrazoic acid as a dangerous and harmful reagent, high yields and ease of product isolation. The catalyst can be simply recovered by an external magnet and reused with no significant loss in its reactivity.