Cecilio Alvarez-Toledano

Infrared-assisted eco-friendly selective synthesis of diindolylmethanes

An alternative and environmentally benign pathway for selective synthesis of aryl-3,3′-diindolylmethanes from indole and several aromatic aldehydes is described. The electrophilic aromatic substitution (EAS) reactions are achieved with good yield and short reaction time employing infrared irradiation as energy source and a bentonitic clay as catalyst and reaction medium, in solvent-free reaction conditions.

Dimethyltin(IV) 2,6-disubstituted pyridine complexes

Abstract The synthesis and characterization of hypervalent pentacoordinated dimethyltin complexes obtained from the reaction of 2,6-disubstituted pyridine ligands with dichlorodimethyltin are reported. The complexes were characterized by mass spectrometry, 1H-, 13C- and 119Sn-NMR and Mossbauer spectroscopy, additionally the structures for two compounds were established by X-ray diffraction analysis. The structural parameters indicated pentacoordinated structures, which present Sn–N interaction and trigonal bipyramidal tin environment.

Heteronuclear (WFe) and homonuclear (FeFE) μ-alkylidene complexes of transition metals from mononuclear terminal carbene complexes. crystal structures of {WFe[μ-η1, η3-C(OCH2CH3)(CHCHCH3](CO)8} and [fe2{μ-η2,η3-C[OCH2CH3[CHC(OCH2CH3)(CH3]}(CO)6

Abstract The reactions of mononuclear carbene complexes of W and Fe of the type CO) m MC(OR)(CH 2 n CHCR′″ (M  = FE, W; m = 4 and 5; n = 0, 2, 3; R′, R″ = C, CH 3 , OEt) with Fe(CO) 5 have been studied. In all cases the reaction leads to new hetero (WFe) or homo (FeFe) μ-alkylidene complexes, the position of the double bond depending strongly on n .

Reactivity of Fe3(CO)12 towards thiols containing an α,β-unsaturated ketone system

Abstract The unsaturated derivatives [Fe 2 (CO) 6 (μ-S 2 CCHC(O)C 6 H 4 X)] (X=F, OMe) have been isolated by reaction of [(HS) 2 CCHC(O)C 6 H 4 X] (X=F, OMe) with Fe 3 (CO) 12 in dried THF. Addition of Fe 2 (CO) 9 to a solution of [Fe 2 (CO) 6 (μ-S 2 CCHC(O)C 6 H 4 OMe)] affords [Fe(CO) 4 {μ-(OMe)C 6 H 4 C(O)CHC(S) 2 Fe 2 (CO) 6 }]. The new compounds have been characterised by analytical and spectroscopic data and the crystal structure of [Fe 2 (CO) 6 (μ-S 2 CCHC(O)C 6 H 4 F)] has been solved by X-ray diffraction.

Green Approach—Multicomponent Production of Boron—Containing Hantzsch and Biginelli Esters

Multicomponent reactions are excellent methods that meet the requirements of green chemistry, by reducing the number of steps, and consequently reducing purification requirements. Accordingly, in this work, 11 novel hybrid-boron-containing molecules, namely eight 1,4-dihydropyridines and three 3,4-dihydropyrimidinones, derived from formylphenylboronic acids (ortho, meta and para), were obtained using a green approach, involving H-4CR and B-3CR practices, in the presence of ethanol, which is a green solvent, and using three comparatively different modes of activation (mantle heating, yield 3%–7% in 24 h, Infrared Radiation (IR) irradiation, yield 12%–17% in 12 h, and microwave irradiation, yield 18%–80%, requiring very low reaction times of 0.25–0.33 h). In addition, as a green-approach is offered, a convenient analysis, of the 12 green chemistry principles for the overall procedure was performed. Finally, since all the products are new, characterizations were carried out using common analytic procedures (1H, 11B, and 13C NMR, FAB+MS, HRMS, and IR). The accurate mass data of unexpected ions related to interactions between thioglycerol and the expected products, in the FAB+-mode, enabled unequivocal characterization of the target molecules.

Formation and X-ray structure of the μ-alkylidene complex Fe2(CO)6(μ−η3, η3−C(CH = CHPh)2) upon deoxygenation of Fe2(CO)8(μ−η2, η2−C(O)(CH = CHPh)2) with methyl lithium

Abstract Di-iron nonacarbonyl reacts with dibenzylideneacetone (5) to produce, depending on the reaction conditions, either a mixture of the three complexes Fe(CO)4[η2(CO)(CH = CHPh)2] (6), Fe2(CO)8[η2, η2(CO)(CH = CHPh)2] (7), and Fe(CO)3[η4(CO)(CH = CHPh)2] (8), or solely complex 7 in which the ligand is bound in a η2, μ−gh2, η2 or η4 fashion. All three complexes have been fully characterized by X-ray crystallography. Crystal data for complex 6: C21H14FeO5, monoclinic, space group P2 1 / n , a = 6.326(2) A , b = 14.567(2) A , c = 20.504(2) A , β = 96.91(2) 0 , U = 1875(4) A 3 , D c = 1.422 g cm −3 , Z = 4 . For complex 7: C25H14Fe2O9, triclinic, space group P 1, a = 9.677(5) A , b = 10.635(5) A , c = 13.471(6) A , α = 104.24(3) 0 , β = 105.46(4) 0 , γ = 104.75(4) 0 , U = 1216.7(8) A 3 , Dc = 1.56 g cm−3, Z = 2. For complex 8: C20H14FeO4, orthorhombic, space group P bca , a = 13.397(2) A , b = 10.041(3) A , c = 26.579(2) A , U = 3575.1(8) A 3 , D c = 1.39 g cm −3 , Z = 8 . Upon reaction with MeLi under an atmosphere of CO, all of the three complexes each gave a mixture of the expected η4-ketene complex Fe(CO)4(η4-PhCH = CH(C = C = O)CH = CHPh) (9) as the result of a deoxygenation-carbonylation reaction, and the new μ-alkylidene complex Fe2(CO)6(μ−η3, η3-C(CH = CHPh)2) (10) as the result of a deoxygenation reaction of the starting complex followed by the trapping of the intermediate alkylidene complex by Fe(CO)3. Complex 10, C23H14Fe2O6, has been fully characterized by X-ray crystallography and shown to be orthorhombic, space group P bcn , a = 17.155(4) A , b = 7.842(2) A , c = 15.857(2) A , U = 2133.2(5) A 3 , D c = 1.55 g cm −3 , Z = 4 .

Multinuclear NMR and X-ray diffraction study of pentacoordinated siloxane structures derived of pyridine diols

Abstract Synthesis and characterization of hypervalent pentacoordinated organosilicon complexes obtained from the reaction of disubstituted pyridine ligands with dichlorodiphenylsilane, dichloromethylphenylsilane and bis(dimethylamino)dimethylsilane are reported. The monomeric complexes obtained were characterized by mass spectrometry and multinuclear NMR spectroscopy; additionally their structures were established by X-ray diffraction analysis. The structural parameters indicated Si–N interaction with pentacoordinated geometries displaced towards trigonal bipyramid (TBP); the 29 Si-NMR data for these compounds are in agreement with the presence of N→Si bond. In addition to a variable temperature 1 H-NMR study was carried out showing a dynamic behavior for these compounds.

Reaction of Hydroquinones with Supported Oxidizing Reagents in Solvent-Free Conditions

Abstract Supported MnO2 or HNO3 on bentonitic clay cleanly oxidize some hydroquinones under infrared or microwave irradiation to the corresponding quinones with excellent conversion in short reaction times, using an easy and solvent-free approach.

Facile Synthesis of Aminoalcohols by Ring Opening of Epoxides Under Solvent Free Conditions

Abstract The convenient cleavage of symmetrical and unsymmetrical epoxides with either aromatic or aliphatic amine under solvent free conditions is reported. The reactions were carried out in a sealed ampoule at 90°C to give regioselectively the corresponding β‐amino alcohol in one pot in high yields.

Synthesis and X-ray characterization of new 1-[μ-dithio-bis-(tricarbonyliron)]-2-(p-R-benzoyl)ethane complexes

Diiron nonacarbonyl reacts with the para- substituted derivatives 1a – d of 3,3-dithio-1-( p -substituted phenyl)-2-propen-1-one affording surprisingly the new dinuclear Fe(0) complexes 2a – d with a σ - S coordination instead of the attended η 2 or η 4 π -coordination upon the α , β -unsaturated system of the ligands. The complexes 2a – c were characterized by mass spectrometry, IR and 1 H- and 13 C-NMR spectroscopies and their structures were fully confirmed by single-crystal X-ray analysis. Such structural studies revealed as the main feature an ideal C 2v (mm 2 ) symmetry with the carbonyl groups in an eclipsed configuration of the Se 2 Fe 2 (CO) 6 moiety.