β-diketone interactions: Part 4. The structures and properties of 1,3-diphenyl-2-methylpropane-1,3-dione,C16H14O2, and 1,3-diphenyl-2-(4-methoxyphenyl)propane-1,3-dione,C22H18O3

The X-ray crystal structures of 1,3-diphenyl-2-methylpropane-1,3-dione and 1,3-diphenyl-2-(4-methoxyphenyl)propane-1,3-dione show them both to adopt cis-diketo (Z,Z) conformations with carbonyl—carbonyl dihedral angles of 89.0(3)° (2-methyl derivative), and 85.5(4)° and 77.7(4)° for the two molecules in the asymmetric unit of the 2-(4-methoxyphenyl) derivative. These are the first acyclic β-diketones with an α-hydrogen to be reported which do not have an enol configuration in the solid state.     

Preparation and Characterization of N,N′-Dialkyl-1,3-propanedialdiminium Chlorides,N,N′-Dialkyl-1,3-propanedialdimines,and Lithium N,N′-Dialkyl-1,3-propanedialdiminates

We describe convenient preparations of N,N′-dialkyl-1,3-propanedialdiminium chlorides, N,N′-dialkyl-1,3-propanedialdimines, and lithium N,N′-dialkyl-1,3-propanedialdiminates in which the alkyl groups are methyl, ethyl, isopropyl, or tert-butyl. For the dialdiminium salts, the N₂C₃ backbone is always in the trans-s-trans configuration. Three isomers are present in solution except for the tert-butyl compound, for which only two isomers are present; increasing the steric bulk of the N-alkyl substituents shifts the equilibrium away from the (Z,Z) isomer in favor of the (E,Z), and (E,E) isomers. For the neutral dialdimines, crystal structures show that the methyl and isopropyl compounds adopt the (E,Z) form, whereas the tert-butyl compound is in the (E,E) form. In aprotic solvents all four dialdimines (as well as the lithium dialdiminate salts) adopt cis-s-cis conformations in which there presumably is either an intramolecular hydrogen bond (or a lithium cation) between the two nitrogen atoms.     

IR Study of p–π Conjugation in 2-Substituted 4-Methylene-1,3-dioxolanes and 4-Methyl-1,3-dioxoles

Selected group frequencies of the IR spectra of a number of 2-substituted 4-methylene-1,3-dioxolanes (a) and their endocyclic isomers, 2-substituted 4-methyl-1,3-dioxoles (b), have been studied to establish their usefulness as a measure of the strength of p– conjugation in the O—C=C moieties of the title compounds. In the exo compounds (a), the C=C stretching frequencies C=C and the in-phase, out-of-plane bending (wagging) frequencies CH₂ w of the =CH₂ group were found to be linearly related, besides to each other, also to the electron-donating character of the substituents and the ¹³C NMR chemical shift of the C atom of the exocyclic CH₂ group. This suggests that the two IR group frequencies of the exo isomers are linearly related to the strength of p– conjugation in the O—C=C moiety. The C=C stretching absorption of the exo compounds in the 1600–1700 cm^–1 region appeared as a doublet, shown to arise from Fermi resonance of the C=C fundamental with the CH₂ w overtone. The C=C frequencies of the endo compounds support some previous findings of an unexpected strength of p– conjugation in the 2-alkoxy derivatives. Finally, DFT calculations at the B3LYP/6-31G* level of theory are shown to give accurate predictions of the effect of 2-substituents on the group frequencies.     

Synthesis, structure and conformation of 1,3-difluorotetraphenyl benzene

The compound trifluoroiodomethane can be activated to react with the electron donor,1,4-dilithiotetraphenyl butadiene,by means of electron transfer catalysis (ETC).The structure of the product,1,3-difluorotetraphenyl,benzene (1),was determined by MS,NMR,and X-ray single crystal diffraction.The conformations of compound 1 and its derivatives were analysized by molecular mechanics.     

Syntheses,Structures, and Photoluminescent Properties of Two 2D Coordination Polymers Based on 1,3-Di(2,4-dicarboxyphenyl) Benzene and 1,3-Di(4-pyridyl)propane

Two new 2D coordination polymers, [Zn(HL)(Hbpp)]n(1) and [Cd(HL)(Hbpp)(H2O)]n(2)(H4L = 1,3-di(2,4-dicarboxyphenyl) benzene, bpp = 1,3-di(4-pyridyl)propane), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, TGA and IR spectroscopy. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 13.1031(6), b = 14.7315(7), c = 15.0041(7) A, β = 91.202(1)°, V = 2895.6(2) A3, Dc = 1.532g/cm3, Mr = 667.97, F(000) = 1376.0, μ = 0.909 mm–1, Z = 4, the final R = 0.0481 and wR = 0.1304 for 7027 observed reflections with I 2σ(I). Complex 2 also belongs to the monoclinic space group P21/n, with a = 13.6326(4), b = 14.6432(4), c = 14.9395(5) A, β = 93.132(1)o, V = 2977.84(16) A3,Dc = 1.613 g/cm3, Mr = 1445.98, F(000) = 733.0, μ = 0.794 mm–1, Z = 2, the final R = 0.0283 and w R = 0.0784 for 7230 observed reflections with I 2σ(I). Both complexes 1 and 2 form 2D net structures, which are further linked to form 3D supramolecular net structures via intermolecular hydrogen bonds and aromatic π-π stacking interactions.     

1′-Azido- and 1′-amino-1,3-dioxolan-4-ones

1,3-Dioxolanone alcohols, prepared via the addition of chiral lithium enolates of 1,3-dioxolan-4-ones to aldehydes, are suitable intermediates for the synthesis of chiral trisubstituted isoserines or trisubstituted 3-hydroxy-β-lactams. In particular, the methyl ester of 2-methyl-3-(2-furyl)isoserinic acid and two 3-methyl-3-hydroxy-β-lactams bearing either a 2-furyl or a phenyl substituent at C-(4) have been prepared. The (2R,3S) stereochemistry of the isoserine, and the (3R,4S) stereochemistry of the two β-lactams is that required for the synthesis of taxoid analogues having the side-chain with the proper (2′R,3′S) configuration.     

An ylide-like phosphasilene and striking formation of a 4π-electron, resonance-stabilized 2,4-disila-1,3-diphosphacyclobutadiene

The first N-donor-stabilized phosphasilene LSi(SiMe(3))═PSiMe(3) (L = PhC(NtBu)(2)) has been synthesized in 87% yield through 1,2-silyl migration of the (Me(3)Si)(2)P-substituted, N-heterocyclic silylene [LSi-P(SiMe(3))(2)]. Remarkably, the latter reacts with dichlorotriphenylphosphorane Ph(3)PCl(2) to give the unprecedented 4π-electron Si(2)P(2)-cycloheterobutadiene [(LSi)(2)P(2)] with two-coordinate phosphorus atoms. The striking molecular structures as well as the (29)Si and (31)P NMR spectroscopic features of both products indicate the presence of zwitterionic Si═P bonds which is also in accordance with results by DFT calculations.     

Hydrochlorination of δ2-1,3-oxazolines and 1,3-oxazolidines

The compounds 2-(ethoxycarbonylmethyl)-²-l,3-oxazoline and 1-methyl-2-(methoxycarbonylmethylene)-1,3-oxazolidine are hydrochlorinated at the C=N or C= C bond, respectively, with subsequent opening of the oxazolidine ring. Depending on the reaction conditions, this occurs regioselectively to form various products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 684–686, May, 1992     

Synthesis,Dimer Crystal Structure and Herbicidal Activity of 2-（4-Ethoxybenzoyl）cyclopentane-1,3-dione

The title compound 2-(4-ethoxybenzoyl)cyclopentane-1,3-dione(C14H14O4) was synthesized, and its crystal structure was studied. It crystallized in the triclinic system, space group P1 with a = 8.980(2), b = 9.080(2), c = 15.482(3) , α = 93.49(3), β = 93.84(3), γ = 107.27(3)°, Dc = 1.365 g/cm3, Z = 4, λ = 0.71073, μ(MoKα) = 2.769 mm-1, Mr = 246.25, V = 1198.5(4)3, F(000) = 520, the final R = 0.0559 and wR = 0.1278 for 2301 observed reflections with I 2σ(I). In the crystalline state, the molecular skeleton contains one enol grouping, which is intramolecularly hydrogen bonded to a neighboring keto O atom. Preliminary bioassay result showed that this compound provided 93.8% and 87.2% control of B. campestris and A. retroflexus at post-emergence at 375 g/hm2.     

Poly(N,N′-dichloro-N-ethyl-benzene-1,3-disulfonamide, N,N,N′,N′-tetrachlorobenzene-1,3-disulfonamide, poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide, and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide catalyzed formylation of amines and alcohols using ethyl formate under microwave irradiation

A simple, rapid, and efficient procedure for formylation of primary and secondary amines and alcohols using ethyl formate catalyzed with poly(N,N′-dichloro-N-ethyl-benzene-1,3-disulfonamide (PCBS), N,N,N′,N′-tetrachlorobenzene-1,3-disulfonamide (TCBDA), poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide (PBBS) and also N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide (TBBDA) was adopted. The reactions were performed under microwave irradiation with high yields.     

Metal derivatives of 1,3-bis(2-pyridyl)-1,3-propanedione and N,N′-dimethyl-1,3-bis(2-pyridyl)-1,3-propanedione

Complexes of transition metal ions with the oxygen-nitrogen containing ligand 1,3-bis(2-pyridyl)-1,3-propanedione (bpypH) have been synthesized. These present stoichiometries which do not conform with the usual tendency manifested by β-diketones, since molecular formulas with the composition M(bpyp)X are found. A nitrogen methylated ligand N,N′-dimethyl-1,3-bis(2-pyridyl)-1,3-propanedione methyl sulphate [dimebpypH] (MeSO₄)₂ has also been synthesized and its complexes with transition metal ions studied. The stoichiometries now, resemble those of typical β-diketones, namely [dimepyp]₂MX₄ with four anions because of the dicationic nature of the original ligand. This, together with IR evidence suggests a dual type of coordination by bpip via the β-diketone and the pyridyl moieties.     

IBX promoted one-pot condensation of β-naphthol,aldehydes, and 1,3-dicarbonyl compounds

Abstract

An efficient and mild protocol has been developed for one-pot condensation of β-naphthol, aldehydes, and 1,3-dicarbolyl compounds in presence of o-iodoxybenzoic acid has been found to be an excellent catalyst for the synthesis of tetrahydrobenzo[a]xanthen-one, 1H-benzo[f]chromen-2-yl)-one via one-pot three-component condensation of β-naphthol, aldehydes, and 1,3-dicarbonyl compounds. Short reaction time, ambient conditions, simple workup, and high yield with selective manner are some of the striking features of the present protocol.     

Synthesis, Crystal Structure and Properties of [Co(1,3- bdoaH)2·4H2O] ·4H2O with Benzene-1,3-dioxyacetate Ligand

The cobalt(II) complex C20H34O20Co has been synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. The crystal belongs to triclinic, space group P with a = 5.1374(10), b = 10.519(2), c = 12.913(3) (A), α = 86.89(3), β = 79.94(3), γ = 86.74(3)o, V = 685.3(3) (A)3, Z = 1, Mr = 653.40, Dc = 1.583 g/cm3, μ = 0.717 mm-1, F(000) = 341, the final R = 0.0657 and wR = 0.1141 for 1900 observed reflections with I > 2σ(I). The cobalt ion is six-coordinated by two O atoms of different 1,3-bdoaH- ligands and four water molecules, residing in an octahedral environment. The intermolecular hydrogen bonds form a 3-D supramolecular network structure.     

Spectral and thermochemical properties of the [Na(H2O)4] [EuL4]·0.775CH2Cl2 complex,HL = 1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)-1,3-propanedione

Reaction of Eu(NO₃)₃·6H₂O with 1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)-1,3-propanedione (HL) in the presence of NaOH affords the complex compound [Na(H₂O)₄] [EuL₄]·0.775CH₂Cl₂ (I). The spectral (UV, IR, ¹H NMR spectroscopy), and thermo-luminescent (TG-DSC-MS) properties of the complex I, as well as its fragmentation at the laser desorption ionization (LDI-MS) were studied.     

Efficient and Catalytic Conversion of Epoxides into 1,3‐Dioxolanes with LiBF4

Abstract

Lithium tetrafluoroborate catalysis the efficient conversion of epoxides with acetone to the corresponding 1,3‐dioxolanes in excellent isolated yields.     

Cyclopropanation of 1, 1-Dichloro-4-methyl-1,3-pentadiene with Diazoacetate

DuetoitswideappIicationasakeyintermediateofvariouskindsofeffectivepyrethroids,thesynthesisof3(2,2-dichlorovinyl)-2,2-dimethy(III)hasattractedmuchattentionI1-3J.Severalsyntheticmethodshavebeenreportedandsomehavebeenindustrialized.However-comparedwiththegreatamountofliteratUtreusingothermethodstosynthesizelll.onlyafewworkswerereportedaboutcyclopropanationofl,l-dichloro-4-methyl-l-3-pentadiene(I)withdiazoacetate(II),andtheirchemicaIyieldswererelativel}Io.l'~leventhoughthiskindofreactiOI1wasv…     

1,3-Dipolar cycloaddition of cyclic α-methoxynitrones, derivatives of 2H-imidazole 1-oxide and 4H-imidazole 3-oxide

The reactions of cyclic aldo- and -methoxynitrones of the 2H-imidazole-1-oxide and 4H-imidazole 3-oxide series with isocyanates, phenyl isothiocyanate, N-phenylmaleimide, and dimethyl acetylenedicarboxylate were studied. The reactions give the corresponding 1,3-dipolar cycloaddition products. 2,2-Dimethyl-4-phenyl-2H-imidazole 1-oxide does not enter into a similar reaction with isocyanates or phenyl isothiocyanate.     

Synthesis, Crystal Structure and Properties of [Co(1,3- bdoaH)_2·4H_2O]·4H_2O with Benzene-1,3-dioxyacetate Ligand

1INTRODUCTIONTheorganicaromaticcarboxylatemetalcom-plexeshavearousedmuchattentionandbeenwidelyinvestigated.However,thestrategyofdesignandsynthesisofthesecomplexesismostlyfocusedonrigidligands,suchasterephthalicacidandbenzenetricarboxylicacid,etc.[1～5].Theassemblyofcom-plexesbyusingflexiblearomaticcarboxylateli-gandsisfarlessdeveloped[6,.Phenylenedioxydia-7]ceticacids(bdoaH2)withbiologicalactivitiesandwideapplicationsinagriculture[8]areafamilyofmultidentateflexibleligandswithversatilebind…     

Base-free two-step synthesis of 1,3-diketones and β-ketoesters from α-diazocarbonyl compounds, trialkylboranes, and aromatic aldehydes

We describe a convergent, base-free two-step synthesis of 1,3-diketones and β-ketoesters from α-diazocarbonyl compounds, trialkylboranes, and aromatic aldehydes in a three-component process. The synthetic potential of this protocol was underscored by the synthesis of several symmetrical 1,3,5-triaryl-4-alkyl and 1,3,4,5-tetraryl substituted pyrazoles in a three-step sequence.