Synthesen von 3‐Hydroxy‐4‐methyl‐3‐cyclobuten‐1,2‐dion (Methylmoniliformin)

Belluš, D.; Martin, Pierre; Sauter, Hanspeter; Winkler, Tammo

doi:10.1002/hlca.19800630504

Cited by 21 publications

(4 citation statements)

References 36 publications

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“…(b) Anisolesquarate. 3-(4-Methoxyphenyl)-4-hydroxycyclobut-3-ene-1,2-dione (anisolesquarate) was prepared according to the method of Bellus , as modified by Law and Bailey …”

Section: Methodsmentioning

confidence: 99%

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

et al. 2004

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The isomorphous polymeric complexes [M(mu-C(6)H(5)NHC(4)O(3))(2)(CH(3)OH)(2)](n) [M = Mn (1), Co (2), Cu (4), Zn (5)] are produced by reacting the anilinosquarate anion with the appropriate metal nitrates in a methanolic solution. Each of these complexes contains the central metal atom in a slightly distorted octahedral environment, with the coordination polyhedron consisting of four mu-1,2-bridging anilinosquarate ligands and two trans-oriented methanols. The polymer chains propagate to form a two-dimensional net of metal centers, with the conformation of the component sheets in the net being controlled by intramolecular N-H...O and O-H...O hydrogen bonds. Under reaction conditions similar to those used in the synthesis of the polymers 1, 2, 4, and 5, the nickel(II) monomer [Ni(C(6)H(5)NHC(4)O(3))(2)(H(2)O)(4)].2H(2)O (3) is produced in which each nickel center is attached to two cis-coordinated anilinosquarate and four aqua ligands in a distorted octahedral arrangement. The ligand conformation in 3 is stabilized by both intra- and intermolecular hydrogen bonding, which results in the formation of a sheet polymer having distinct hydrophobic and hydrophilic surfaces. Magnetochemical analysis of 1 and 4 reveals normal paramagnetic behavior for 1 and a very weak ferromagnetic interaction in 4; the absence of significant magnetic interactions is attributed to the distortion of the C(4) cycle of the anilinosquarate ligand (lower than C(2)(v) symmetry) in these complexes. Reaction of anisolesquarate with M(NO(3))(2).xH(2)O in acetonitrile produced the set of isomorphous salts [M(H(2)O)(6)][CH(3)OC(6)H(5)C(4)O(3)](2) [M = Mn (6), Co (7), Ni (8), Zn (9)]. The anisolesquarate anions in 6-9 are hydrogen bonded to the [M(H(2)O)(6)](2+) ions to form polymer chains, which are further linked by hydrogen bonds to form complex sheets. Complexation of the anisolesquarate ligand was not observed even when other solvents and reaction conditions were employed.

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“…(b) Anisolesquarate. 3-(4-Methoxyphenyl)-4-hydroxycyclobut-3-ene-1,2-dione (anisolesquarate) was prepared according to the method of Bellus , as modified by Law and Bailey …”

Section: Methodsmentioning

confidence: 99%

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

et al. 2004

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“…Anisolesquarate . 3-(4-Methoxyphenyl)-4-hydroxycyclobut-3-ene-1,2-dione (anisolesquarate) was prepared according to the method of Bellus , as modified by Law and Bailey …”

Section: Methodsmentioning

confidence: 99%

Attempted Syntheses of Lanthanide(III) Complexes of the Anisole- and Anilinosquarate Ligands

Piggot¹,

Hall²,

White³

et al. 2003

Inorg. Chem.

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The polymeric lanthanide complexes (Ln(mu-CH3OC6H5C4O3)(CH3OC6H5C4O3)2 (H2O)4.xH2O)n [Ln=La (1), Eu (2), Gd (3)], formed from the reaction of aqueous solutions of anisolesquarate and Ln(NO3)3.xH2O, are all structurally similar with only subtle differences between the lanthanum complex and the isomorphous pair of europium and gadolinium analogues. The lanthanum atom in 1 has a square antiprismatic coordination geometry comprising two pendant and two mu-1,3-bridging anisolesquarate groups and four aqua ligands. Complexes 2 and 3 have two independent metal atoms in their asymmetric units compared to one for the lanthanum complex. However, the gross structures of 1-3 are essentially the same. The asymmetric unit of the terbium complex ((CH3OC6H5C4O3)3Tb(H2O)4(mu-CH3OC6H5C4O3)(CH3OC6H5C4O3)2Tb(H2O)5).H2O (4) contains two independent binuclear units which hydrogen bond to form an extended structure very similar to those of 1-3. The ionic polymers ([Ln(mu2-C4O4)(H2O)6][C6H5NHC4O3].4H2O)n [Ln=Eu (5), Gd (6), Tb (7)] result from the incomplete hydrolysis of the anilinosquarate ion during the attempted synthesis of Eu(III), Gd(III), and Tb(III) anilinosquarate complexes. However, complete hydrolysis of the substituent is accomplished by La(III) ions, and the neutral polymer (La2(mu2-C4O4)2(mu3-C4O4)(H2O)11.2H2O)n (8) is formed. In complexes 5-7, the central lanthanide atom has a square antiprismatic geometry, being bonded to two mu-1,2-bridging squarate and six aqua ligands. Two anilinosquarate counteranions participate in second-sphere coordination via direct hydrogen bonding to aqua ligands on each metal center. These counteranions, and the included waters of crystallization, serve to link neighboring cationic polymer chains via an extensive array of O-H...O hydrogen bonds to form a 3-dimensional network. The polymeric lanthanum complex 8 contains two different metal environments, each having distorted monocapped square antiprismatic geometry. For one lanthanum atom the coordination polyhedron comprises five aqua and four squarate ligands, while for the other the polyhedron consists of six aqua and three squarate ligands; in each case one of the aqua ligands occupies the capping position. The squarate ligand exhibits two coordination modes in 8 (mu-1,2- and mu-1,3-bridging), and neighboring polymer chains are cross-linked by hydrogen bonds to form a 3-dimensional network.

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“…A solution of diethylamine hydrochloride (132 mg, 1.20 mmol) and triethylamine (0.10 mL, 1.20 mmol) in MeOH (10 mL) was added to a solution of 3-methoxy-4-methylcyclobutene-1,2-dione 33 (150 mg, 1.20 mmol) in MeOH (40 mL). After 2 h at r.t., the solution was concentrated under reduced pressure and purified by column chromatography (20-60% acetone/cyclohexane) to afford the title compound 34d 27…”

Section: -(Diethylamino)-4-methylcyclobutene-12-dione (34d) 27mentioning

confidence: 99%

Steric Buttressing Changes Torquospecificity in Thermal Cyclobutenone Rearrangements, Providing New Opportunities for 5H-Furanone Synthesis

2017

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Thermally induced rearrangements of 4-hydroxycyclobutenones are known to provide clean and reliable access to an array of useful carbocyclic and fused heterocyclic ring systems. Rarely, such reactions have been diverted to an alternative pathway leading to furanone formation. Herein, we show that these switches in the course of the rearrangement occur when a substrate bears a bulky substituent and are due to adverse steric buttressing as the transition state for electrocyclisation is approached. We also show how the reaction provides new opportunities for furanone synthesis and how bulky proton and halogen surrogates can be used to divert classical rearrangement pathways toward furanone formation. Additionally, we show that classical rearrangement pathways can be promoted by the simple expedient of alcohol protection.

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Synthesen von 3‐Hydroxy‐4‐methyl‐3‐cyclobuten‐1,2‐dion (Methylmoniliformin)

Cited by 21 publications

References 36 publications

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

Attempted Syntheses of Lanthanide(III) Complexes of the Anisole- and Anilinosquarate Ligands

Steric Buttressing Changes Torquospecificity in Thermal Cyclobutenone Rearrangements, Providing New Opportunities for 5H-Furanone Synthesis

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Synthesen von 3‐Hydroxy‐4‐methyl‐3‐cyclobuten‐1,2‐dion (Methylmoniliformin)

Cited by 21 publications

References 36 publications

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

Attempted Syntheses of Lanthanide(III) Complexes of the Anisole- and Anilinosquarate Ligands

Steric Buttressing Changes Torquospecificity in Thermal Cyclo­butenone Rearrangements, Providing New Opportunities for 5H-Furanone Synthesis

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Steric Buttressing Changes Torquospecificity in Thermal Cyclobutenone Rearrangements, Providing New Opportunities for 5H-Furanone Synthesis