Synthesis and structure of 2,4,6,8-tetramethyl-3,7-dithia-2,4,6,8-tetraazabicyclo[3.3.0]octane 3,3,7,7-tetraoxide

Condensation of N,N′-dimethylsulfamide with glyoxal gave 2,4,6,8-tetramethyl-3,7-dithia-2,4,6,8-tetraazabicyclo[3.3.0]octane 3,3,7,7-tetraoxide, a sulfur-containing analog of 2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione (Mebicar). The product structure was studied by X-ray analysis.     

Reaction of 1,3,5-tri-tert-butylbenzene with 2,4,6,8-tetraiodo-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione

Reactions of 1,3,5-tri-tert-butylbenzene with 2,4,6,8-tetraiodo-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione in acetic and trifluoroacetic acids involve substitution of one or two tert-butyl groups in the aromatic ring with formation of mono-, di-, and triiodo-substituted derivatives. No iodo derivatives are formed in acetonitrile.     

New Synthesis of 2,4,6,8-Tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione Using Etidronic Acid as a “Green” Catalyst

Russian Journal of Organic Chemistry - A new method has been developed for the synthesis of 2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione in 62% yield using etidronic acid...     

2,4,6,8-Tetraiodo-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione as a mild and convenient reagent for iodination of aromatic compounds

2,4,6,8-Tetraiodo-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione (tetraiodoglycoluril) is a convenient reagent for preparative iodination of benzene, alkylbenzenes, polycyclic hydrocarbons, aromatic amines, and phenol ethers in organic solvents under mild conditions.     

N-Silylation of 2,4,6-Trialkyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones

N-Trimethylsilyl derivatives of 2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones have been prepared for the first time and the electrophilic substitution reaction of the trimethylsilyl group has been studied.     

Three-dimensional structures and spectra of 2,6- and 2,8-diethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones

Isomeric 2,6- and 2,8-diethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones were obtained by the reaction of glyoxal with ethylurea, and their crystal structures and IR, Raman, and PMR spectra were studied.Translated from Khimiya Geterotsikiicheskikh Soedinenii, No. 7, pp. 937–941, July, 1991.     

Synthesis of chiral glycolurils from (<Emphasis Type="Italic">S</Emphasis>)-(+)- and (<Emphasis Type="Italic">R</Emphasis>)-(-)-1-<Emphasis Type="Italic">sec</Emphasis>-butyl-3-methylurea

Chiral dialkyl- and tetraalkylglycolurils have been obtained using chiral (S)-(+)- and (R)-(-)-1-sec-butyl-3-methylurea as starting materials. The diastereomer (S)-(+)-2,6-di-sec-butyl-4,8-dimethyl-2,4,6,8-tetraazabicyclo[3.3.0]-octane-3,7-dione was separated into stereoisomers, for the higher melting of which the absolute configuration was determined as (S,S,S,S) by X-ray structural analysis.     

Alternative syntheses of the new D2d symmetric tetramethyl tricyclo- [3.3.0.0(3,7)]octane-1,3,5,7-tetracarboxylate

Two alternative syntheses of the new D2d symmetric tetramethyl tricyclo[3.3.0.0(3,7)]octane-1,3,5,7-tetracarboxylate from the known dimethyl 3,7-dioxo-cis-bicyclo[3.3.0]octane-1,5-dicarboxylate and 1,5-(2,2'-biphenylene)-cis-bicyclo[3.3.0]octane-3,7-dione are described.     

Temperature effect on the volume properties of a bisurea aqueous solutions

The densities of aqueous solutions of bisurea (2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione) were measured using a vibrating-tube densimeter at 288.15, 298.15, 308.15, and 318.15 K in the concentration range up to ∼3·10⁻³ moles of solute (1000 g of H₂O)⁻¹ with the error at most ±5· 10⁻⁶ g cm⁻³ (reproducibility up to 2·10⁻⁶ g cm⁻³). The limiting partial molar volume and expansibility of bisurea in water were calculated. The bicyclic molecules under study form in aqueous solution H-bonded hydrate complexes with rather high structure-packing density. These complexes are more subjected to the destroying effect of temperature than the corresponding urea complexes. The hydration of bisurea weakens with the temperature increase. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1929–1932, October, 2007.     

Reaction of Alkyl 2-Bromoalkanoates with Zinc and Arylglyoxales

Methyl 2-bromo-2-methylpropionate reacts with zinc and arylglyoxals under conditions of Reformatsky reaction in ether-HMPA mixture to afford 1-aryl-4,4,8,8-tetramethyl-2,6-dioxabicyclo[3.3.0]octane-3,7-diones in 68-85% yield. Methyl 2-bromopropionate reacts with zinc and 4-bromophenylglyoxal in the same way giving the bicyclic product in 28% yield. The bromination of 1-(4-tolyl)-4,4,8,8-tetramethyl-2,6-dioxabicyclo[3.3.0]octane-3,7-dione with bromosuccinimide results in successive replacement of hydrogens in the tolyl moiety by bromine. The calculation of formation enthalpy for stereoisomers of compounds obtained in AM1 approximation predicts the highest stability for chair-type conformation with eclipsed position of substituents at C¹ and C⁵ atoms.     

Additivity of the lanthanide induced chemical shifts in rigid compounds with two identical functional groups

The NMR spectra of anemonin, tetrahydroanemonin and cis-bicyclo[3.3.0]octane-3,7-dione, rigid compounds with two identical functional groups, in the presence of Eu(FOD)₃ are studied. The additivity of the lanthanide induced chemical shifts due to “coordination” of europium atoms at both functions is shown, while the trans configuration of the lactone rings of anemonin and the cis ring fusion in bicyclo[3.3.0]octane-3,7-dione is confirmed.     

Synthesis and separation of stereoisomeric 2,4,6,8-tetrasubstituted 3,7-dithia-1,5-diazabicyclo[3.3.0]octanes

Heterocyclization of hydrazine with aldehydes R-CHO (R = Me, Et, Prⁿ, Buⁿ, n-C₅H₁₁, Ph, 4-MeOC₆H₄, 3-Py) and H₂S leads to stereoisomeric 2,4,6,8-tetrasubstituted 3,7-dithia-1,5-diazabicyclo[3.3.0]octanes, which were separated by column chromatography. The trans-transoid-trans-configuration of tetramethyl(-ethyl,-propyl)-3,7-dithia-1,5-diazabicyclo-[3.3.0]octanes was inferred from the X-ray diffraction and ¹H and ¹³C NMR spectroscopic data.     

Reaction of dicarbonyl compounds with dimethyl 3-ketoglutarate. Influence of steric effects on success of the condensation

The influence of steric factors on the synthesis of substituted bicyclo[3.3.0]octane-3,7 diones $\text{via}$ the condensation of 1,2-dicarbonyl compounds with dimethyl 3-ketoglutarate $\text{2}$ is described.     

Chiral 6-phenyl-2,3-bismethylenemethoxycarbonyl-[1,4]-dioxane as a designer synthon for an efficient and short synthesis of optically pure 2,6-dioxabicyclo[3.3.0]octane-3,7-dione

Chiral 6-phenyl-2,3-bismethylenemethoxycarbonyl-[1,4]-dioxane, synthesized by the PET cyclization of 8, has been used as a designer synthon for an efficient and short synthesis of optically pure 2,6-dioxabicyclo[3.3.0]octane-3,7-dione.     

Reactions of diazaphospholes with phenyldiazomethane

Conclusions The action of 2-acetyl-5-methyl-1, 2, 3-diazaphosphole on phenyldiazomethane at –15°C in hexane leads to 2-acetyl-4-methyl-8-phenyl-1-phospha-2,3,7,8-tetraazabicyclo[3.3.0]octa-3,7-diene. The inverse action of phenyldiazomethane on 2-acetyl-5-methyl-1,2, 3-diazaphosphole at 0°C in ether gives 4, 11-diacetyl-6,7-dimethyl-2-phenyl-4,5,10,11-tetraaza-1,3-diphosphatricyclo[6.3.0.0^3,7]undeca-5, 9-diene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 412–418, February, 1986.     

Chemistry of bicyclic ureas. 5. Synthesis of 2,4,6,8-tetraazabicyclo[3.3.0]-3-octanone-7-thiones

Conclusions A convenient method was developed for the synthesis of 2,4,6,8-tetraazabicyclo[3.3.0]-3-octanone-7-thiones by reacting the 4,5-dihydroxy- and 4,5-dimethoxy-2-imidazolidinethiones with substituted ureas.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1594–1597, July, 1980.     

Conformational and stereoelectronic control in ring-transformations of cis-4,5-dialkoxytetrahydropurine-2,6,8-triones

Divergent acid-catalysed ring-openings of 4,5-dimethoxytetrahydropurine-2,6,8-triones 2 at position 4, yielding 1-(5-methoxyhydantoin-5-carbonyl)ureas 4 (R⁷ = Me) or 5-methoxy-5-ureido-2,4,6-pyrimidinetriones 5 (R⁷ = H), can be rationalized by assuming a preference for one of two conformational isomers of the cis-fused system, associated with the N-substitution effects. Intramolecular transamidation 5 → 4 presumably occurs via a bicyclic acid aminal type intermediate 3 , heretofore misassigned as the reaction product. A curious base-catalysed rearrangement was encountered with the 5 (R¹ = R³ = Me, R⁷ = H) cases, which afforded 5-methoxy-1,5-bis(methylaminocarbonyl)hydantoins 7 . Remarkable stability of the conformationally rigid propellane type 4,5-ethylenedioxytetrahydropurine-2,6,8-triones 9 toward acids, shows that the mode of ring-opening at position 4 is controlled by powerful Stereoelectronic factors. However, an alternative ring-opening at the 1,6-bond has occurred on heating aqueous solutions of 9a (R⁷ = H); the ensuing decarboxylative rearrangement leads to 1,3-dimethylallantoin ( 12 ) and its precursor, 1-(2-hydroxyethoxy)-2,4-dimethyl-3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]octane( 11 ).     

Reaction of dimethyl sodio-3-ketoglutarate with glyoxal and substituted glyoxals: First expeditious preparation of bicyclo[3.3.0]octane-3,7-dione; synthesis and crystal structure of 5,7-dihydroxy-4-methoxycarbonyl-3-phenyl-1-indanone

A simple and efficient two-step preparation of bicyclo[3.3.0]octane-3,7-dione starting from the sodium enolate of dimethyl 3-ketoglutarate and glyoxal is described. This is an unprecedented case in which a condensation reaction of glyoxal is more successful under vigorous conditions (refluxing methanol) than under much milder ones (buffered water at ambient temperature). The major product (after hydrolysis-decarboxylation) from the analogous sequence with phenylglyoxal is 5,7-dihydroxy-4-methoxycarbonyl-3-phenyl-1-indanone, the result of a Dieckmann reaction in addition to the Michael and aldol reactions. Only the latter two occur in aqueous buffers, where the product after hydrolysis-decarboxylation is 1-phenylbicyclo[3.3.0]octane-3,7-dione. The X-ray crystal structure of the indanone reveals a novel hydrogen bonding phenomenon.     

Crystal structure of a new binuclear complex bis(2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo(3.3.0)octane-3,7-dione-o,o′)-tetraaqua-hexakis(nitrato-o,o′)-dieuropium(III)

A centrosymmetric binuclear complex of europium(III) nitrate with bicyclic bisurea (2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo(3.3.0)octane-3,7-dione, or mebicar, Mk) [Eu(C₈H₁₄N₄O₂)(H₂O)₂(NO₃)₃]₂ (I) is synthesized and its atomic structure (CIF file CCDC No. 1451437) is determined. The crystals of I are triclinic: space group \(P\overline 1 \), a = 9.8343(4) Å, b = 10.2544(4) Å, c = 10.9411(4) Å, α = 74.366(3)°, β = 67.734(4)°, γ = 67.673(4)°, V = 934.32(7) ų, ρ(calc.) = 2.03398 g/cm³, Z = 1. The europium atom is coordinated by two oxygen atoms of two Mk molecules connected by a symmetry operation, three bidentate nitrate anions, and two water molecules. The coordination polyhedron of the europium atom is a 10-vertex polyhedron, the Eu…Eu distance is 9.7433(6) Å.     

Chemistry of 2,5-bis(trimethylsiloxy)furans. II: Reactions with carbonyl compounds and the synthesis of 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane-4,8-diones

2,5-Bis(trimethylsiloxy)furan reacted with a number of substituted benzaldehydes under activation of titanium tetrachloride to give 2,6-diaryl- 3,7-dioxabicyclo[3.3.0]octane-4,8-diones.