Gas-phase structure and conformational properties of 3,3,6,6-tetramethyl-1,2,4,5-tetroxane

The geometric structure and conformational properties of 3,3,6,6-tetramethyl-1,2,4,5-tetroxane (diacetone diperoxide) have been studied by gas electron diffraction and quantum chemical calculations (MP2 and B3LYP methods with 6-31G(d,p) and 6-311+G(2df,p) basis sets). The molecule possesses a chair conformation with C2h symmetry and the following geometric parameters for the six-membered ring (rh1 values) have been determined: O-O = 1.463(5) A, C-O = 1.432 (4) A, O-C-O = 108.2(7) degrees, C-O-O = 107.7(4) degrees, phi(C-O-O-C) = 63.7(4) degrees, and phi(O-O-C-O) = -63.9(4) degrees. A small contribution of less than 3.5% of a twist conformer with C2 symmetry cannot be excluded. Quantum chemical calculations predict a contribution between 1 and 2%. Additional calculations for the parent compound 1,2,4,5-tetroxane (diformaldehyde diperoxide) demonstrate that methyl substitution at the carbon atoms has a minor effect on the ring geometry but a strong effect on the conformational properties. Methyl substitution reduces the energy difference between twist and chair conformers by more than 5 kcal/mol.     

Polynuclear heterocyclic compounds. XIX. Reduction of 3,3,6,6-tetramethyloctahydroacridine-1,8-diones

Reduction in alcohol solution, using hydrogen at atmospheric pressure and platinum oxide catalyst, of 3, 3, -6, 6-tetramethyl-1, 2, 3, 4, 5, 6, 7, 8-octahydroacridine-1, 8-dione and its 9-phenyl derivative gives the corresponding 3, 3, 6, 6-tetramethyl-1, 2, 3, 4, 5, 6, 7, 8, 9, 10-decahydroacridine-1, 8-dione and its 9-phenyl derivative.For part XVIII see [1].     

Reaction of 3,3,6,6-Tetramethyl-1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-diones with Lithium Aluminum Hydride

The corresponding 3,3,6,6-tetramethyl-1,2,3,4,5,6,7,8-octahydroacridines have been obtained by the interaction of 3,3,6,6-tetramethyl-1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-dione, its 9-Ph- and 9-p-MeOC₆H₄-substituted derivatives with lithium aluminum hydride. The reaction proceeds in boiling diglyme and also at room temperature on extended stirring of the reactants in ether.     

Synthesis and Crystal Structure of 3,3,6,6-Tetramethyl-N-hydroxy-9-ethyl-1,8-dioxo-1,2,3,4,5,6,7,8,9,10-decahydroacridine

1 INTRODUCTION 1,4-Dihydropyridines (1,4-DHPs) are well-knowncompounds because of their pharmacological pro-perty as calcium channel modulators[1, . The che- 2]mical modifications, such as the introduction of dif-ferent substituents[3, or heteroatoms[5], of the DHP 4]ring have allowed the expansion of researches onthe structure-activity relationship to gain new in-sights into the molecular interactions at the receptorlevel. In fact, it is well established th…     

水中3,3,6,6-四甲基-9-芳基-1, 8-二氧代-1,2,3,4,5,6,7,8-八氢化氧杂蒽的合成

以氨基磺酸和十二烷醇硫酸钠(SDS)为复合催化剂, 芳醛和5,5-二甲基-1,3-环己二酮为原料, 于水中合成了3,3,6,6- 四甲基-9-芳基-1,8-二氧代-1,2,3,4,5,6,7,8-八氢化氧杂蒽. 方法具有操作简便, 催化剂价廉易得、活性高、对环境友好、可回收重复使用等优点.     

Thermal decomposition reaction of 3,3,6,6-tetramethyl- 1,2,4,5-tetroxane in 2-methoxy- ethanol solution

The thermal decomposition study of 3,3,6,6-tetramethyl-1,2,4,5-tetroxane (acetone cyclic diperoxide) was carried out in 2-methoxyethanol solution in the 130-166 °C temperature range. The overall reaction follows a first-order kinetic law up to at least 75% diperoxide conversion. The activation parameters (ΔH^# = 22.5 ± 0.7 kcal⋅mol^–1 and ΔS^# = -25.6 ± 0.5 cal⋅mol^–1⋅K^–1) for the unimolecular rupture of the O–O bond in the diperoxide molecule were obtained by measuring the remnant diperoxide at different reaction times by the CG technique. Acetone was detected by GC as the major organic product of the reaction.     

Transformation of 9-Aryl-3,3,6,6-tetramethyl-1,2,3,4,5,6,7,8,9,10- decahydroacridine-1,8-diones in Mineral Acids

Russian Journal of Organic Chemistry -     

可膨胀石墨催化合成3,3,6,6-四甲基-9-芳基-1,2,3,4,5,6,7,8-八氢化氧杂蒽-1,8-二酮

在可膨胀石墨催化下, 由芳香醛和5,5-二甲基-1,3-环己二酮缩合制备了3,3,6,6-四甲基-9-芳基-1,2,3,4,5,6,7,8-八氢化氧杂蒽-1,8-二酮. 在乙醇-水介质中回流反应2.5 h, 反应产率可达87%～93%. 该方法不仅反应时间短, 产率高, 而且催化剂价廉易得、对环境友好, 催化剂经简单过滤后可重复使用.     

Catalytic effect of cuprous ions on the thermal decomposition of 3,3,6,6-tetramethyl-1,2,4,5-tetraoxane in methanol solution

Thermal decomposition of 3,3,6,6-tetramethyl-1,2,4,5-tetraoxane was examined in methanol solution (1.69×10⁻² M) containing cuprous ions (5.05×10⁻⁷ M) in the temperature range from 130 to 166°C using UV spectroscopy as analytical method. The ion-catalyzed reaction follows first-order kinetics with respect to the peroxide and added cuprous ions. The temperature effect on the rate of thermal decomposition of the title compound was described by the corresponding Arrhenius equations, and its stability in solution was estimated on a quantitative level. The activation parameters of the initial step of decomposition of 3,3,6,6-tetramethyl-1,2,4,5-tetraoxane were determined (ΔH ^≠ = 14.7±0.8 kcal mol⁻¹; ΔS ^≠ = −38.9±1.4 cal mol⁻¹ K⁻¹; ΔG ^≠ = 31.0±0.8 kcal mol⁻¹). Electron-transfer mechanism was proposed for the reaction under study. The text was submitted by the authors in English.