Thermal Behavior of N,N＇Bis[N-（2,2,2-trinitroethyl）-N-nitro]ethylenediamine

The thermal behavior and kinetic parameters of the exothermic decomposition reaction of N‐N‐bis[N‐(2,2,2‐tri‐nitroethyl)‐N‐nitro]ethylenediamine in a temperature‐programmed mode have been investigated by means of differential scanning calorimetry (DSC). The results show that kinetic model function in differential form, apparent activation energy E_a and pre‐exponential factor A of this reaction are 3(1 ‐α)^2/3, 203.67 kJ·mol^?1 and 10^20.61s^?1, respectively. The critical temperature of thermal explosion of the compound is 182.2 °C. The values of ΔS^≠ ΔH^≠ and ΔG^≠ of this reaction are 143.3 J·mol^?1·K^?1, 199.5 kJ·mol^?1 and 135.5 kJ·mol^?1, respectively.     

One‐Pot Synthesis of Pyrimido[1,2‐a]benzimidazoles under Solvent‐Free Conditions

A series of pyrimido[1,2‐a]benzimidazoles were obtained from aldehydes, 2‐aminobenzimidazole and ethyl acetoacetate in good‐to‐excellent yields by a simple, mild, and efficient procedure utilizing N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide (TBBDA) and poly(N‐bromo‐N‐ethylbenzene‐1,3‐disulfonamide) (PBBS) as catalysts.     

Cis‐1‐phosphabicyclo[3.3.0]octan

A new approach to 1‐phosphabicyclo[3.3.0]octane compounds starts from the reaction of 4‐chloro‐hepta‐1.6‐diene with Mg in THF. No Grignard rearrangement is observed. The Grignard reagent is converted into 1‐allyl‐3‐butenylphosphonous dichloride followed by reduction with LiAlH₄. Cis‐1‐phosphabicyclo[3.3.0]octane has been prepared by radical‐initiated cyclization of 1‐allyl‐3‐butenylphosphane. The bicyclic phosphane is characterized by analytical data as well as ³¹P and ¹³C NMR measurements and the reactionswith NO, S₈, KSeCN, CH₃I, Ni(CO)₄ and HSO₃F, respectively.     

Structural and conformational analysis of 1‐oxaspiro[2.5]octane and 1‐oxa‐2‐azaspiro[2.5]octane derivatives by 1H, 13C,and 15N NMR

A structural and conformational analysis of 1‐oxaspiro[2.5]octane and 1‐oxa‐2‐azaspiro[2.5]octane derivatives was performed using ¹H, ¹³ C, and ¹⁵ N NMR spectroscopy. The relative configuration and preferred conformations were determined by analyzing the homonuclear coupling constants and chemical shifts of the protons and carbon atoms in the aliphatic rings. These parameters directly reflected the steric and electronic effects of the substituent bonded to the aliphatic six‐membered ring or to C3 or N2. The parameters also were sensitive to the anisotropic positions of these atoms in the three‐atom ring. The preferred orientation of the exocyclic substituents directed the oxidative attack. Copyright © 2012 John Wiley & Sons, Ltd.     

Solvent‐free Synthesis of 1,8‐Dioxo‐octahydroxanthenes and Tetra‐hydrobenzo[a]xanthene‐11‐ones over Poly(N,N′‐dibromo‐N‐ethylnaphtyl‐2,7‐sulfonamide)

In this work, poly(N,N ′‐dibromo‐N ‐ethylnaphtyl‐2,7‐sulfonamide) (PDNES ) as a highly efficient catalyst was applied for the synthesis of 1,8‐dioxo‐octahydroxanthenes and tetra‐hydrobenzo[a]xanthene‐11‐ones under neutral and solvent‐free conditions.     

1‐Phosphabicyclo[3.2.1]octane

1‐Phosphabicyclo[3.2.1]octanes 1‐Phosphabicyclo[3.2.1]octane has been obtained by free‐radical cyclization of (2‐vinyl‐4‐pentenyl)‐phosphane in the presence of AIBN. Another approach to 1‐phosphabicyclo[3.2.1]octanes involves free‐radical cyclization of 2‐methyl‐4‐(2‐propenyl)‐phospholane synthesized by the reaction of [2‐(2‐propenyl)‐4‐pentenyl]‐phosphane with KPH₂/[18]crown‐6 in THF. The bicyclic phosphanes are characterized by reactions with CS₂, selenium, sulfur, NO, CH₃I, and HSO₃F, respectively, structural and analytical data as well as ¹H, ¹³C, ³¹P, ⁷⁷Se NMR spectral measurements. The steric crowding of the phosphanes as complex ligands has been estimated from ³¹P–¹H coupling constants according to the Tolman model. The configuration of the methyl substituents as well as the conformation of the six‐membered ring were determined by NMR parameters (coupling constants, noe's) and proved by X‐ray crystal structure analysis.     

Three‐Step Synthesis of 3‐Aryl‐2‐sulfanylthieno[2,3‐b]‐, ‐[2,3‐c]‐, or ‐[3,2‐c]pyridines from the Corresponding Aryl(halopyridinyl)methanones

A convenient three‐step procedure for the synthesis of three types of 3‐aryl‐2‐sulfanylthienopyridines 4, 8 , and 12 has been developed. The first step of the synthesis of thieno[2,3‐b]pyridine derivatives 4 is the replacement of the halo with a (sulfanylmethyl)sulfanyl group in aryl(2‐halopyridin‐3‐yl)methanones 1 by successive treatment with Na₂S?9 H₂O and chloromethyl sulfides to give aryl{2‐[(sulfanylmethyl)sulfanyl]pyridin‐3‐yl}methanones 2 . In the second step, these were treated with LDA (LiNⁱPr₂) to give 3‐aryl‐2,3‐dihydro‐2‐sulfanylthieno[2,3‐b]pyridin‐3‐ols 3 , which were dehydrated in the last step with SOCl₂ in the presence of pyridine to give the desired products. Similarly, thieno[2,3‐c]pyridine and thieno[3,2‐c]pyridine derivatives, 8 and 12 , respectively, can be prepared from aryl(3‐chloropyridin‐4‐yl)methanones 5 and aryl(4‐chloropyridin‐3‐yl)methanones 9 , respectively.