The synthetic process for 2,2-dimethyl-5-nitro-5-nitroso-1,3-dioxane（DMNNDO） was improved by using tri（hydroxymethyl）nitromethane and acetone as starting materials through a ＂one-pot＂ method combined with alkali...The synthetic process for 2,2-dimethyl-5-nitro-5-nitroso-1,3-dioxane（DMNNDO） was improved by using tri（hydroxymethyl）nitromethane and acetone as starting materials through a ＂one-pot＂ method combined with alkaline hydrolysis and nitrosation reactions. The yield of DMNNDO was increased from 37% to 45%. The structure of DMNNDO was characterized by IR,^1H NMR,^13 C NMR,and elemental analysis. Also the thermal decomposition of DMNNDO was studied by using DSC and TG-DTG to find that there are primarily two exothermic decomposition processes between 90 and 300 oC. The crystal structure of DMNNDO was studied by X-ray single-crystal diffraction for the first time. The molecular structure exists as a dimeric form due to the presence of nitroso group. The crystal belongs to monoclinic system,space group C2/c with a = 14.515（3）,b = 9.955（2）,c = 11.897（2） °,β = 98.500（3）°,V = 1.6998（2） nm^3,Z = 8,D_c = 1.486 g×cm^-3,μ = 0.128 mm^-1,F（000） = 800,S = 1.055,R = 0.0358 and wR = 0.0917. In particular,DMNNDO could be easily hydrolyzed in hydrous systems and the hydrolysis mechanism in CDCl_3 was revealed by means of NMR monitoring.展开更多
Applying a stimulating current to acupoints through acupuncture needles–known as electroacupuncture–has the potential to produce analgesic effects in human subjects and experimental animals. When acupuncture was app...Applying a stimulating current to acupoints through acupuncture needles–known as electroacupuncture–has the potential to produce analgesic effects in human subjects and experimental animals. When acupuncture was applied in a rat model, adenosine 5-triphosphate disodium in the extracellular space was broken down into adenosine, which in turn inhibited pain transmission by means of an adenosine A1 receptor-dependent process. Direct injection of an adenosine A1 receptor agonist enhanced the analgesic effect of acupuncture. The analgesic effect of acupuncture appears to be mediated by activation of A1 receptors located on ascending nerves. In neuropathic pain, there is upregulation of P2X purinoceptor 3 （P2X3） receptor expression in dorsal root ganglion neurons. Conversely, the onset of mechanical hyperalgesia was diminished and established hyperalgesia was significantly reversed when P2X3 receptor expression was downregulated. The pathways upon which electroacupuncture appear to act are interwoven with pain pathways, and electroacupuncture stimuli converge with impulses originating from painful areas. Electroacupuncture may act via purinergic A1 and P2X3 receptors simultaneously to induce an analgesic effect on neuropathic pain.展开更多
文摘The synthetic process for 2,2-dimethyl-5-nitro-5-nitroso-1,3-dioxane（DMNNDO） was improved by using tri（hydroxymethyl）nitromethane and acetone as starting materials through a ＂one-pot＂ method combined with alkaline hydrolysis and nitrosation reactions. The yield of DMNNDO was increased from 37% to 45%. The structure of DMNNDO was characterized by IR,^1H NMR,^13 C NMR,and elemental analysis. Also the thermal decomposition of DMNNDO was studied by using DSC and TG-DTG to find that there are primarily two exothermic decomposition processes between 90 and 300 oC. The crystal structure of DMNNDO was studied by X-ray single-crystal diffraction for the first time. The molecular structure exists as a dimeric form due to the presence of nitroso group. The crystal belongs to monoclinic system,space group C2/c with a = 14.515（3）,b = 9.955（2）,c = 11.897（2） °,β = 98.500（3）°,V = 1.6998（2） nm^3,Z = 8,D_c = 1.486 g×cm^-3,μ = 0.128 mm^-1,F（000） = 800,S = 1.055,R = 0.0358 and wR = 0.0917. In particular,DMNNDO could be easily hydrolyzed in hydrous systems and the hydrolysis mechanism in CDCl_3 was revealed by means of NMR monitoring.
文摘Applying a stimulating current to acupoints through acupuncture needles–known as electroacupuncture–has the potential to produce analgesic effects in human subjects and experimental animals. When acupuncture was applied in a rat model, adenosine 5-triphosphate disodium in the extracellular space was broken down into adenosine, which in turn inhibited pain transmission by means of an adenosine A1 receptor-dependent process. Direct injection of an adenosine A1 receptor agonist enhanced the analgesic effect of acupuncture. The analgesic effect of acupuncture appears to be mediated by activation of A1 receptors located on ascending nerves. In neuropathic pain, there is upregulation of P2X purinoceptor 3 （P2X3） receptor expression in dorsal root ganglion neurons. Conversely, the onset of mechanical hyperalgesia was diminished and established hyperalgesia was significantly reversed when P2X3 receptor expression was downregulated. The pathways upon which electroacupuncture appear to act are interwoven with pain pathways, and electroacupuncture stimuli converge with impulses originating from painful areas. Electroacupuncture may act via purinergic A1 and P2X3 receptors simultaneously to induce an analgesic effect on neuropathic pain.
