ABSTRACT
Catalytic methods allowing for the reliable prediction and control of diverse regioselectivity along with the control of enantioselectivity to access different regio- and enantiomers by switching the least reaction parameters are one of the most attractive ways in organic synthesis, which provide access to diverse enantioenriched architectures from identical starting materials. Herein, a Co-catalyzed regiodivergent and enantioselective reductive hydroalkylation of 1,3-dienes with aldehydes has been achieved, furnishing different enantioenriched homoallylic alcohol architectures in good levels of enantioselectivity. The reaction features the switch of regioselectivity tuned by the selection of proton source. The use of an acid as proton source provided asymmetric 1,2-hydroalkylation products under reductive conditions, yet asymmetric 4,3-hydroalkylation products were obtained with silane as hydride source. This catalytic protocol allows for the access of homoallylic alcohols with two continuous saturated carbon centers in good levels of regio-, diastereo-, and enantioselectivity.
ABSTRACT
Aliphatic trifluoromethyl ketones are a type of unique fluorine-containing subunit which play a significant role in altering the physical and biological properties of molecules. Catalytic methods to provide direct access to aliphatic trifluoromethyl ketones are highly desirable yet remain underdeveloped, partially owing to the high reactivity and instability of trifluoroacetyl radical. Herein, we report a photocatalytic synthesis of trifluoromethyl ketones from alkyl bromides with trifluoroacetic anhydride. The reaction features dual visible-light and halogen-atom-transfer catalysis, followed by an enabling radical-radical cross-coupling of an alkyl radical with a stabilized trifluoromethyl radical. The reaction provides straightforward access to aliphatic trifluoromethyl ketones from readily available and cost-effective alkyl halides and trifluoroacetic anhydride (TFAA).
ABSTRACT
<p><b>OBJECTIVE</b>We want to explore the harm degree of human rhinovirus in infants in Beijing area.</p><p><b>METHODS</b>From May 2008 to September 2009, 240 nasopharyngeal aspirates were collected from the children and infants who were hospitalized and with lower respiratory tract infections. These specimens were screened for HRV by real-time reverse transcription PCR (RT-PCR) and statistically analysised.</p><p><b>RESULT</b>In all of 240 hospitalized children, 208 cases were admission diagnosis of pneumonia, accounting for 86.67% (208/240), no deaths, the ratio of male and female patients was 1.93 : 1, and the collected samples reached to a maximum number in February 2009. Real-time PCR used to detect human rhinovirus, positive samples number is 71, positive rate is 29.58% (71/240), and the main symptoms and clinical diagnosis was pneumonia. Most cases were less than 2 years old, making up 81.69% (58/71), amony them, 13 months-18 months age and > or = 24 months groups have the highest incidence rates, the incidence rate is 33.33%.</p><p><b>CONCLUSION</b>Human rhinovirus happened in spring and winter seasons, especially the infants who were under 2 years are the main infection groups, the important symptoms are lower respiratory infections such as pneumonia, bronchitis and bronchiolitis et al. Human rhinovirus is seasonal and contagious, spreads fast, so protective measures in hospitals should be prepared to avoid cross-infection.</p>
Subject(s)
Child , Child, Preschool , Female , Humans , Infant , Male , China , Picornaviridae Infections , Virology , Respiratory Tract Infections , Virology , Rhinovirus , Genetics , SeasonsABSTRACT
<p><b>OBJECTIVE</b>To detect the presence of endothelial injury in patients with severe acute respiratory syndrome (SARS) via enhanced levels of tissue-type plasminogen activator (t-PA) and soluble thrombomodulin (sTM).</p><p><b>METHODS</b>Case patients were from Xuanwu Hospital (Capital University of Medical Sciences, Beijing, China), and all of them met clinical criteria for SARS. Healthy controls were some of the hospital employees. Endothelial injury bio-markers tPA and sTM were detected by commercial ELISA-methods.</p><p><b>RESULTS</b>Classic plasma markers of endothelial injury, tPA and sTM significantly elevated in SARS patients in comparison to controls [t-PA: 1.48 +/- 0.16 nmol/L versus 0.25 +/- 0.03 nmol/L (P<0.0001), and sTM: 0.26 +/- 0.06 nmol/L versus 0.14 +/- 0.02 nmol/L (P<0.05)]. The only patient who died had extremely high levels of these endothelial injury markers (t-PA: 2.77 nmol/L and sTM: 1.01 nmol/L). The likelihood ratio analysis indicated the excellent discriminating power for SARS at the optimal cut-point of 0.49 nmol/L for tPA and 0.20 nmol/L for sTM, respectively. Significant numerical correlations were found among these endothelial injury markers in SARS patients. The numerical coefficient of correlation Pearson r between t-PA and sTM was 0.5867 (P<0.05).</p><p><b>CONCLUSION</b>Increased plasma concentrations of tPA and sTM in patients with SARS suggest the possibility of endothelial injury. SARS patients might need anticoagulant therapy or fibrinolytic therapy in order to reverse intraalveolar coagulation, microthrombi formation, alveolar and interstitial fibrin deposition. It may not only provide a useful treatment and prognostic index but also allow a further understanding of the pathological condition of the disease.</p>
Subject(s)
Adult , Female , Humans , Male , Biomarkers , Blood , Case-Control Studies , China , Prognosis , Severe Acute Respiratory Syndrome , Blood , Thrombomodulin , Blood , Tissue Plasminogen Activator , BloodABSTRACT
<p><b>OBJECTIVE</b>To verify houseflies Musca spp. as the intermediate host of Thelazia callipaeda and reveal epidemiological situation of thelaziasis in Hubei province.</p><p><b>METHODS</b>Dogs eyes infected with T. callipaeda, 400 houseflies Musca and 259 fruitflies Amiota okadai in the city of Laohekou city (previously named as Guanghua county) of Hubei province had been investigated since September 2000. The newborn larvae of T. callipaeda from Laohekou suburbs were fed to houseflies Musca and A. okadai. Larvae used for the study were isolated from female T. callipaeda in laboratory and the susceptibility to houseflies Musca and A. okadai was observed.</p><p><b>RESULTS</b>Twenty-one dogs from Laohekou, the original epidemic areas of thelaziasis were examined and 7 positive dogs in 21 (33.3%) and 11 T. callipaeda (9 females and 2 males) were identified. From 1975 to 2000, no thelaziasis cases were found through retrospective surveys. These 200 houseflies Musca and 135 A. okadai were dissected for examination but showed all negative with the infection. However, newborn larvae of T. callipaeda were used to experimentally infect 112 houseflies Musca and 84 A. okadai and all infected flies were examined on the 20th day after inoculation. As a consequence, houseflies Musca failed to be infected but 9 in 84 (10.7%) A. okadai were positive. 26 infective larvae of T. callipaeda were obtained and 21 of them were inoculated into right eye of one rabbit. The female worm began to produce newborn larvae in 37 days after infection and 3 adult T. callipaeda (two females and one male) were obtained.</p><p><b>CONCLUSIONS</b>Fruitflies A. okadai from Hubei province were susceptible to T. callipaeda, which was similar to the result of experimental studies in Anhui province. This survey further confirmed that A. okadai was the intermediate host of T. callipaeda but not houseflies Musca. Infective resources (adult dogs, for instance) had been under controlled thus human thelaziasis had been eradicated in this rural area.</p>
