Chromium-Mediated Stannylcyclopropanation of Alkenes with (Diiodomethyl)stannanes

A stannyl-group-substituted gem-dichromiomethane species, generated in situ from CrCl2, TMEDA, and tributyl(diiodomethyl)stannane, worked as an efficient stannylcarbene equivalent to promote cyclopropanation of alkenes. The reaction provided synthetically useful stannylcyclopropanes directly from commercially available unactivated alkenes without using potentially flammable alkylzinc and diazo compounds. Structural characterization of stannyl- and germyl-group-substituted gem-dichromiomethane complexes and the effect of group 14 elements containing substituents for cyclopropanation are also described

Synthesis of Borylcyclopropanes by Chromium-Promoted Cyclopropanation of Unactivated Alkenes

The combination of diiodomethylboronate ester, CrCl₂ with TMEDA promoted borylcyclopropanation of unactivated alkenes under mild conditions. Compared with the typical Simmons–Smith cyclopropanation, the current protocol offers the following advantages: (1) the reaction proceeds stereoselectively with disubstituted alkenes even without hydroxy or alkoxy groups; (2) both electron-rich and electron-deficient alkenes can be applicable; and (3) the reaction does not require potentially flammable alkylzinc. These unique reactivity features result from the steric and electronic nature of the <i>gem</i>-dichromiomethane intermediates

Synthesis of Borylcyclopropanes by Chromium-Promoted Cyclopropanation of Unactivated Alkenes

The combination of diiodomethylboronate ester, CrCl₂ with TMEDA promoted borylcyclopropanation of unactivated alkenes under mild conditions. Compared with the typical Simmons–Smith cyclopropanation, the current protocol offers the following advantages: (1) the reaction proceeds stereoselectively with disubstituted alkenes even without hydroxy or alkoxy groups; (2) both electron-rich and electron-deficient alkenes can be applicable; and (3) the reaction does not require potentially flammable alkylzinc. These unique reactivity features result from the steric and electronic nature of the <i>gem</i>-dichromiomethane intermediates

Cedar Pollinosis and Mortality: A Population-Based Prospective Cohort Study in Japan

Background: Cedar pollinosis is one of the most prevalent forms of seasonal allergic reaction in Japan. Only one prospective study has examined the association between cedar pollinosis and mortality. Using a symptom-based questionnaire on cedar pollinosis, we investigated the association of cedar pollinosis with all-cause and cause-specific mortality. Methods: Data came from the Takayama Study, which recruited residents aged ≥35 years in 1992 from Takayama city in Gifu Prefecture, Japan. The current study used information on cedar pollinosis that was obtained from the second survey in 2002. A total of 12,471 persons who were 45–80 years old and had no history of cancer, coronary heart disease, or stroke responded to a questionnaire asking about four symptoms related to cedar pollinosis. Mortality and migration data were obtained throughout the follow-up period up to March 2013. Cox proportional hazard models were used to examine the relation between cedar pollinosis and mortality. Results: A total of 1,276 persons died during follow-up period. Among these, there were 504 neoplasm, 278 cardiovascular, and 181 respiratory deaths. After adjusting for potential confounders, cedar pollinosis was associated with significantly lower all-cause mortality (hazard ratio [HR] 0.79; 95% confidence interval [CI], 0.65–0.95) and respiratory mortality (HR 0.38; 95% CI, 0.18–0.82). There was no significant association between cedar pollinosis and mortality due to neoplasm or cardiovascular disease. Conclusions: We found an inverse association between cedar pollinosis and the risk of all-cause and respiratory mortality. Further research is needed to elucidate the association between cedar pollinosis and mortality

Associations between Exposure to Tobacco Smoke and Behavioral Problems in Preschool Japanese Children

Background. A few studies related to pediatric behavior have measured secondhand smoke exposure in children using valid objective biochemical markers. We aimed at investigating the associations between current and cumulative exposure to tobacco smoke, measured both subjectively and objectively, and behavioral problems in children. Methods. Subjects were 437 Japanese children, aged 3–6 years in 2006. Exposure to tobacco smoke was evaluated from a parent-administered questionnaire and urinary cotinine concentrations. The cotinine concentrations were measured using first-void morning urine by liquid chromatography-tandem mass spectrometry. Children’s behaviors were assessed by the parent-completed Strengths and Difficulties Questionnaire. Results. After multiple adjustments for covariates, higher total difficulty scores of children were significantly associated with the larger number of cigarettes parents smoke, more smokers among cohabiters, and more pack-years of exposure to tobacco smoke from parents and cohabiters. The total difficulty scores were 8.72, 9.09, and 10.52, respectively, for children in the low, middle, and high tertiles of creatinine-corrected cotinine concentrations in urine (p=0.002, trend p=0.005). There was no substantial sex difference in the positive associations between passive smoking and the SDQ scores. Conclusions. Exposure to tobacco smoke in early childhood may be involved in the development of pediatric behavioral problems. The importance of reducing the exposure of children to tobacco smoke, particularly in the home, was further emphasized for the prevention of psychological and behavioral problems in childhood

Association between exposure to household smoking and dental caries in preschool children: a cross-sectional study

Abstract Background We aimed to examine the association of exposure to environmental tobacco smoke with dental caries among preschool children. Exposure to environmental tobacco smoke was assessed in terms of urinary cotinine concentrations and pack-years of exposure to smoking by parents and other family members at home. Methods This cross-sectional study included 405 preschool children aged 3–6 years from two preschools in Japan in 2006. Information on the smoking habits of family members living with the child was obtained from parent-administered questionnaires. Dental examination was conducted to assess dental caries, that is, decayed and/or filled teeth. Urinary cotinine levels were measured using first-void morning urine samples. Results Overall, 31.1% of the children had dental caries, and 29.5% had decayed teeth. Exposure to current maternal and paternal smoking was positively associated with the presence of dental caries after controlling for covariates. More than three pack-years of exposure to maternal smoking and more than five pack-years of exposure to smoking by all family members were significantly associated with the presence of dental caries as compared with no exposure (odds ratio [OR] = 5.55, 95% confidence interval [CI] = 2.17–14.22, P for trend < 0.001 and OR = 2.00, 95% CI = 1.12–3.58, P for trend = 0.004, respectively). These exposure variables were similarly associated with the presence of decayed teeth (OR = 2.92, 95% CI = 1.23–6.96, P for trend = 0.01 and OR = 1.75, 95% CI = 0.96–3.20, P for trend = 0.03, respectively). As compared with lowest tertile of the urinary cotinine level, the highest tertile of the urinary cotinine level was significantly associated with the presence of dental caries as well as decayed teeth; the ORs for the highest vs. lowest tertile of urinary cotinine levels were 3.10 (95% CI = 1.71–5.63, P for trend = 0.012) and 2.02 (95% CI = 1.10–3.70, P for trend = 0.10), respectively. Conclusions These data suggest that exposure to tobacco smoke may have a dose-dependent influence on the development of caries