Search

Diarylmethanes are cardinal scaffolds by virtue of their unique structural feature including the presence of a benzylic CH2 group that can be easily functionalized to generate a variety of fascinating molecules holding immense importance in pharmaceutical, agrochemical, and material sciences. While the originally developed protocols for benzylic C−H functionalization in diarylmethanes employing base‐mediated and metal‐catalyzed strategies are still actively used, they are joined by a new array of metal‐free conditions, offering milder and benign conditions. With the recent surge of interest towards the synthesis of functionalized diarylmethanes, numerous choices are now available for a synthetic organic chemist to transform the benzylic C−H bond to C−C or C−X bond offering the synthesis of any molecule of choice. This review highlights benzylic methylene (CH2) functionalizations of diaryl/heteroarylmethanes utilizing various base‐mediated, transition‐metal‐catalyzed, and transition‐metal free approaches for the synthesis of structurally diverse important organic molecules, often with a high chemo‐, regio‐ and enantio‐selectivity. This review also attempts to provide analysis of the scope and limitations, mechanistic understanding, and sustainability of the transformations. [ABSTRACT FROM AUTHOR]

Objective Our studies aimed to measure the quality of antibody response to influenza vaccines in the elderly. The frequency of significant rise in hemagglutination inhibition (HAI) titer in the elderly is low and although annual vaccination reduces morbidity and mortality, better correlates of vaccine efficacy in the elderly are needed. Methods We measured the amount and avidity of serum antibodies against native H3N2 influenza glycoproteins or denatured virus (unfoldons) in pre- and post-vaccinated sera of 36 elderly subjects. Results Eighty percent of subjects had high pre-immunization antibody levels and only 13% showed ≥2fold increase after vaccination, but 33% showed ≥2fold increase in avidity. With increasing dosage there was a significant increase in avidity against unfoldons with 50% of subjects showing ≥2fold increase at the highest dose. Elderly subjects given subunit vaccine showed higher reactivity with unfoldons (78% of native) than younger subjects studied earlier who were given inactivated whole virus vaccine (19% of native). Conclusion The clear inverse relationship between pre-immunization antibody levels and antibody increase after vaccination implies that a major reason for the low frequency of antibody responses in elderly subjects is simply because they have high pre-immunization antibody levels. Only low reactivity was observed with earlier viruses. The increased proportion and avidity of antibodies against unfoldons is of concern, as these are not protective, and vaccine developers need to be aware of the role of age or vaccine formulation in inducing anti-unfoldon antibodies. [ABSTRACT FROM AUTHOR]