Asymmetric Remote Aldol Cyclization Reaction to Synthesize Trifluoromethylated Heterospirocyclic Frameworks.

The highly enantioselective organocatalytic synthesis of dihydropyran spirocyclic compounds bearing di- and trifluoromethyl groups by aldol cyclization reaction via trienamine using cyclic 2,5-dienones and different di- and trifluoromethylketones is described. Using a bifunctional aminothiourea catalyst, trifluoromethyl-functionalized dihydropyran spirocyclic products were obtained with good yields and enantioselectivities. Subsequent transformation with H and Pd/C has allowed the synthesis of the tetrahydropyran structure with three stereocenters.

Tropical grass and legume pastures may alter lamb meat physical and chemical characteristics.

The present study assessed the influence of the type of the tropical pastures on lamb body weight (BW) gain and meat quality. Fifty-four lambs were allocated to three grazing pastures: (1) AG - Aruana grass (Panicum maximum cv. IZ-5); (2) PP - pigeon pea legume (Cajanus cajan cv.

Controlled human malaria infection by intramuscular and direct venous inoculation of cryopreserved Plasmodium falciparum sporozoites in malaria-naïve volunteers: effect of injection volume and dose on infectivity rates.

Background: Controlled human malaria infection (CHMI) by mosquito bite is a powerful tool for evaluation of vaccines and drugs against Plasmodium falciparum malaria. However, only a small number of research centres have the facilities required to perform such studies. CHMI by needle and syringe could help to accelerate the development of anti-malaria interventions by enabling centres worldwide to employ CHMI.