RESUMO
A flexible stereoselective approach to the common C1-C14 skeleton present in natural products of the pseudomonic acid family is described. The strategy has been extended and the total synthesis of pseudomonic acid methyl monate C was achieved. The key synthetic reactions utilized include Achmatowicz rearrangement, Johnson-Claisen rearrangement, Julia-Kocienski olefination, and Horner-Wadsworth-Emmons olefination reaction.
Assuntos
Química Orgânica/métodos , Crotonatos/síntese química , Mupirocina/análogos & derivados , Mupirocina/síntese química , Piranos/síntese química , Crotonatos/química , Indicadores e Reagentes , Mupirocina/química , Piranos/químicaRESUMO
The stereoselective protective group-free synthesis of the C1-C16 fragment of (+)-sorangicin A consisting of a dihydropyran subunit with a chiral alkyl substituent is achieved. The synthesis of the 4-stereogenic centered subunit involved key reactions such as Noyori asymmetric transfer hydrogenation, Achmatowicz oxidative rearrangement, and highly diastereoselective allylation of the Achmatowicz adduct.
Assuntos
Aminoglicosídeos/química , Aminoglicosídeos/síntese química , Técnicas de Química Sintética , Estereoisomerismo , Especificidade por SubstratoRESUMO
In the present study, the aphrodisiac activity of Butea frondonsa Koen. ex Roxb (Papillionaceae) bark extract was investigated. The extract (400 mg/kg body wt./day) was administered orally by gavage for 28 days. Mount latency (ML), intromission latency (IL), ejaculation latency (EL), mounting frequency (MF), intromission frequency (IF), ejaculation frequency (EF) and post-ejaculatory interval (PEI) were the parameters observed before and during the sexual behavior study at day 0, 7, 10, 14, 21, and 28. The extract reduced significantly ML, IL, EL and PEI (p < 0.05). The extract also increased significantly MF, IF and EF (p < 0.05). These effects were observed in sexually active and inactive male rats.