The further development of procedures for the synthesis of the ansamycin antibiotics rifamycin S, 1, and streptovacin V, 2, will be addressed in this work. This will be performed utilizing known stereoselective procedures coupled with the Lewis acid activation of hindered epoxides, methodology that we have been developing in the laboratory. The first approach involves the sequential coupling of fragments of the type 6 and 7 which can be synthesized economically from enantiomeric but otherwise identical precursors. This, the key step, has proven to be difficult if not impossible by previous methodologies. A solution to this problem then is expected to arise from the application of this Lewis acid methodology. This represents a synthesis of the ansa chain of rifamycin S. The second approach involves a reiterative route for the synthesis of the ansa chains for both 1 and 2 based on a modification of a sequence used for the synthesis of 1, 3-polyols.18 This involves the reaction of an organometallic reagent with a cis or trans- disubstituted epoxide, depending on the desired configuration of the methyl group in 3 followed by a stereoselective epoxidation based on the carbonate extension reaction.20 The procedure can be repeated and modified as needed until the desired carbon framework is obtained. Although it is intended for the synthesis of the ansa chains of 1 and 2 in principle it can be extended to the synthesis of other members of the family. In summary we would like to develop and improve methodologies for the synthesis of this important, biologically active, test targets as a contribution to this always expanding field.
| Ramírez-Camejo, Luis A; Maldonado-Morales, Génesis; Bayman, Paul (2017) Differential Microbial Diversity in Drosophila melanogaster: Are Fruit Flies Potential Vectors of Opportunistic Pathogens? Int J Microbiol 2017:8526385 |
| Morales-Rivera, Keyla F; Piñero Cruz, Dalice M; Prieto, Jose A (2017) Crystal structure of (-)-(S)-4-[(2S,3S,4S,Z)-3-hydroxy-4-methyl-hept-5-en-2-yl]-1,3-dioxolan-2-one. Acta Crystallogr E Crystallogr Commun 73:1070-1072 |
| García-Arriaga, Marilyn; Acosta-Santiago, Maxier; Cruz, Antony et al. (2017) Probing the Limits of Supramolecular G-Quadruplexes Using Atomistic Molecular Dynamics Simulations. Inorganica Chim Acta 468:209-222 |
| Huang, Qing; Quiñones, Edwin (2016) A spectroscopic method to determine the activity of the restriction endonuclease EcoRV that involves a single reaction. Anal Biochem 497:103-5 |
| Mège, Pascal; Schizas, Nikolaos V; Reyes, Joselyd García et al. (2015) Genetic seascape of the threatened Caribbean elkhorn coral, Acropora palmata, on the Puerto Rico Shelf. Mar Ecol (Berl) 36:195-209 |
| Morales-Rivera, Amarilys; Hernández-Burgos, Mayté M; Martínez-Rivera, Arlene et al. (2014) Anxiolytic effects of oxytocin in cue-induced cocaine seeking behavior in rats. Psychopharmacology (Berl) 231:4145-55 |
| Ramírez-Camejo, Luis A; Torres-Ocampo, Ana P; Agosto-Rivera, José L et al. (2014) An opportunistic human pathogen on the fly: strains of Aspergillus flavus vary in virulence in Drosophila melanogaster. Med Mycol 52:211-9 |
| Galindo-Cardona, Alberto; Acevedo-Gonzalez, Jenny P; Rivera-Marchand, Bert et al. (2013) Genetic structure of the gentle Africanized honey bee population (gAHB) in Puerto Rico. BMC Genet 14:65 |
| Santiago-Rodriguez, Tasha M; Rivera, Jessica I; Coradin, Mariel et al. (2013) Antibiotic-resistance and virulence genes in Enterococcus isolated from tropical recreational waters. J Water Health 11:387-96 |
| Pantoja-Feliciano, Ida Gisela; Clemente, Jose C; Costello, Elizabeth K et al. (2013) Biphasic assembly of the murine intestinal microbiota during early development. ISME J 7:1112-5 |
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