George R. Negrete, Ph.D.
Office Phone: (210) 458-5448
Office: BSE 1.104J
Areas of Specialization
• Amino acid-derived lipids and liposomes
• Photo-harvesting dyes
• Green Chemistry
• Medicinal agent synthesis
Djan Baffoe, Terrell Smith, Mathew P. D. Mahindaratne, Mark Penick, Lorenzo Brancaleon, and George R. Negrete “Claisen rearrangement route to novel electron-rich perylenes” ARKIVOC 2012 (vi), 112-118.
Karin Y. Chumbimuni-Torres, Ramon E. Coronado, Adelphe M. Mfuh, Maria Fernanda Silva, George R. Negrete, Rena Bizios and Carlos D. Garcia "Adsorption of proteins to PDMS-like nanofilms and its effect on cellular adhesion" RSC Advances, 2011, 1, 706–714. (DOI: 10.1039/c1ra00198a)
Adelph M. Mfuh, Mathew P. D. Mahindaratne, Maritza V. Quintero, Frederick J. Lakner, Ande Bao, Beth A. Goins, William T. Phillips, and George R. Negrete “Novel asparagine-derived lipid stabilizes lipid bilayers to acidic conditions” Langmuir, 2011, 27, 0000 (dx.doi.org/10.1021/la105085k).
John F. Fuini III, Anand B. Surampudia, Mark A. Penick, Mathew P. D. Mahindaratne, George R. Negrete, Lorenzo Brancaleon “Photophysical Characterization of Novel 3,9-Dialkyloxy- and Diacyloxyperylenes” Dyes and Pigments, 2011, 88, 204–211. (doi:10.1016/j.dyepig.2010.06.009)
Sandip K. Kundu, Mathew P. D. Mahindaratne, Brian Quiñones, George R. Negrete and Edward R. T. Tiekink “(2S,4S)-3-Acryloyl-2-phenyl-6-oxoperhydropyrimidine-4-carboxylic acid” Acta Cryst. 2010, E66, o3 [doi:10.1107/S1600536809050892]
Terrill D. Smith, Mathew P. D. Mahindaratne, Mark A. Penick, George R. Negrete, Lee M. Daniels and Edward R. T. Tiekink “4,10-Diallyloxy-1,2,3,6b,7,8,9,12b-octahydroperylene” Acta Cryst. 2010, E66, o96 [doi:10.1107/S160053680905243X]
Mark A. Penick, Mathew P.D. Mahindaratne, Robert D. Gutierrez, Terrill D. Smith, Edward R.T. Tiekink, and George R. Negrete “Tandem Friedel-Crafts Annulation to Novel Perylene Analogs” J. Org. Chem. 2008, 73, 6378–6381.
Sandip K. Kundu, Mathew P.D. Mahindaratne, Maritza V. Quintero, Ande Bao, and George R. Negrete “One-pot Reductive Cyclization to Antitumor Quinazoline Precursors” ARKIVOC 2008 (ii), 33–42.
Research in the Negrete Laboratory
(Last Updated March 27, 2011)
Amino acid-derived lipids and liposomes
The goal of these studies is to enhance the competence of liposomes (nanocapsules) for medicinal agent delivery applications using novel fatty amino acids developed in our laboratory (see example below). Asparagine-derived Lipid Analogs (ALAs) dramatically enhance the acid stability of DSPC liposomes. Ongoing studies are examining 1) head group charge and chain length effects using modified ALAs, 2) UV/vis approaches to assaying lipid bilayer stability, 3) pH responsive liposomes for triggered release, 4) origin of novel lipid impact on bilayer stability, and 5) targeting liposomes with ALA-anchored ligands. We are collaborating with colleagues at UTSA and the UTHSCSA on in vitro and in vivo applications of acid stable liposomes.
Publication: Langmuir, 2011, 27, 4447–4455. (doi.org/10.1021/la105085k).
We are developing synthetic routes to new perylene compounds with potential applications in photocells and biophotonics. Dialkoxyperylenes (see below, X = alkoxy) promote photo-induced electron emission (see polyaromatic structure below). We are collaborating with colleagues at UTSA on photophysical, materials, and biophotonic studies of the compounds.
Publications: J. Org. Chem. 2008, 73, 6378–6381 and Dyes and Pigments, 2011, 88, 204–211.i
The goal of this project is to develop greener methods of asymmetric synthesis employing economical and safe components chirality transfer in hydroxylic environments. We reported the outlines of such a system in 2002, which is depicted in the scheme below. My group is continuing to investigate various aspects of this system: salts, solvent, metal cation M+, steering group (tert-butyl group in the scheme below), use of other amino acid and dienophile units, cyclocondensation mechanism, and applications to other asymmetric transformations.
Publications: Tetrahedron 2005, 61, 9495–9501; ARKIVOC 2005 (vi), 321–328; and Synlett 2002, 643–645.
Medicinal agent synthesis
We prepare novel synthetic targets in collaboration with colleagues at UTSA and at the UTHSCSA. Biological aspects of this project are conducted at the laboratories of collaborators.
Publications: ARKIVOC 2008 (ii), 33–42; J. Pharma. Exptl. Therap. 2004, 419–425; J. Pharma. Sci. 2003, 92, 1893–1904; J. Nucl. Med. 2003, 1992–1999; and Technetium, Rhenium and Other Metals in Chemistry and Biology Vol. 6, 2002, p 381–386.
Graduate and Undergraduate Training
Our most important products are the developing scientists we train. My lab strives to promote a supportive and collaborative environment where each student contributes experimentally and intellectually to advance our goals. Students are matched with projects according to his/her experience and interests. Dedicated undergraduate students become co-authors on manuscripts and all graduate students are expected to become co-authors publications and to present scientific data at regional and national meetings.
Please do communicate with me if you have any questions or comments.
Negrete Lab June 2014
Front row: Dr. Mark Penick and Jorge Garcia (MS student)
Next row behind: Bryan Gonzalez (Undergrad), Audrey Iñiguez-Gonzalez (Undergrad, off to Vanderbilt in the Fall), George R. Negrete, and Djan Baffoe (volunteer)
Next row behind: Magaly Salinas (PhD student), Jessica Burch (Undergrad), and Benjamin Reyes (Undergrad)
Back row: Nicolas Diaz (Undergrad) and Tom Willmott (Undergrad)
Click here for some previous incarnations of our research group
Our friend and collaborator Dr. Robert E. Lyle passed away recently. We are grateful for Bob’s friendship and support through the years.