Several approaches to the synthesis of penicillin from 2-iminothioazolidine
50, from 2-thiothiazolidine 66 and by photocyclization of
77 and 78 were investigated. 2-Iminothiazolidine 50 was prepared
from dibromoester 45 by the action of benzylamine followed by treatment
of aziridine 46 with potassium or ammonium thiocyanate. Attempted
introduction of a two-carbon...
Pactamycin, a potent antitumor antibiotic produced by the soil bacterium Streptomycespactum, is a structurally unique aminocyclopentitol-containing natural product. Itconsists of a highly functionalized cyclopentitol core unit, two aromatic rings [3-aminoacetophenone (3AAP) and 6-methylsalicylic acid (6MSA)], and a 1,1-dimethylurea moiety. Despite its potent biological activity, the development of thisantibiotic was hampered...
Among the myriad of naturally occurring bioactive compounds are the aminocyclopentitol-containing natural products that represent a family of sugar-derived microbial secondary metabolites, such as the antibiotics pactamycin, allosamidin, and trehazolin. Pactamycin, a structurally unique aminocyclitol antibiotic isolated from Streptomyces pactum, consists of a 5-membered ring aminocyclitol (cyclopentitol) unit, two aromatic...
The isoprenoid pathway is one of the major biosynthetic pathways of secondary metabolites. Isoprenoids with a C₂₀ skeleton are known as diterpenoids and are derived from the common precursor, geranylgeranyl diphosphate (GGPP). This dissertation describes approaches to discover the diterpene synthase enzymes which provide the backbone structures for pleuromutilin and...
The prevalence of obesity and diabetes in the United States and globally has been rising in the last few decades and it continues to climb. One of the causes for this increase is the over consumption of sugars and/or carbohydrates. Among medications available to treat obesity and diabetes are the...
The purpose of this project was to isolate gabosines and other compounds through chemical screening of secondary metabolites of Streptomyces cellulosae subsp. griseorubiginoses strain S1096. Two different media were used to cultivate S. cellulosae. The first contained soybean and mannitol. The other contained oatmeal and trace element solution. After cultivation...
This dissertation outlines the design and development of the first fully-soft, snake robot and its snake-inspired skin. Soft robotics takes advantage of soft materials to, among other things, improve robot interactions with complex, unstructured environments. Due to the interplay between the soft material and the environment, minor tweaks to the...
Gamma Ray Bursts (GRBs) are the most energetic explosions in the Universe, producing up to $\sim10^{53}$ ergs of energy in the first few seconds of their emission -- the so-called prompt phase that is dominated by high energy X-ray and $\gamma$-ray photons. The very large luminosities released in these events...
Atmospheric pressure plasma is non-thermal at millimeter to micrometer separations. It represents an alternative low exergy initiator of many chemical reactions. In many instances heat, light or sound are not efficient providers of the necessary energy to overcome chemical activation barriers. The focus of this research is applying dc nonthermal...
Among the myriad of natural products are pseudosugar-containing secondary metabolites, e.g., the C7-pseudosugar-containing oligosaccharide acarbose, the C6- pseudosugar-containing aminoglycoside antibiotics, and the five-membered ring pseudosugar-containing antibiotic pactamycin. The C7-pseudosugars are normally derived from sedoheptulose 7-phosphate catalyzed by a family of enzymes called sedoheptulose 7-phosphate cyclases (SH7PCs). This family of enzymes...