Bioethanol is an appealing alternative to petroleum-based liquid fuel due to drivers such as environmental regulations and government mandates. Second generation lignocellulosic feedstocks are abundant, but their resistance to hydrolysis continues to be problematic. Different pretreatments have been proposed to increase cellulose reactivity. Softwood pine autohydrolyzed at different severities was subjected to further treatment to increase fibre reactivity. Liquid hot water is most effective at removing barriers, with the highest increase in sugar yield after enzymatic hydrolysis. Alkaline (NaOH) is found to be the worst option compared to dilute acid and organosolv. In addition, higher chemical concentrations and longer treatment times do not guarantee higher enzymatic hydrolysis yield. Process modifications such as fiber washing and multistage enzymatic hydrolysis are observed to be effective at increasing yield. However, more research is required to bring the enzymatic hydrolysis yield to a level where commercialization is feasible.

Construction of nanoassemblies from degradable components is desired for packaging and controlled release of active therapeutics, and eventual biodegradability in vivo. In this study, shell crosslinked micelles composed of biodegradable poly(lactide) (PLA) core were prepared by the self-assembly of an amphiphilic diblock copolymer synthesized by a combination of ring opening polymerization (ROP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. Enzymatic degradation of the PLA cores of the nanoparticles was achieved upon the addition of proteinase K (PK). Kinetic analyses and comparison of the properties of the nanomaterials as a function of degradation extent will be discussed. Building upon our findings from selective-excavation of the PLA core, enzyme- and redox-responsive nanoparticles were constructed for the encapsulation and stimuli-responsive release of an antitumor drug. This potent chemotherapeutic, otherwise poorly soluble in water was dispersed into aqueous solution by the supramolecular co-assembly with an amphiphilic block copolymer, and the release from within the core of these nanoparticles were gated by crosslinking the hydrophilic shell region with a reduction-responsive crosslinker. Enzyme- and reduction-triggered release behavior of the antitumor drug was demonstrated along with their remarkably high in vitro efficacy. As cationic nanoparticles are a promising class of transfection agents for nucleic acid delivery, in the next part of the study, synthetic methodologies were developed for the conversion of the negatively-charged shell of the enzymatically-degradable shell crosslinked micelles to positively-charged cationic nanoparticles for the complexation of nucleic acids. These degradable cationic nanoparticles were found to efficiently deliver and transfect plasmid DNA in vitro. The hydrolysis of the PLA core and crosslinkers of the nanocarriers may provide a mechanism for their programmed disassembly within endosomes, which would in-turn promote endosomal disruption by osmotic swelling, and release of active therapeutics from the polymeric assemblies. In the last part, a comparative degradation study was performed between the anionic and cationic micellar assemblies in the presence of two model enzymes, and electrostatic interaction-mediated preferential hydrolysis was demonstrated between the oppositely-charged enzyme-micelle pairs. These findings may be of potential significance toward the design of charge-mediated enzyme-responsive nanomaterials that are capable of undergoing environmentally-triggered therapeutic release, disassembly or morphological alterations under selective enzyme conditions.

Racemic metyhl 3-cyclohexene-1-carboxylate was resolved via enzymatic hydrolysis to afford the enantiomerically enriched 3-cyclohexene-1-carboxylic acid with PLE (S-configuration), HLE (S-configuration), CCL (S-configuration) and PPL (R-configuration) . The nucleoside&amp / #65533 / s precursor, 5-(hydroxymethyl)-2-cyclohexen-1-ol (19), was synthesized by iodolactonization, followed by iodine elimination and the reduction of the lactone. In connection with this work, alpha,beta-unsaturated and saturated cyclic ketones were selectively oxidized on alpha&#039 / - and alpha-positions using Mn(OAc)3 and Pb(OAc)4, respectively. The resultant racemic alpha&#039 / - and alpha-acetoxylated substrates were resolved into corresponding enantiomerically enriched alpha&#039 / - and alpha-hydroxylated and acetoxylated compounds via PLE hydrolysis.

Chiral cyclic alkenols with hydroxymethyl functionality are important structural units in many biologically active natural compouds such as prostaglandins, sesquiterpene antiviral agents, pentenomycins, xanthocidin, sarkomycin, etc. 1,3-cycloalkanediones are converted into bicyclic polyoxo derivatives with formaldehyde and trioxane in the presence of Lewis acid. Selective oxidation of the bicyclic compounds by using manganese(III)acetate followed by enzyme-catalyzed kinetic resolution afforded chiral bicyclic hydroxy ketones. Reduction of carbonyl group and cleavage of the ether functionality furnished the desired chiral cycloalkanols with hydroxymethyl group. This study is a model for the synthesis of these type of compounds.

&amp / #945 / ,&amp / #946 / -Unsaturated cyclic ketones were selectively oxidized on &amp / #945 / &#039 / - positions using Mn(OAc)3 and Pb(OAc)4, respectively. The resultant racemic &amp / #945 / &#039 / -acetoxylated substrates were resolved into corresponding enantiomerically enriched &amp / #945 / &#039 / -hydroxylated and &amp / #945 / &#039 / -acetoxylated compounds via PLE hydrolysis. &amp / #945 / &#039 / -Hydroxylated compounds are racemized quickly, so they were acetylated with acetyl chloride and pyridine in situ to give the corresponding &amp / #945 / &#039 / -acetoxylated compounds. Resultant &amp / #945 / &#039 / -acetoxy &amp / #945 / ,&amp / #946 / -unsaturated cyclic ketones reacted with excess amount of diazomethane under the catalsts of Pd(OAc)2 to give the resulting bicyclic diastereomeric products. At the end of the experiment, Enantiomeically enriched 2-oxobicyclo[3.1.0]hexan-3-yl acetate and 2-oxobicyclo[4.1.0]heptan-3-yl acetate were chemoenzymatically synthesized.

ABSTRACT SYNTHESIS AND ENZYMATIC RESOLUTION OF VARIOUS CYCLOPENTENOID AND CYCLOHEXENOID TYPE COMPOUNDS iyig&uuml / n, &Ccedil / igdem Ph. D., Department of Chemistry Supervisor: Prof. Dr. Cihangir Tanyeli June 2005, 174 pages The aim of this thesis is to synthesize enantiomerically enriched cyclopentenoid and cyclohexenoid type of compounds with quaternary carbon stereocenters that are the simplest precursors of the complex natural products. The first part of the study involves the preparation of &amp / #945 / &#039 / -acetoxy &amp / #945 / &#039 / -substituted &amp / #945 / ,&amp / #946 / -unsaturated cyclic ketones. Methylation, ethylation, benzylation and allylation of cyclohexenone and cyclopentenone derivatives are performed. Then, these compounds are regioselectively oxidized at the &amp / #945 / &#039 / -position by Mn(OAc)3. This is the first successful example in the literature that &amp / #945 / &#039 / -tert-position is oxidized by Mn(OAc)3. The oxidations were also performed by Pb(OAc)4 and both methods were compared. Related to this study, in the second part, the enantiomeric resolution of the acetoxy derivatives were performed by various hydrolases. This study is the first example where the hydrolases are used to resolve tertiary positions. Among the enzymes used, Candida cylindracea lipase (CCL) showed the best enantioselectivity.

Chiral hydroxylated cyclopentane derivatives are important precursors for biologically active compounds. Synthesis of these types of compounds in optically pure form found increased interest in pharmaceutical chemistry. 2-ethyl-cyclopentane-1.3-dione was acetoxylated using manganese III acetate at preferred positions. Enzyme catalyzed enantioselective hydrolysis or enantioselective acetoxylation of hydrolyzed acetoxy derivatives gives the corresponding hydroxylated diketones in optically pure form.

An applicable method for the racemic synthesis of 1,2-amino alcohols having tertiary alcohol moiety was developed. This method can be used as a general method for the synthesis of various 1,2-amino alcohols with various tertiary alcohol moieties by changing chloroacetone with different monohalo ketones, and with different aryl halides or alkyl halides. The resultant racemic 1,2-aminoe alcohols were tried to resolve by using various hydrolase type enzymes under different conditions by changing the parameters i.e. solvent, temperature and substrate: enzyme ratios. Finally, poorly resolved amino alcohol 20 with 21 % was used as chiral ligand in diethyl zinc reaction to benzaldhyde and afforded (R)-1-phenylpropan-1-ol almost with 21 % e.e..

Chiral hydroxylated cyclopentane derivatives are important structural units in many biologically active compounds and are also important synthons for the asymmetric synthesis of natural products. Synthesis of these types of compounds in optically pure form found increased interest in pharmaceutical chemistry. For this purpose 5-acetoxy-3-methyl-2-methoxy-2-cyclopentene-1-one and 5-acetoxy-3-ethyl-2-methoxy-2-cyclopentene-1-one were acetoxylated using manganese (III) acetate at a&rsquo / positions. Enzyme catalyzed enantioselective hydrolysis of hydrolyzed acetoxy derivatives gives the corresponding hydroxylated diketones in optically pure form.

Conventional free-radical miniemulsion polymerization has been well studied since early 1970s. Conventional free-radical miniemulsion polymerizations have inherent limitations associated with uncontrolled free-radical polymerization mechanism. The goal of this work is to develop a variety of unconventional miniemulsion polymerization techniques by applying new polymerization techniques (typically in solution or bulk) to miniemulsion systems to overcome their inherent limitations and extend the application of free-radical miniemulsion polymerization. This work focused on the exploration of kinetic and mechanistic aspects of unconventional miniemulsion polymerizations. First, enzyme initiated free-radical miniemulsion polymerization, in contrast with those conventional chemical initiated miniemulsion polymerization, is demonstrated for the first time as an answer to the challenges associated with using the hydrophobic of vinyl monomers in aqueous enzymatic reactions. A procedure for enzyme initiated free-radical miniemulsion polymerization was formulated and stable poly(styrene) latexes were successfully synthesized. The kinetics of enzyme initiated free-radical miniemulsion polymerization and the effect of reaction conditions on the polymerization was elucidated. Second, RAFT miniemulsion polymerization of hydrophobic monomers was performed in CSTR trains and the transient states, previously identified by others in our group, were elucidated. Next, RAFT miniemulsion polymerization of a partially water soluble monomer was studied. RAFT miniemulsion polymerizations of gamma-methyl-alpha-methylene-gamma-butyrolactone, a partially water soluble lactone monomer derived from renewable sources, was successfully formulated. Homogeneous nucleation was found to play an important role in the free-radical "miniemulsion" homopolymerization of MeMBL. By using styrene as a comonomer, the RAFT miniemulsion polymerizations of MeMBL and styrene were well controlled and narrowly distributed copolymers of MeMBL/styrene were produced. Following the study of the partially water monomer, RAFT inverse miniemulsion polymerization was proposed for the polymerization of hydrophilic monomers. The kinetics of RAFT inverse miniemulsion polymerization of acrylamide exhibited the typical behavior of controlled polymerizations up to high conversions. The effects of reaction parameters on the polymerization rate and particle size were investigated. The dominant locus of radical generation for particle nucleation and the fate of desorbed monomeric radicals in inverse miniemulsion polymerizations were evaluated. Finally in this work, conclusions and implications are presented and ideas for future work are suggested.