?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F8761%2F&rft.title=OLIGOMERIC+ETHYLENE+GLYCOLS+AS+SORTING+TAGS+FOR+COMBINATORIAL+SYNTHESIS&rft.creator=T%C3%BCrkyilmaz%2C+Serhan&rft.description=Certain+problems+associated+with+the+nature+of+solid+phase+combinatorial+synthesis+has+prompted+the+search+for+alternative+methods.+Among+these%2C+fluorous+mixture+synthesis+(FMS)+has+emerged+as+a+powerful+method+for+solution+phase+combinatorial+synthesis.+In+FMS+each+unique+substrate+is+tagged+with+a+perfluorinated+alkane+of+unique+length.+These+tagged+substrates+are+mixed+and+taken+through+the+desired+synthetic+steps.+The+final+products+are+then+subjected+to+fluorous+chromatography.+Elution+order+is+directly+proportional+to+fluorous+tag+length.+Thus+such+fluorous+tags+could+be+regarded+as+sorting+tags.+Other+classes+of+sorting+tags+which+are+separable+under+orthogonal+conditions+to+those+of+fluorous+tags+would+significantly+increase+the+potential+of+this+approach.+In+this+study+it+has+been+demonstrated+that+oligomeric+ethylene+glycol+(OEG)+derivatives+constitute+a+new+class+of+sorting+tags.+OEG+esters+were+separable+using+normal+phase+high+performance+liquid+chromatography+(NPLC).+Separation+was+primarily+dictated+by+OEG+chain+length+with+elution+order+being+directly+proportional+to+that+length.+Within+those+separatory+regions+the+nature+of+the+parent+substrate+played+a+secondary+role%2C+further+improving+separation.+It+has+also+been+demonstrated+that+complexation+chromatography+employing+silica+gel+containing+lithium+chloride+further+enhanced+peak+resolution.+OEGylated+analogues+of+benzyl+alcohol+have+been+prepared.+Reversed+phase+high+performance+liquid+chromatography+has+been+found+to+emphasize+the+chromatographic+nature+of+the+parent+substrate+while+still+enabling+OEG+based+separation.+The+elution+order+with+respect+to+OEG+chain+length+was+found+to+be+the+opposite+of+that+in+NPLC.+Enthalpy-entropy+compensation+has+been+demonstrated+for+all+OEG+chain+lengths+indicating+the+same+retention+mechanism+for+all+of+the+esters+studied.+These+findings+suggest+that+a+two-tier+separation+approach-first+RPLC+then+NPLC-could+significantly+increase+the+number+of+OEGylated+substrates+that+can+be+subjected+to+mixture+synthesis.+OEGylated+Evans+Auxiliaries+(OEG-EAs)+have+been+prepared+and+applied+to+mixture+syn-aldol+reactions+to+demonstrate+the+synthetic+utility+of+OEG-based+sorting+tags.+OEGs+have+been+found+to+be+inert+under+the+reaction+conditions+employed+in+the+preparation+of+and+application+of+OEG-EAs.+The+aldol+products+were+obtained+with+good+yield%2C+high+purity+and+high+enantiomeric+excess.&rft.date=2007-09-27&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F8761%2F1%2FS_Turkyilmaz-ETD-08%255B1%255D%255B1%255D.13.07.pdf&rft.identifier=++T%C3%BCrkyilmaz%2C+Serhan++(2007)+OLIGOMERIC+ETHYLENE+GLYCOLS+AS+SORTING+TAGS+FOR+COMBINATORIAL+SYNTHESIS.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++