graphicThe synthesis of ethyl cis-(1S,2R/1R,2S)-2-aminocyclohex-1-yl-N-(thymin-1-yl-acetyl) glycinate (10a and 10b) via enzymatic resolution of the key racemic intermediate trans-2-azido cyclohexanols 3 is reported. The crystal structures of 10 show equatorial disposition of the tertiary amide group, with the torsion angle beta in the range 60-70degrees. The PNA oligomers incorporating these show differential effects in hybridizing with complementary DNA and RNA.
graphicThe synthesis of ethyl cis-(1S,2R/1R,2S)-2-aminocyclohex-1-yl-N-(thymin-1-yl-acetyl) glycinate (10a and 10b) via enzymatic resolution of the key racemic intermediate trans-2-azido cyclohexanols 3 is reported. The crystal structures of 10 show equatorial disposition of the tertiary amide group, with the torsion angle beta in the range 60-70degrees. The PNA oligomers incorporating these show differential effects in hybridizing with complementary DNA and RNA.
Synthesis and Evaluation of (1<i>S</i>,2<i>R</i>/1<i>R</i>,2<i>S</i>)-Aminocyclohexylglycyl PNAs as Conformationally Preorganized PNA Analogues for DNA/RNA Recognition
作者:T. Govindaraju、Vaijayanti A. Kumar、Krishna N. Ganesh
DOI:10.1021/jo035747x
日期:2004.3.1
Conformationally constrained cis-aminocyclohexylglycyl PNAs have been designed on the basis of stereospecific imposition of 1,2-cis-cyclohexyl moieties on the aminoethyl segment of aminoethylglycyl PNA (aegPNA). The introduction of the cis-cyclohexyl ring may allow the restriction of the torsion angle beta in the ethylenediamine segment to 60-70degrees that is prevalent in PNA(2):DNA and PNA:RNA complexes. The synthesis of the optically pure monomers (10a and 10b) is achieved by stereoselective enzymatic hydrolysis of an intermediate ester 2. The chiral PNA oligomers were synthesized with (1S,2R/1R,2S)-aminocyclohexylglycyI thymine monomers in the center and N-terminus of aegPNA. Differential gel shift retardation with one or more units of modified monomer units was observed as a result of hybridization of PNA sequences with complementary DNA sequences. Hybridization studies with complementary DNA and RNA sequences using UV-T-m measurements indicate that PNA with (1S,2R)-cyclohexyl stereochemistry enhances selective binding with RNA over DNA as compared to control aegPNA and PNA with the other (1R,2S) isomer.
作者:T. Govindaraju、Rajesh G. Gonnade、Mohan M. Bhadbhade、Vaijayanti A. Kumar、Krishna N. Ganesh
DOI:10.1021/ol034933m
日期:2003.8.1
graphicThe synthesis of ethyl cis-(1S,2R/1R,2S)-2-aminocyclohex-1-yl-N-(thymin-1-yl-acetyl) glycinate (10a and 10b) via enzymatic resolution of the key racemic intermediate trans-2-azido cyclohexanols 3 is reported. The crystal structures of 10 show equatorial disposition of the tertiary amide group, with the torsion angle beta in the range 60-70degrees. The PNA oligomers incorporating these show differential effects in hybridizing with complementary DNA and RNA.