Enantiospecific Synthesis of Natural (−)-Cocaine and Unnatural (+)-Cocaine from d- and l-Glutamic Acid
摘要:
Natural (-)-cocaine and unnatural (+)-cocaine have been synthesized enantiospecifically from D- and L-glutamic acid, respectively. The axial-equatorial substitutents were introduced by a stereo- and regiospecific dipolar cycloaddition to the corresponding (LR,5S)- and (1S,5R)-N-BOC-nortropenes with (ethoxycarbonyl)formonitrile N-oxide. A sequence of subsequent stereochemically controlled transformations converted the fused isoxazoline to the requisite P-hydroxy ester. Synthesis of the key intermediate N-BOC-nortropenes involved construction of the 8-azabicyclo[3.2.1]octane framework by Dieckmann condensation of cis-5-substituted D-and L-proline esters. For comparison, (1R,SS)-N-BOC-nortropene also was derived by degradation from natural cocaine. The cis-5-substituted D-and L-proline esters were obtained by sulfide contraction and subsequent catalytic hydrogenation to induce stereospecifically the C-5 stereochemistry from D-and L-thiopyroglutamate, which in turn were prepared from D-and L-glutamic acids, respectively.
The present invention provides compounds of Formula (I):
or a stereoisomer, or a pharmaceutically acceptable salt thereof, wherein all of the variables are as defined herein. These compounds are agonists, partial agonists and modulators of the NPY Y4 receptor and may be used for the treatment and prophylaxis of various diseases and conditions.
The present invention provides compounds of Formula (I):
or a stereoisomer, or a pharmaceutically acceptable salt thereof, wherein all of the variables are as defined herein. These compounds are agonists, partial agonists and modulators of the NPY Y4 receptor and may be used for the treatment and prophylaxis of various diseases and conditions.