ABSTRACT
Reduction of the quinoline ring in an alpha(v)beta(3) antagonist yielded a 1,2,3,4-tetrahydro derivative as two diastereomers, the four isomers of which were separated by sequential chiral HPLC. Two isomers had significant alpha(V)beta(3) antagonist activity with improved oral bioavailability, relative to the corresponding quinoline derivative.
Subject(s)
Integrin alphaVbeta3/antagonists & inhibitors , Integrin alphaVbeta3/metabolism , Quinolines/chemistry , Quinolines/metabolism , Administration, Oral , Animals , Biological Availability , Humans , Quinolines/administration & dosage , RatsABSTRACT
TiCl4 promoted coupling reactions of pyruvates with vinyl ethers such as 3,4-dihydro-2H-pyran or 2,3-dihydrofuran constructed quaternary carbon centers stereoselectively.
ABSTRACT
TiC14 promoted coupling of ethyl glyoxylate and dihydrofuran or dihydropyran provided oxonium ion intermediates which upon reaction with a nucleophilic trapping agent such as allyltrimethylsilane provided 2,3-disubstituted tetrahydrofurans and pyrans in good yields. The overall protocol constitutes an efficient three component coupling reaction in one pot.
ABSTRACT
The syntheses of substituted tetrahydropyrilidene acetates were accomplished by TiCl4 promoted carbon-carbon bond forming reaction of ethyl glyoxylate, 3,4-dihydro-2H-pyran and an appropriate carbon, oxygen or sulfur nucleophile. The reaction constitutes an efficient three component coupling process and the olefinic coupling product is dependent upon reaction temperature.
ABSTRACT
Suzuki coupling of stereochemically pure (Z)-bromotetraene 1-which is extremely unstable but can be kept in frozen benzene in the presence of a small amount of PPh3 at &sminus 01;20°C-and (Z)-alkenylboronic acid 2 provides the stereocontrolled synthesis of (11Z)-retinal 3. The 11Z configuration, which is introduced by selective catalytic debromination of the corresponding dibromo precursor of 1, is retained in this step. TBDMS = tBuMe2 Si.
