The Lindlar Catalyst Revitalized: A Highly Chemoselective Method for the Direct Conversion of Azides to N-(tert-Butoxycarbonyl)amines

Synthesis and biological evaluation of γ-aminophosphonates as potent, subtype-selective sphingosine 1-phosphate receptor agonists and antagonists

“…Compound 25 was deprotected with TMSBr to yield the ammonium bromide salt 26 . 35 S-GTP dependant receptor binding activity (Table 1) was determined in vitro for S1P, FTY720-P, and all final compounds, as previously communicated. 16 Briefly, the expression of individual human S1P receptors and individual G protein subunits was forced in HEK293T cells.…”

“…16 Briefly, the expression of individual human S1P receptors and individual G protein subunits was forced in HEK293T cells. The membrane bound G protein α subunits yielded data by binding the labeled, non-hydrolyzable [γ 35 S]-GTP when activated by an extracellular ligand. Following our discovery of the S1P 1,3 antagonist VPC23019 (B), the meta-substituted analogues were analyzed for their ability to antagonize S1P's endogenous activity in the [γ 35 S]-GTP assays.…”

Influence of Preparation Parameters on the Performance of Colloid-derived Oxidic Palladium Catalysts for Selective Hydrogenation of C–C Triple Bonds

“…Aside from the Lindlar catalyst, a multitude of different Pd based catalyst systems has since been published and investigated in detail [6][7][8][9][10][11][12][13][14][15][16][17][18], and structure sensitivity has recently been found to originate from carbon-rich metal surfaces suppressing the formation of dissolved, unselective hydrogen [19]. Beyond alkyne hydrogenation, the Lindlar catalyst can be successfully applied in selective hydrogenation of alkenes [20] and a,b-unsaturated aldehydes [21] as well as in the formation of Boc-protected amines from azides [22]. Irrespective of its advantages, the content of toxic lead, the need for the addition of an amine promoter and improvable robustness are major drawbacks of this complex catalyst system.…”

Highly efficient chemoenzymatic synthesis and facile purification of α-Gal pentasaccharyl ceramide Galα3nLc4βCer

“…After removal of all benzoyl protecting groups by the Zemplén condition, several methods were tested to reduce the azido group while keep the alkene group intact. Methods using PPh 3 , 36 PMe 3 , 37 or Lindlar catalyst 38 led to poor yields (30–50%). The combination of 1,3-propanedithiol and triethylamine 39 were found to be the most efficient for selective reduction of the azido group to produce LacβSph ( 5 ) in an excellent yield (94%).…”