ChemInform Abstract: NEW TOTAL SYNTHESIS OF DL-PHYSOSTIGMINE (DL-ESERINE) VIA REGIOSELECTIVE SODIUM BOROHYDRIDE REDUCTION OF IMIDES

1978 ◽  
Vol 9 (49) ◽  
Author(s):  
J. B. P. A. WIJNBERG ◽  
W. N. SPECKAMP
Keyword(s):  
Total Synthesis ◽  
Sodium Borohydride ◽  
Borohydride Reduction ◽  
Sodium Borohydride Reduction

Nuclear analogs of β-lactam antibiotics. I. Synthesis of O-2-isocephams

1977 ◽  
Vol 55 (3) ◽  
pp. 468-483 ◽  
Author(s):  
Terrence William Doyle ◽  
Bernard Belleau ◽  
Bing-Yu Luh ◽  
Carrado F. Ferrari ◽  
Michael Patrick Cunningham
Keyword(s):  
Schiff Base ◽  
Carboxylic Acid ◽  
Total Synthesis ◽  
Sodium Borohydride ◽  
Boron Trifluoride ◽  
Cycloaddition Reaction ◽  
Phenoxyacetic Acid ◽  
Azido Group ◽  
Borohydride Reduction ◽  
Sodium Borohydride Reduction

The preparation by total synthesis of a saturated cephalosporin analog 7-β-phenoxyacet-amido-3-ethoxy-O-2-isocepham-4-α-carboxylic acid 30, is described. Compound 30 was prepared via cycloaddition of azidoacetyl chloride to the cinnamylidene Schiff base of ethyl 2-amino-3, 3-diethoxypropionate 13b to give the cis-3-azido-4-styryl β-lactam 15b. Ozonolysis of 15b followed by sodium borohydride reduction gave the alcohol 18b. Boron trifluoride treatment of 18b gave ethyl 7-β-azido-3- β-ethoxy-O-2-isocephem-4-carboxylate 27. Reduction of the azido group followed by coupling with phenoxyacetic acid and saponification of the ester gave 30. The mechanism of the cycloaddition reaction and the stereochemical assignments are also discussed.

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