Synthesis of D- and L-5-Oxaproline and of a New Captopril Analogue |
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Authors: | Andrea Vasella,Robert Voeffray,Janos Pless,Ren Huguenin |
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Affiliation: | Andrea Vasella,Robert Voeffray,Janos Pless,René Huguenin |
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Abstract: | The 1,3-dipolar cycloaddition of the C-t-butyloxycarbonyl-N -mannosyl-nitrone 5 , formed in situ from the partially protected D -mannose-oxime 3 and the glyoxylate 4 , to ethylene gave preferentially the (3S)-N-glycosyl-isoxazolidine 6 which was transformed into the 3-isoxazolidine-carboxylate (L -5-oxaproline ester) 12 and into some derivatives thereof. The (S)-configuration of 12 was proved by chemical correlation with a derivative of L -asparagine. The D -5-oxaproline ester was obtained from the corresponding N-ribosyl-nitrone 24 . Two protected dipeptides containing either C-terminal- ( 28 ) or N-terminal-5-oxaproline (= Opro) ( 30 ) were synthesized. Starting from 12 , the analogue 1 of captopril® ( 2 ) was prepared and its activity as an inhibitor of the angiotensin-converting-enzyme (ACE) was examined. |
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