Synthesis of glycos-3-yl-α,γ-diamino acids. Synthesis of four diastereomeric spiro-3,4′-(R and S)-3-deoxy-1,2:5,6-di-O-isopropylidene-α-d-ribo-hexofuranose)-3′-(R and S)-acetamido-2′-pyrrolidinones

Abstract Treatment of ( Z )-3-deoxy-1,2:5,6-di- O -isopropylidine-3- C -(methoxycarbonyl)-methylene-α- d - ribo -hexofuranose (1) with diazomethane in ether afforded the unstable Δ 1 - and Δ 2 -pyrazolines 2 and 2a . High-pressure hydrogenation of the latter compounds over Raney nickel afforded a mixture of amines 3, 5, 7 , and 9 (in 80% yield), which were separated by chromatography. Acetylation of these compounds yielded the N -acetyl derivatives 4, 6, 8 , and 10 . X-Ray analysis of compounds 8 and 10 showed them to be spiro-3,4′-( R )-(3-deoxy-1,2:5,6-di- O -isopropylidine-α- d - ribo -hexofuranose)-3′-( R )-[and 3′-( S )]-acetamido-2′-pyrrolidinone, respectively. The structures of compounds 4 and 6 (determined by chemical means) were the corresponding spiro-3,4′-( S )-3′-( R )-acetamido-2′-pyrrolidinone and 3′-( S )-acetamido-2′-pyrrolidinone, respectively.