Optimisation, scope and limitations of the synthesis of 5-aminoindolizines from oxazolo[3,2-a]pyridinium salts

(6S,7S,8S,8aS)-6-Ethyl-7,8-dihy-droxy-1,5,6,7,8,8a-hexa-hydro-indolizin-3(2H)-one monohydrate

The absolute configuration of the title compound, C₁₀H₁₇NO₃·H₂O, was assigned from the synthesis. In the mol­ecular structure, the central six-membered ring of the indolizine moiety adopts a chair conformation, with two atoms displaced by −0.578 (2) and 0.651 (1) Å from the plane of the other four atoms [maximum deviation 0.019 (2) Å] The conformation of the fused oxopyrrolidine ring is close to that of a flat envelope, with the flap atom displaced by 0.294 (1) Å from the plane through the remaining four atoms. In the crystal, one of the hy­droxy groups is hydrogen-bonded to two water mol­ecules, while the other hy­droxy group exhibits an inter­molecular hydrogen bond to the carbonyl O atom, resulting in a chain parallel to the b axis.