N'-hydroxy-2-methoxyethanimidamide → 5-(3-Methoxymethyl-1,2,4-oxadiazol-5-yl)-1-azabicyclo-[3.1.1]heptane oxalate salt

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Reaction Steps

A stirred solution of sodium methoxide, prepared from 290 mg (0.012 mole) of sodium in methanol (20 ml), under nitrogen was treated with methyl 1-azabicyclo[3.1.1]hept-5-ylcarboxylate (D4, 300 mg, 0.0019 mole), methoxyacetamide oxime (D10, 1.0 g, 0.0097 mole) and powdered 3A molecular sieves (2.5 g). The mixture was heated under reflux for 3.5 h, then cooled in an ice bath and adjusted to pH 6 by the addition of glacial acetic acid. The mixture was concentrated in vacuo and the residue basified with concentrated potassium carbonate solution, then shaken with ethyl acetate (100 ml). The mixture was filtered and the organic layer separated, dried (Na2SO4) and concentrated in vacuo to leave a yellow oil. This material was chromatographed twice on basic alumina, each time eluting initially with ether then with 20% ethyl acetate/ether to eventually give a colourless oil (80 mg). This was converted to its oxalate salt and crystallised from acetone to give the title compound (E9 ) as a white solid (12%) m.p. 102°-104° C.

Provenance & Evidence