Molecular structure of methyl 20-isopropyl-15(E)-hydroxyimino-5,9-dimethyl-18-oxahexacyclo [12.4.0.22,13.118,20.05,10.04,13]heneicosane-9-carboxylate

Methyl 20-isopropyl-15(E)-hydroxyimino-5,9-dimethyl-18-oxahexacyclo[12.4.0.2^2,13.1^18,20.0^5,10.0^4,13]-heneicosane-9-carboxylate is synthesized and its molecular structure is determined. Compound IIa of C₂₇H₄₁NO₄ crystallizes in the acentric P2₁ space group with the following unit cell parameters: a = 7.6511(7) ?,b = 12.0698(11) ?, c = 12.9182(12) ?, β = 95.257(2)°.