1-Deoxymaxacalcitol, the 1-deoxygenated derivative of maxacalcitol practically used for the treatment of secondary hyperparathyroidism and psoriasis, has been synthesized for the biological evaluation. Although purification of the key intermediate containing 1,3-cyclohexadiene moiety was extremely difficult owing to inseparable contaminants, treatment of the mixture with the heterocyclic dienophile 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) formed the readily separable Diels-Alder adduct from which the target 1-deoxymaxacalcitol could be obtained in a pure state.
1-Deoxymaxacalcitol, the 1-deoxygenated derivative of maxacalcitol practically used for the treatment of secondary hyperparathyroidism and psoriasis, has been synthesized for the biological evaluation. Although purification of the key intermediate containing 1,3-cyclohexadiene moiety was extremely difficult owing to inseparable contaminants, treatment of the mixture with the heterocyclic dienophile 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) formed the readily separable Diels-Alder adduct from which the target 1-deoxymaxacalcitol could be obtained in a pure state.