... For a general review, see : B. Lythgoe, Chem. Sot. Rev., 2, 449 (1980). SJ Halkes and NP Van Vliet, Rec. Trav. Chim. Pays-Bas, s, 1080 (1969). F. Rolla and D. Landini; Chem. & Ind., 213 (1979). LJ Vanmaele, PJ De Clercq, M. Vandewalle, SJ Halkes, WRM Overbeek, Tetrahedron, 40, 1179 (1984). Absolute proof of the l(S)-configuration in la-hydroxyvitamin D3 (I&) and hence a was obtained by comparison with an authentic sample (see ref. 21.
![(4aR,6aR,7R,9aR,11S)-11-((R)-5-hydroxy-2-methyl-3-oxocyclohex-1-en-1-yl)-7-((R)-6-hydroxy-6-methylheptan-2-yl)-6a-methyl-2-phenyl-4a,6,6a,7,8,9,9a,11-octahydro-1H,5H-cyclopenta[f][1,2,4]triazolo[1,2-a]cinnoline-1,3(2H)-dione Structure](https://image.chemsrc.com/caspic/060/86307-43-9.png)
