Preparation via Diastereoselective Hydrogenation, Absolute Conformation and Configuration of Exogeneous Anabolic Zeranol ((3S, 7R)-3,4,5,6,7,8,9,10,11,12-Decahydro-7,14,16-trihydroxy-3-methy-1H-2-benzoxacyclotetradecin-1-one)
✍ Scribed by Günther Snatzke; Cristina Angeli; Enio Decorte; Flavio Moimas; Biserka Kojié-Prodié; Z̆iva Ruz̆ić-Toroš; Vitomir S̆unjić
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- German
- Weight
- 834 KB
- Volume
- 69
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Hydrogenation of the ketone group in di-0-benzylderivative (8) of the known macrocyclic lactone zeralenone (7) using a novel chiral borane complex 3.BH3, prepared in situ, proceeded at lower temperatures with moderate diastereoselectivity ( -40%, d.e. at -60"). Unsaturated diastereomers 9 and 10 were separated, and 9 converted into zeranol (It), a known anabolic agent. Restricted conformational mobility at lower temperatures is assumed for the intermediate 8 on the basis of the temperature-dependent CD spectra of its acetyl congeners 18 and 19. X-Ray structure analysis of 7-0-acetylderivative (13) of 11 revealed the (R)-configuration at C(7). Two crystallographically independent H,O molecules are involved in the H-bonds, one of them (O(21)) rises the helices of the molecules of 13 along 6. Small positive torsional angle [C(16)-]C(161)-C(I) [ = 0 1 (+19.3"), transoid(E) conformation of the lactone group, and nearly achiral arrangement of the C(ll)-C(12) bond (torsional angle [C( 1 I)-]C(12)-C(121)[C(161)] is -93") are the main conformational features that differentiate the macrocyclic RAL (resorcinic-acid lactone) derivatives from the 6-membered lactone derivative 20, studied earlier by CD. Consequently, the rules developed for the CD effects within conjugation band (around 270 nm), and n w z * band (around 255 nm) of the latter compound, cannot be applied the nmcrocyclic lactones.
Table 1. Interatomic Distances (A) ond Anales C) for Mon-H-Atoms C( 1 )-O( 1) C(1)-0(2) C(l)-C(161) c(3)-0(2) C(3)-C(31) C(3)-C(4) C(4)-C(5) C(5)-C(6) C(6)-C(7) C(7)-C(8) C(7)-O(71) C(71)-O(71) C(7 1)-O(72) C(71)-C(72) C(8)-C(9) C(9)-C( 10) C(I0)-C(l1) C(1 l)-C(12) C( 12)-C( 121) C(121)-C( 161) C(12 I )-C( 13) C( 13)-C( 14) C(14)-O( 14) C( 14)-C( 15) C( 15)-C(16) C( 16)-O( 16) C( 16)-C( 161) O( l)-C(l)-C(161) O( 1)-C( 1)-O(2) O(2)-C( 1)-C( 161) C( 1)-0(2)-C(3) 0(2)-C(3)-C(3 1) 12 1.0(2) 0(2)-C(3)-C(4) C(3 l)-C(3)-C(4) C(3)-C(4)-C(5) C(4)-C(5)-C(6) C(5)-C(6)-C(7) C(6)-C(7)-0(71) C(6)-C(7)-C(8) C(6)-C(7)-0(7 1) C(8)-C(7)-0(7 1) O(71 )-C(7 1)-O(72) 0(71)-C(71)-C(72) 0(72)-C(7 1)-C(72) C(7)-0(71)-C(71) C( 7)-C(s)-c(9) C(9)-C(10)-C(I 1) C(10)-C(11)-C(12) C( 11)-C( 12)-C(121) C(12)-C(121)-C(13) C(E)-C(9)-C( 10) C( 12)-C( 121)-C( 161) C( 13)-C( 121)-C(161) C(121)-C(l3)-C(14) C(13)-C( 14)-c(15) C( 13)-C( 14)-O( 14) O(14)-C( 14)-C( 15) C( 14)-C( 15)-C( 16) C(15)-C(16)-0(16) C( 15)-C( 16)-C( 161) 0(16)-C(16)-C(161) C( 1)-C( 161)-C( 121) C( 1)-C( 161)-C( 16) C( 16)-C(161)-C( 121 )