Isotope labelling in ring a of gibberellin a 20
1986; Elsevier BV; Volume: 42; Issue: 12 Linguagem: Inglês
10.1016/s0040-4020(01)87385-3
ISSN1464-5416
AutoresKumyul S. Albone, Jake MacMillan, Andrew R. Pitt, Christine L. Willis,
Tópico(s)Steroid Chemistry and Biochemistry
ResumoFull assignments of the 1H-nmr chemical shifts of the ring A protons in gibberellin A20 methyl ester 13-acetate have been made on the basis of 1H-, 2H- and 13C-nmr data of various deuteriated derivatives. These assignments have been used to prove that catalytic deuteriogenation of GA5-16, 17- epoxide-13-acetate is a syn-addition from the less hindered β-face accompanied by allylic exchange at C-1 giving isotopic labels at the 1β-, 2β- and 3β- positions. The position and stereochemistry of isotopic labelling was confirmed by comparison with an authentic sample of [1β,2β,3β-2H3] GA20 methyl ester 13-acetate prepared by methods which introduce deuterium stereoselectively at C-1, C-2 and C-3. The preparation of [2α-2H]GA20 and [3α-2H]GA20 is described.
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