18609-16-0Relevant articles and documents
Structural flexibility in the biocatalyst-mediated functionalization of ring 'A' in salannin, a tetranortriterpene from Azadirachta indica
Madyastha, K. Madhava,Venkatakrishnan, Krishnamachari
, p. 3055 - 3062 (2000)
Nocardia sp. quantitatively converts salannin 1 and 3-de-O-acetylsalannin 2 (C-seco limonoids) into 3-deacetoxy1-de[(E)-2-methylbut-2-enoyloxy]salannin-1-en-3-one 10, a novel and potentially bioactive compound with an α,β-unsaturated ketone moiety in ring 'A'. In order to establish the sequence of events involved in this transformation and the structural specificity of this bacterial system, several new derivatives of salannin 1 have been prepared. These studies have indicated that the transformation is initiated by deacetylation at C-3, followed by oxidation of the secondary hydroxy group to 3-keto, which appears to facilitate the elimination of the tigloyloxy/acetoxy group at C-l with the formation of an olefinic linkage between C-l and C-2. The organism very efficiently transforms some of the derivatives of salannin into their corresponding compounds possessing an enone system in ring 'A', an essential pre-requisite for various biological activities. Some of the C-seco limonoids prepared in the present study, viz. 10, 1,2-didehydro-1,3-dideoxy-3-oxosalannic acid 18, 3-deacetoxy-1-de[(E)-2-methylbut-2-enoyloxy]-20,21,22,23-tetrahydrosalannin-1- en-3-one 15 and 1,2-didehydro-1,3-dideoxy-3-oxosalannol 23 were hitherto not known. The Royal Society of Chemistry 2000.
Ethylenediamine: An effective reagent for deacetylation of natural products
Mohankumar, Ramasamy,Ilango, Kaliappan,Santhanakrishnan, Vichangal Pridiuldi,Radhakrishnan, Viswanathan,Narasimhan, Srinivasan
experimental part, p. 851 - 858 (2010/12/25)
The use of ethylenediamine in methanol is described for the selective cleavage of the acetate group in nimbin (1) to 6-deacetyl nimbin (1a) under microwave irradiation. This method enables to deacetylate without affecting other functional groups such as ,α,β-unsaturated ketone, ester, ether, etc. in certain tetranortriterpenoids and other acetate-containing natural compounds.
