title: 3β-Acet-oxy-lup-20(29)-en-28-yl 1H-1,2,4-tri-azole-1-carboxyl-ate.
abstract: The title triterpene, C(35)H(53)N(3)O(4), is a C-28 carbamate derivative of 3β-acet-oxy-betulin prepared in a one-step reaction from the commercially available 1,1'-carbonyl-di(1,2,4-triazole) (CDT), crystallized from acetone/n-hexane. All rings are trans fused. The carbamate and acetate substituents are in axial and equatorial positions, respectively. A quantum chemical ab initio Roothaan Hartree-Fock calculation of the equilibrium geometry of the isolated mol-ecule gives values for bond lengths and valency angles in close agreement with experimental values. The calculation also reproduces the observed mol-ecular conformation, with puckering parameters that agree well with those determined from the crystallographic study.
authors: R C
authors: RC
authors: Santos
authors: A
authors: A
authors: Matos Beja
authors: J A R
authors: JA
authors: Salvador
authors: J A
authors: JA
authors: Paixão
references: Acta Crystallogr D Biol Crystallogr. 2009 Feb;65(Pt 2):148-55
references: 19171970
references: Bioorg Med Chem. 2009 Sep 1;17(17):6241-50
references: 19674909
references: Bioorg Med Chem. 2010 Jun 15;18(12):4385-96
references: 20494586
references: Acta Crystallogr Sect E Struct Rep Online. 2010 Jun 30;66(Pt 7):o1878-9
references: 21588073
references: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references: 18156677
references: Nat Prod Rep. 2006 Jun;23(3):394-411
references: 16741586
references: Anticancer Drugs. 2009 Nov;20(10):880-92
references: 19745720