title: Structures of 3 beta-tetrahydropyranyloxy-5 alpha-cholesta-20(21),24-diene and 3 beta-tetrahydropyranyloxy-21-nor-5 alpha-ergost-24-en-20-one.
abstract: 3 beta-Tetrahydropyranyloxy-5 alpha-cholesta-20(21),24-diene: C32H52O2, Mr = 468.77, orthorhombic, P2(1)2(1)2(1), a = 6.710 (4), b = 11.361 (4), c = 37.812 (11) A, V = 2882 (2) A3, Z = 4, Dx = 1.08 g cm-3, lambda(Cu K alpha) = 1.54178 A, mu = 4.60 cm-1, F(000) = 1040, T = 224 K, final R = 0.088 for 1729 unique observed reflections. 3 beta-Tetrahydropyranyloxy-21-nor-5 alpha-ergost- 24-en-20-one: C32H52O3, Mr = 484.77, triclinic, P1, a = 6.640 (2), b = 9.589 (2), c = 12.202 (3) A, alpha = 111.33 (2), beta = 101.22, gamma = 90.27 (2) degrees, V = 707.4 (3) A3, Z = 1, Dx = 1.14 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 0.8 cm-1, F(000) = 268, T = 225 K, final R = 0.058 for 2208 unique observed reflections. The configuration at C(17) of these synthetic sterol derivatives, which had been uncertain, is unambiguously established to be 'normal' (possessing a 17 alpha-H).
authors.affiliation: Department of Chemistry, Princeton University, New Jersey 08544.
authors.forename: D
authors.initials: D
authors.lastname: Van Engen
authors.forename: M D
authors.initials: MD
authors.lastname: Rahman
authors.forename: A
authors.initials: A
authors.lastname: Yun
authors.forename: R A
authors.initials: RA
authors.lastname: Pascal
mesh_terms: D002774:Cholestadienes / Q000737:chemistry*; D004875:Ergosterol / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D014961:X-Ray Diffraction
chemical_list: D002774:Cholestadienes; C074398:3-tetrahydropyranyloxycholesta-20(21),24-diene; C074399:tetrahydropyranyloxy-21-norergost-24-en-20-one; D004875:Ergosterol