el-Masdouri L, Aubry A, Grand V, Marraud M
Laboratoire de minéralogie et cristallographie, UA CNRS 809, Université de Nancy I, France.
Acta Crystallogr C. 1992 Jan 15;48 ( Pt 1):173-5. doi: 10.1107/s0108270191008107.
N-(tert-Butylcarbonylglycylaminoethyl)-N-(ethyl)ammonium tetraphenylborate, C11H24N3O+2.C24H20B-, Mr = 549.57, triclinic, P-1, a = 11.567 (2), b = 11.922 (2), c = 14.484 (3) A, alpha = 70.99 (2), beta = 74.83 (2), gamma = 59.33 (1) degrees, V = 1613.1 A3, Z = 2, D chi = 1.13 g cm-3, lambda(Cu K alpha) = 1.5418 A, mu = 4.69 cm-1, mu Rmax much less than 1, F(000) = 592, T = 293 K, R = 0.058 for 3491 observed reflections. This pseudopeptide is folded by a short N(+)-H ... O = C hydrogen bond (N3 ... O1 = 2.81 A) which closes a ten-membered ring. This results in a beta-turn structure that can be classified as type II on the basis of the conformational angles for the N-terminal glycine. The conformational angles phi 1, psi 1, phi 2 and psi 2 are -53.4 (6), 139.7 (4), 91.5 (5) and -62.6 (6) degrees respectively.
四苯基硼酸 N-(叔丁基羰基甘氨酰氨基乙基)-N-(乙基)铵，C11H24N3O+2.C24H20B-，Mr = 549.57，三斜晶系，P-1，a = 11.567(2)，b = 11.922(2)，c = 14.484(3)埃，α = 70.99(2)，β = 74.83(2)，γ = 59.33(1)°，V = 1613.1埃3，Z = 2，Dχ = 1.13 g cm-3，λ(Cu Kα) = 1.5418埃，μ = 4.69 cm-1，μRmax远小于1，F(000) = 592，T = 293 K，对于3491个观测反射，R = 0.058。该假肽通过一个短的N(+)-H...O = C氢键(N3...O1 = 2.81埃)折叠，形成一个十元环。这导致了一种β-转角结构，根据N端甘氨酸的构象角可归类为II型。构象角φ1、ψ1、φ2和ψ2分别为-53.4(6)、139.7(4)、91.5(5)和-62.6(6)°。
