Crystal Structure of N-tert-Butoxycarbonylbis(2-thioacetoxyethyl)amine

donor macrocycles is an intensive area of study.1 One strategy for the synthesis of the macrocycles based on an NS2-donor set involves the title compound (Fig. 1) as a large scale precursor, followed by cyclization and deprotection of tert-butoxycarbonyl (Boc) group. During our search for new macrocycles containing NS2Xn (X = O or S, n = 1 – 2) mixed-donor atoms, the title compound was synthesized in our laboratory from the reaction of the N-Bocbis(2-chloroethyl)amine2 and potassium thioacetate. The synthetic procedures will be described elsewhere.3 Single crystals suitable for X-ray crystallography were grown by slow evaporation from ethylacetate/hexane (1:9) at room temperature. The crystal and experimental data are given in Table 1. The structure was solved by direct methods and refined with anisotropic temperature factors for non-hydrogen atoms. All hydrogen atoms were located from difference Fourier maps and were not refined. The atomic coordinates for non-hydrogen atoms are listed in Table 2. The bond distances and angles are listed in Table 3. The molecular structure and the atomic numbering are given in Fig. 2. The molecule has a fully stretched skeleton and the torsion angles of each N-fragment correspond to the anti conformation [172.6(2) ̊ for –N–C4–C3–S1–, 178.8(2) ̊ for –N–C5–C6–S2– and 177.5(2) ̊ for –N–C9–O4–C10–]. Two thioacetate and one Boc 1287 ANALYTICAL SCIENCES NOVEMBER 2002, VOL. 18 2002 © The Japan Society for Analytical Chemistry