Structure of 1,4-dioxa-10,13-dithia-7,16-diazacyclooctadecane-6,17-dione

Synthesis, NMR Studies and Crystal Structure of Cryptand 4,7,10,16,21-Pentaoxa-1,13-diazabicyclo[11.5.5]tricosane, [H(3.1.1)·(H2O)3]Cl

“…This plane has a dihedral angle of 90.2°(3) with the plane defined by N1, O16, and N13 of the other bridging segment. The torsion angle sequence for the X-C-C-Y segments (X, Y = O, N) around this 18-membered ring is (aga) 6 , where g and a indicate gauche and antiperiplanar torsion angles, respectively [21,22]. This conformation has alternating heteroatoms on opposite sides of the heteroatom plane (i.e., N1,N13,O7 and O4,O10,O21).…”

Methyl 3-(2-oxobenzothiazolin-3-yl)propanoate

“…The C7ÐN1, C7ÐS1, and C1ÐS1 bond lengths [1.371 (2), 1.768 (2) and 1.742 (2) A Ê , respectively] are approximately midway between the corresponding standard values for single and double carbon±nitrogen (1.49 and 1.27 A Ê ; Clayden et al, 2001) and carbon±sulfur (1.81 and 1.61 A Ê ; Khan et al, 1988) bonds. The C7ÐN1 bond length is in good agreement with the reported values of 1.365 (3) A Ê for 3-methyl-2(3H)-benzothiazolone (Rudd & Barany, 1984), 1.367 (2) A Ê for 4-(2carboxybenzoyl)-2(3H)-benzothiazolone (Lamiot et al, 1995), and 1.375 (3) A Ê for ethyl 4-(2-oxobenzothiazolin-3-yl)butanoate (Baysen et al, 2002).…”

(6R*,16R*)-9,14-Dihydro-6-methyl-6,16-methano-6H,16H-[2,4]benzothiazepino[3,4-d][1,3,5]benzoxadiazocine hydrobromide dimethylformamide hemisolvate

“…These data are consistent with %-electron delocalization from N19 into the protonated atom N8, leading to dispersion of the positive charge over both N atoms of the pyrimidine ring. The conjugation is extended to the S atom, as indicated by the non-equivalence of the two CÐS bond distances (Table 1); while S10ÐC11 is essentially a single bond, the C9ÐS10 distances of 1.715 (8) (molecule A) and 1.742 (9) A Ê (molecule B) correspond to a bond order of ca 1.5 (Khan et al, 1988), assuming values of 1.81 and 1.61 A Ê for single SÐC and double S C bond lengths, respectively. As a result of this conjugation, atoms C7, N8, C9, S10, C11, C18, N19 and C20 in the central part of the molecule are essentially coplanar [r.m.s.…”