ChemInform Abstract: Three Cycloadducts Formed by the Reaction of Bis(phenylazo)stilbene with Acetylenic and Olefinic Dipolarophiles (original) (raw)

cis-6,11,17,18-Tetrahydro-5,12-dioxatribenzo[a,e,i]cyclododecene-17,18-diol, C22H20O4

Acta Crystallographica Section C Crystal Structure Communications

2016 observations (of 3010 unique data). The diol O atoms form a gauche interaction with O-CC -O torsion angle, 42.5 (3) ° , smaller than that in related compounds. Both intramolecular and intermolecular hydrogen bonding are present. lntroduetlon. During the course of our studies preparing stilbene cycles as backbones for intramolecular reactions (Tirado-Rives, Oliver, Fronczek & Gandour, 1984), the title compound has been isolated and its crystal structure has been determined.

endo,endo,endo-9,9,10,11,12-Pentabromotricyclo[6.2.2.0^2,7]dodeca-2(7),3,5-triene

Acta Crystallographica Section E-structure Reports Online, 2002

4-Bromo-4′-(dimethylamino)stilbene

Acta Crystallographica Section E Structure Reports Online, 2009

Key indicators: single-crystal X-ray study; T = 123 K; mean (C-C) = 0.012 Å; R factor = 0.075; wR factor = 0.213; data-to-parameter ratio = 18.1.

Dibenzo[a,e]pentacyclo[12.2.1.1^6,9.0^2,13.0^5.10]octadeca-2(13),5(10)-diene

Acta Crystallographica Section E-structure Reports Online, 2011

The central 8-ring of the title compound adopts the boat configuration, and the overall shape of the molecule is that of a saddle. Relative to the mean plane of the saddle seat (C07, C08, C15, C16, δ r.m.s. = 0.014 Å), the two bicycloheptane moieties (mean planes C07, C08, C22, C24, δ r.m.s. = 0.001 Å, and C15, C16, C17, C19, δ r.m.s. = 0.000 Å) bend up 33.36 (5)° and 34.22 (4)°, while the mean planes of the benzo moieties (C01-C06, δ r.m.s. = 0.008. and C09-C14, δ r.m.s. = 0.013 Å) bend down 33.48 (4)° and 36.58 (4)°. S2. Experimental The preparation is described by Schaller (1994). Suitable crystals were obtained by recrystallization from benzene. S3. Refinement All H atoms were placed in calculated positions, guided by difference maps, with C-H bond distances 0.95 (aromatic C) and 0.99 (alkyl C) Å, and U iso =1.2U eq , thereafter refined as riding. supporting information sup-2 Acta Cryst. (2011). E67, o3209

Formation and crystal structure of a novel azabishomotwistane

The Journal of Organic Chemistry, 1990

solved in 10 mL of a 1O:l DMSO/water solution in a 25-mL round-bottom flask equipped with a reflux condenser, and the solution is heated in an oil bath at 80 "C for 30 min. After cooling, the solution is diluted with water and extracted with diethyl ether. The organic layer is thoroughly washed with water to remove all traces of DMSO and dried. After careful concentration of a rotary evaporator, pure nitrocyclopropane is obtained.14 Cyclopropanes 10, 11,13, and 14 are nonvolatile and are easily separated by flash column chromatography (ether/hexane, 0 4 % ) .

Phenyl 3,5-di-tert-butyl-2-hydroxybenzoate

Acta Crystallographica Section E Structure Reports Online, 2010

Benzoate phenyl esters have been described to be precursors of benzimidazole molecules by reaction with 1,2-phenylenediamine (Moore et al., 2008). The crystal shows two independent but very similar molecules within the asymmetric unit. For both independent molecules, the carboxylic acid group from ester is coplanar with the central core, as reflected by the small CC -O-C torsion angles (C1-C7-O3-C16, 179.95 (17)°; C22-C28-O6-C37 173.70 (17)°), while the phenyl substituent is almost perpendicular to the carboxylate CO 2 fragment (C7-O3-C16-C21 110.4 (2)°; C7-O3-C16-C17-74.1 (3)° and C28-O6-C37-C38-69.2 (3)°; C28-O6-C37-C42 117.4 (2)°). The coplanarity between the central aromatic ring and the carboxylate CO 2 group from ester allows the definition of a intramolecular hydrogen bond, with O•••O 2.563 (2) and 2.604 (2) Å. The structure is closely related to that of the unsubstituted 2-hydroxybenzoic acid phenyl ester (Baptista, 1966; Bilgram et al. 1982; Hammond et al., 2002), where the carboxylate group is almost coplanar to the phenyl ring where is attached (C-CO -C less than 2° deviated from 180°) and the benzoate phenyl almost perpendicular to the carboxylate (C-O-CC 75.8° and-100.5°). The phenyl rings from the benzoate from each of the two molecules within the asymmetric unit defines a weak π•••π interaction with Cg 1 (C16, C17, C18, C19, C20, C21)•••Cg 2 (C37, C38, C39, C40, C41, C41) 3.903 (2) Å]. S2. Experimental The compound was prepared by methods described in literature (Benisvy et al., 2004) slighty modified by using CHCl 3 for crystallization instead of pentane. The title compound was prepared in a 40% yield. S3. Refinement The H-atoms positions were calculated after each cycle of refinement using a riding model for each structure, with C-H distances in the range 0.93 to 0.96 Å. U iso (H) values were set equal to 1.5U eq of the parent carbon atom for methyl groups and 1.2U eq for the others. The hydroxyl hydrogen atoms were located in the difference Fourier map, but were subsequentely refined with constraints, O-H 0.82 Å and U iso (H) 1.5U eq of the parent oxygen atom. supporting information sup-2

Control of the Intramolecular [2+2] Photocycloaddition in a Bis-Stilbene Macrocycle

The Journal of Organic Chemistry, 2009

The intramolecular [2+2] photocyclization of a bis-stilbene macrocycle was studied. The reaction can be controlled by the insertion and removal of urea protecting groups. Upon UV-irradiation in both the solid state and DMSO solution, the free urea macrocycle undergoes a cis-trans photoisomerization that is followed by a [2+2] cycloaddition to afford a single product in high yield. The presence of the triazinanone urea protecting groups does not alter the cistrans photoisomerization but greatly decreases the selectivity of the photocycloaddition step.