Molecular geometry of substituted benzene derivatives.I. On the nature of the ring deformations induced by substitution

Domenicano, Aldo; Vaciago, A.; Coulson, C. A.

doi:10.1107/s0567740875002397

Cited by 364 publications

(154 citation statements)

References 29 publications

(37 reference statements)

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“…The deformation of the phenyl ring induced by the piperidine substituent is such as to narrow the angles at the ipso and para C atoms and widen those at the ortho and meta C atoms (Table 3), in agreement with the findings of Domenicano, Vaciago & Coulson (1975). No particular trends are observed for the variations of bond distances in the ring.…”

Section: Commentsupporting

confidence: 80%

Structure and conformation of 1'-phenylindan-2-spiro-4'-piperidin-1-one

Ianelli¹,

Nardelli²,

Belletti³

et al. 1992

Acta Crystallogr C

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EAF(obs.)AF(calc.) = 10025(29), enantiomorph ~AF(obs.) x AF(calc.) = -9742(29) on 1104 Bijvoet pairs. The results indicate that the model corresponds to the correct configuration, with the same 2R,3R configuration for the tartaric moiety as that of the tartaric acid used in the synthesis.Througout this paper, the averaged values are means weighted according to the reciprocals of the largest 'external' and internal standard deviations (Topping, 1960).The calculations were carded out on the ENCORE-GOULD-POWERNODE 6040 computer of the 'Centro di Studio per la Strutturistica Diffrattometrica del CNR (Parma)'. In addition to the quoted programs, LQPARM (Nardelli & Mangia, 1984), PARST (Nardelli, 1983a), and ORTEP (Johnson, 1965) were also used.Acta Cryst. (1992 AbstractThe title compound was obtained, amongst other products, by the condensation of quinuclidinone enolate with bromobenzene in the presence of the NaNH2.tBuONa complex base. X-ray analysis proved the only way of successfully identifying its structure. Its formation suggests a new mechanism of arynic condensation. The spiro addition of piperidine to the indanone system does not modify the geometry of the two moieties significantly. It is possible that some degree of conjugation between the N lone pair and the phenyl 7r system determines the conformation about the N--Ph bond, which itself seems mainly influenced by packing interactions. CommentThe condensation of ketone enolates with aryl halides in the presence of NaNH2.RONa complex bases is now a well established procedure which allows the synthesis of a wide variety of compounds (Caub6re, 1974;Carr6, Jamart-Gr6goire, Geoffroy, Caub6re, Ianelli & Nardelli, 1988, and references cited therein). In order to develop research into this kind of reaction, we have been studying the condensation of ketones containing functional groups for some time. As part of this work, we carded out the condensation of the enolate of quinuclidinone with bromobenzene.Amongst the products isolated was one that we were unable to identify by the usual spectroscopic methods and

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Section: Commentsupporting

confidence: 80%

Structure and conformation of 1'-phenylindan-2-spiro-4'-piperidin-1-one

Ianelli¹,

Nardelli²,

Belletti³

et al. 1992

Acta Crystallogr C

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“…3 are about 0.006 A and 0.4 ° The C-C distances are closely equal in all three forms of TMA that have been studied (Table 7). The average C-C(external) distance, 1.487(1) A, is slightly smaller than the value 1.491 (1) A obtained by Domenicano, Vaciago & Coulson (1975, …”

Section: Tma~h20mentioning

confidence: 64%

The crystal structures of trimesic acid, its hydrates and complexes. II. Trimesic acid monohydrate–2/9 picric acid and trimesic acid 5/6 hydrate

Herbstein¹,

Marsh²

1977

Acta Crystallogr Sect B

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(Mo Ka', 2840 and 6768 non-zero reflections respectively). In TMA. H20.~PA there are hydrogen-bonded layers of-composition TMA .H20 in the (i i 1) planes; these layers are pierced by channels along [001] containing the picric acid molecules. Diffuse X-ray scattering by these crystals suggests that the enclathrated pictic acid molecules have only a short-range coherence with the TMA .HzO layers. TMA.5H2 O contains very similar layers of TMA. HzO in the (100) planes; the five such layers in the [I00] repeat are offset such that the channel takes on a zigzag shape in order to accommodate zigzag ribbons of TMA molecules (two per cell), hydrogen bonded through the carboxyl groups in the 1-and 3-positions. The enclathrated TMA molecules are strictly ordered with respect to the TMA. H20 framework. Introduction ExperimentalWe report here the crystal structures of two hydrates of trimesic acid (TMA) that were uncovered during a survey of TMA compounds. The two structures are similar, both being based on a planar framework of hydrogen-bonded TMA and water molecules, with the planar arrays stacked so as to form channels containing guest molecules. In one structure, with empirical formula TMA.]H20, the channels are occupied by additional TMA molecules in an ordered array; in the other, TMA.H20.~-PA (PA = picric acid), the PA molecules occupy the channels in a disordered fashion. Both structures are somewhat unusual. TMA.~H20 contains 12 molecules of TMA and 10 water molecules per unit cell, in space group P1; in the picric acid complex, the chain of PA molecules has a different periodicity from the host framework, leading to additional, diffuse layer lines. Accordingly, we report the structure solutions and refinements in some detail. TMA.H20.2pA was obtained by recrystallization of 25 ml of an aqueous solution containing a total of 4.3 mmol of TMA plus PA. When the TMA:PA ratio in these solutions was 3:1, the predominant product was orthorhombic crystals of TMA.~4PA, together with some straw-colored triclinic needles of TMA.H20.2pA; when the ratio was 1"2, the latter crystals predominated. The composition of these triclinic needles did not appear to vary with the composition of the parent solution, since identical diffraction photographs were obtained from different preparations.Unit-cell dimensions for both crystals were measured from back-reflection Weissenberg photographs about all three axes, with Cu Ka radiation. The density of TMA.]HzO was measured by suspension in tolueneC2H4Br 2 solution, and that of TMA.H20.~PA by suspension in a CCl4-toluene solution. Crystal data are collected in Table 1. Chemical analyses of both compounds were carried out by Galbraith Laboratories. Crystals of TMA.H20.~PA give a diffraction pattern consisting of two components: (1) the Bragg (sharp) reflections that characterize the unit cell described in Table 1 and (2) a series of diffuse reflections which we ascribe to the PA molecules being ar- Table 1 ranged without long-range order but with a considerable degree of short-range order (Fig...

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“…This plane forms an angle of 5.5(2)8 with that calculated for ring A. The weighted average absolute torsion angle [16] in the ring C is 29.2(2)8. The phenyl ring B has also a planar conformation with O(7) (deviation of 0.010(6) ) coplanar to it.…”

mentioning

confidence: 87%

Structure and Vasorelaxant Activity of Floranol, a Flavonoid Isolated from the Roots ofDioclea grandiflora

Lemos

Côrtes

Santos

et al. 2006

C&B

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The structure of the prenylated flavanonol, floranol (1 ¼ (2R,3R)-3,5,7-trihydroxy-2-(2-hydroxyphenyl)-6-methoxy-8-(3-methylbut-2-enyl)-4H-1-benzopyran-4-one), isolated from the roots of Dioclea grandiflora (Fabaceae), was unambiguously determined by X-ray analysis. The compound was tested for vasorelaxant activity. In endothelium-containing aortic rings, floranol (1) induced a concentrationdependent vasodilator effect in vessels precontracted with 0.1 mm phenylephrine with an IC 50 value of 19.9 AE 2.4 mm. The removal of endothelium or pretreatment of vessels with the NO-synthase inhibitor l-NAME did not change the IC 50 and E max values for floranol-induced vasorelaxation. We conclude that floranol (1) should be acting directly in the rat-aorta smooth muscle cells to produce its vasorelaxant effect. The structure -activity relationship was discussed in terms of the 3-D floranol structure determined by X-ray crystallography.

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Molecular geometry of substituted benzene derivatives.I. On the nature of the ring deformations induced by substitution

Cited by 364 publications

References 29 publications

Structure and conformation of 1'-phenylindan-2-spiro-4'-piperidin-1-one

Structure and conformation of 1'-phenylindan-2-spiro-4'-piperidin-1-one

The crystal structures of trimesic acid, its hydrates and complexes. II. Trimesic acid monohydrate–2/9 picric acid and trimesic acid 5/6 hydrate

Structure and Vasorelaxant Activity of Floranol, a Flavonoid Isolated from the Roots ofDioclea grandiflora

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