Flagpole

FIGURE 3 14 (a) A ball and spoke model and (b) a space filling model of the boat confor mation of cyclohexane Torsional strain from eclipsed bonds and van der Waals strain involving the flagpole hydrogens (red) make the boat less stable than the chair... 

Receptor height above ground (may be used to define flagpole receptors) (m)... 

In the model, a flagpole receptor is defined as any receptor, which is located above local ground level, e.g., to represent the roof or balcony of a building. 

We also performed a single-crystal X-ray structure analysis of this lead compound. The solid state structure of this compound depicted in Fig. 3-15 shows a half-boat-like ( sofa ) conformation with the 9-phenanthryl group in a quasi-axial or r/Mf/.v/-flagpole position, and the a, 3-unsaturated exocyclic ester in a s-cis conformation. This cleft-like conformation is advantageous for the creation of centers with a high recognition ability, since one enantiomer fits in better than the other thus leading to selectivity. 

Boat cyclohexane has torsional strain and flagpole interaction. 

Figure 4.15 (a) Illustration of the eclipsed conformation of the boat conformation of cyclohexane, (b) Flagpole interaction of the Cl and C4 hydrogen atoms of the boat conformation. 

By flexing to the twist conformation, the boat conformation can relieve some of its torsional strain and reduce the flagpole interactions. 

The distance between their centres at normal tetrahedral angles should have been only about 1.8 A, but the sum of the van der Waals radii of the two hydrogen atoms is 2.4A. This is sometimes called bowsprit-flagpole interaction and this too makes its contribution to the increased energy of the boat form. 

Right triangles are commonly used in conjunction with ratios to measure tall items such as trees or flagpoles. On a sunny day the sun hits all objects positioned at the same location at the same angle. 

A woman, 64 inches tall, casts a shadow that is 51.2 inches long. If the length of the shadow cast by the flagpole is 192 inches, how tall is the flagpole ... 

Fig. 9. Possible conformations of fused-ring compounds (e.g. (58)). Nitrogen atoms and ring substituents are omitted. The first two letters for each structure refer to the ring conformations (b = boat, c = chair) and the second two letters refer to the phosphorus-exo-substituent (a = axial, b = bowsprit, e = equatorial, f = flagpole)...

The radical cation (19 " ) of the strained bicyclo[2.1.0]pentane also has a puckered conformation, supported by one strongly coupled (flagpole) proton (flsyn = 4.49 mT). Ab initio calculations indicate that the transannular bond retains some bonding and that the bridgehead carbons remain pyramidal. ... 

Finally, cyclodipeptides in which both the amino acid units have aliphatic side chains have also been investigated (83BCJ1155). In the case of the cis cyclodipeptides, cyclo(L-Val)2 and cyclo(L-Leu)2, the hydro-phobic interaction between the two side chains may stabilize the planar-axial or the flagpole-boat-type conformation, respectively, in polar solvents. 

You have a fish pond on your property that s a perfect circle with a diameter of 100 feet. In the exact center of your fish pond, there s a flagpole. You want to tie a rope to that flagpole, but your rope is only 101 feet long, and you don t... 

Cyclohexane minimizes its ring strain by being puckered rather than flat. The two extreme conformations are the more stable chair and the less stable boat. The twist-boat conformer is less stable than the chair by about 23 kJ/mol, but is more stable than the boat. It is formed from the boat by moving one flagpole" to the left and the other to the right. See Fig. 9-5. 

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