Drawing rings

Up to now, we haven t given an entirely accurate impression of rings. We have been drawing them all as if they were planar—though this is actually not the case. In this section you will learn how to draw rings more accurately and to understand the properties of the different conformations adopted. 

Fig.1 Example of CVD coated steel tool, drawing ring. (Courtesy of VST Verschleiss Schutz Technik Keller GmbH Co. KG, Schopfheim, Germany).

Forming tools such as drawing rings, deep drawing dies or bending tools for sheet metal forming are typical examples of C VD-coated steel... 

Fig. 21 Tool costs for uncoated (dashed line) and CVD coated (solid line) D2 drawing rings (schematically).

Figure 5.30. Coriformational drawing rings A and B of oxytetracycline base. When ring A adopts the half-boat arrangement shown, the dihedral angle between 4-H and 4a-H is approximately 180°.

We draw ring structures as if the rings are flat, i.e., as if all the carbon atoms of the ring lie in the same plane. This is approximately correct for the 3-, 4-, and 5-membered rings. It is incorrect for the 6-membered and larger-sized rings which exist in a puckered, nonplanar shape. The 6-membered cyclohexane ring exists in the shape referred to as the chair conformation ... 

A single bond is the basic bond created by DRAW, RING (and the item GROUP not yet considered). The BOND option allows the user to select a bond type from the BOND sub-menu and change the nature of any explicit, non-aromatic bond in the structure to the selected type. The endpoints of the bond to be altered are accessed by the mouse after a bond type has been selected. A dotted bond type can be used for limited description of stereo arrangement. A bond-erase feature is built into the sub-menu and is obtained by selecting bond-type zero. Examples of the different bond-types appear in Figure 1. 

In the most simple case during the first draw, a hollow body or a cup shape is produced from a plane sheet metal blank (irregular or circular outline of blank. Fig. 2). The deep drawing tool ever consists of three major components deep drawing punch, draw ring or die or matrice, and a blank holder. 

The radial stress Gr reaches its maximum value near draw ring radius and decreases to... 

Rather, a ring flip is a conformational change that is accomphshed only through a rotation of all C—C single bonds. This can be seen with a Newman projection (Figure 4.26). Lets get some practice drawing ring flips. 

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