(organic chemistry)
A polycyclic compound containing a carbon atom which is a member of two rings.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(also spirane), any of the compounds having one carbon atom or, more rarely, one atom of another element, such as Si, P, or As, common to two rings. The methods for obtaining spirans are based for the most part on the cyclization of bifunctional derivatives, in which both hydrocarbon residues containing functional groups are joined to the same atom in a ring. An example of this process is seen in the reaction

1 ,l-Bis-(methyl bromide)-cyclohexane Spiro [2.5] octane

Since the joined rings lie in mutually perpendicular planes, asymmetrically substituted spirans can be separated into optical antipodes.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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The other is a mingling of good sorts of wine in their vineyards, for they seldome make red wine of red grapes alone; it will be too thick & deepe coloured except the spiran which, they say, will make good wine by its self, but to make their red wine pleasant & delicate, they use to mingle a good quantity of white grapes with the red.