Order of precedence

Cahn-Ingold-Prelog notation (Section 7.6) System for specifying absolute configuration as / or S on the basis of the order in which atoms or groups are attached to a chirality center. Groups are ranked in order of precedence according to rules based on atomic number. 

Rang, m. rank position quality row, tier, -folge, /. ordered series, order (of precedence). ... 

Operations in a given equation are performed in decreasing order of precedence as follows ... 

Dihexulose dianhydrides are intermolecular cyclic acetals formed by the condensation of two hexulose molecules with the elimination of two water molecules, and the formation of two linkages involving the 2- and one other position of each component. They are named4 by placing the word dianhydride after the names of the two parent monosaccharides. The order of precedence for these... 

By application of the above rules, some groups in descending order of precedence are COOH, COPh, COMe, CHO, CH(OH)2, o-tolyl, m-tolyl, p-tolyl, phenyl, C=CH, rerf-butyl, cyclohexyl, vinyl, isopropyl, benzyl, neopentyl, allyl, n-pentyl, ethyl, methyl, deuterium, and hydrogen. Thus the four groups of glyceraldehyde are arranged in the sequence OH, CHO, CH2OH, H. 

Thus the absolute configuration of A is R and it follows that its mirror image B must be S (the order of precedence moves anti-clockwise). 

When tliere is a choice between two parent compounds possessing the same number of silicon atoms, the order of precedence is siloxanes. sillhianes, silazanes. and silanes. Examples ... 

The alphabetical order of precedence is preferred for substituents of different types when two or more are attached to a hydrocarbon chain because this makes indexing and using indexes more straightforward ... 

There are no simple rules to follow that dictate which is the parent function, and we suggest that the order of precedence of functional groups set by Chemical Abstracts be used whenever possible (see Table 7-1). By this system, the OH group takes precedence over hydrocarbons, and Compound 1 therefore is named as an alcohol, not as an alkene. 

Exercise 7-2 Translate each of the following structures into the proper IUPAC name. Take cognizance of the order of precedence in Table 7-1 and use alphabetical order in citing substituent groups. 

An order of precedence is established for the two atoms or groups attached to each end of the double bond according to the sequence rules of Section 19-6. When these rules are applied to l-fluoro-l-chloro-2-bromo-2-iodoethene, the priority sequence is ... 

When the lowest ranked substituent points away from you, the remaining three must appear in descending order of precedence in a counterclockwise fashion in the S enantiomer. ( S )- 1, 1-difluoro-2-methylcyclopropane is therefore... 

Professor Dupont, in a letter of March 5, 1952, expressed the opinion that the numbering in going from bicyclics to monocyclics should be preserved as much as possible — for example, for the transformation pinene —> limonene, it would be useful to preserve the numbering. This would be obtained if a-pinene retained its classical formula (I) and if for limonene (II) the numbering corresponded to that required for menthene on the basis of the Chemical Abstracts alphabetic order of precedence of the names of the substituents — i.e., isopropyl methyl — thus ... 

Taking the list of tasks given in the Gantt Chart for Product X the order of precedence can be drawn up. 

The equality constraints composed of the mass and heat balances and the performance equations in each subsystem, thermodynamic properties of the flows, and specifications for design are represented by the functions h which are in the form of n equations with m+n variables. These equations are easily arranged in the order of precedence based on structural analysis. The number of independent variables (parameters), y, corresponds to the degrees of freedom in the system. When the value of the parameters is given, n equations are solved with respect to n variables, z. Thereupon, the inequality constraints, if any, are checked and the objective functions are calculated. Therefore, the problem is rewritten simply as follows ... 

Staff and students forgathered in the Common Room and in order of precedence each chose a partner, senior offering an arm to juniors. Any fresher left over bought up the rear of the procession, sometimes with relief at not having to make conversational efforts.23... 

The sequence rule (also known as the Cahn-lngold-Prelog (CIP) system) is the universal system of describing absolute configurations. It provides a method of arranging atoms or groups in an order of precedence and is used to assign stereochemical descriptors, R-, S-, also E-, Z-, and others. 

To decide on the order of precedence in which this expression is evaluated, first write x as x x x to give... 

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