Ortho arrangement

Answer it can be easily discerned that the ortho arrange-. ment of the -OH and -OHO groups in XIII-c lends itself very readily to the Reimer-Tiemann reaction. If we desire to place the formyi group on the ring in the last step, this would require compound A. 

The regiochemistry of the Diels—Alder reaction can then easily be predicted by a careful match of the charges. If an EDG is located at C-1 of a diene, then the dienophile will approach with the EWG group next to the EDG group. This is called a 1-2 or ortho arrangement of the substituents (Scheme 4.15). 

If available, molecular structure and CAS number are represented. The molecular structure of the polymer is related to the vibrational modes. Carbon and hydrogen atoms of an aromatic unit are mostly not indicated. Polymers or structural units of polymers that can have a para-, meta-, or ortho-arrangement are drawn in the para-arrangement. The headline and structure of tables is shown in Fig. 12. 

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