2-Iodophenylacetic acids

The first six-membered iodine(III) heterocycle, the cyclic tautomer of 2-iodosylphenylacetic acid, 221, was reported in 1963 by Leffler and coauthors [342]. This compound was synthesized by chlorination of 2-iodophenylacetic acid (220) followed by hydrolysis of the initially formed, unstable 2-(dichloroiodo)phenylacetic acid (Scheme 2.67). Compound 221 is stable at room temperature but decomposes in solution at 80-100 °C the proposed cyclic structure 221 is in agreement with its relatively low acidity (pXa = 7.45) [342]. 8-Iodosyl-l-naphthoic acid (222) was prepared by the peracetic oxidation of 8-iodo-1-naphthoic acid [343]. Anions of 2-iodosylphenylacetic acid (221) [328] and 222 [343] have a moderate reactivity in the cleavage of phosphate esters in aqueous micellar solution. The chiral, enantiomerically pure substituted 2-iodosylphenylacetic acid derivatives 223 and 224 were synthesized from the corresponding aryl iodides by oxidation with dimethyldioxirane [344]. 

The six-membered cyclic IBX analogues 528 have been synthesized by oxidation of the corresponding 2-iodophenylacetic acids 527. Interestingly, an X-ray structural study demonstrated that products 528 exist in the solid state as pseudocyclic acids 529 (Scheme 2.148) [345]. 

Preparation of the first example of a six-membered iodine(III) heterocycle, the cyclic tautomer of 2-iodosylphenylacetic acid 192, was reported in 1963 by Leffler and coauthors (1962JA3443). This compound was synthesized by chlorination of 2-iodophenylacetic acid 191 followed by hydrolysis of the initially formed, unstable 2-(dichloroiodo)phenylacetic acid (Scheme 41). Compound 192 is stable at room temperature but decomposes in solution at 80—100 °C the proposed cyclic structure 192 is in agreement... 

Perkin condensation of o-iodophenylacetic acid (70) with m-hemipinic anhydride... 

Polymer-supported (diacetoxyiodo)arenes 8 with a different linker have been prepared from the commercially available aminomethylated polystyrene 5 (Scheme 5.4) [18]. In the first step, the reaction of polymer 5 with 4-iodobenzoic acid (6, = 0) or 4-iodophenylacetic acid (6,n= 1) affords polymer-supported iodides... 

The ester of 3-a-cholestanol with p-iodophenylacetic acid held the iodine in such a position that an attached chlorine atom could reach the hydrogen of C-14, but not... 

What has been described as biomimetic control of chemical selectivity is already possible. When the steroid 3a-cholestanol is esterified with 4-iodophenylacetic acid and treated with chlorine in the dark the iododichloride can generate free radicals which attack the C-17 of the steroid. The shorter ester derived from benzoic acid attacks C-9 (Figure 6.33). In another context metal porphyrin complexes have been devised which can hydroxylate hydrocarbons (Figure 6.34). Many more ideas of this kind are likely to follow a better understanding of the mechanisms of enzyme catalysis. 

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