4-chloroindole acetic acid

During seed development auxins accumulate in the nutritive tissues, i.e. in the endosperm and nucellus. This was shown firstly for the cereals (e.g. rye [78]) and later for apple [107] and garden pea [51] among others. In the garden pea the auxin produced in the endosperm was found to be 4-chloroindole acetic acid, whereas its methyl ester occurred mainly in the embryo [65]. The auxin extractable from the seed tissues is almost certainly produced there, presumably by the biosynthetic pathway which has been worked out from studies on other parts of higher plants. These have shown that lAA is derived from the amino acid tryptophan, by the route shown in Figure 3.28. Further details can be found in recent reviews (e.g. [158]). 

Indole -3-acetic acid 4—chloroindole acetic acid (ClAA)... 

Jensen JB, H Egsgaard, H van Onckelen, BU Jochknsen (1995) Catabolism of indole-3-acetic acid and 4- and 5-chloroindole-3-acetic acid in Bradyrhizobium japonicum. J Bacterial 111 5762-5766. 

Chloroindole has been prepared from indole and sulfuryl chloride (66JOC2627) and 3-bromo- and 3-iodo-indole have been obtained by direct halogenation in DMF (82S1096). 2-Methylindole reacts with sodium hypochlorite in carbon tetrachloride to give a 2 1 mixture of 1,3- and 3,3- dichloro derivatives (81JOC2054). 3-Substituted indoles are halogenated to yield 3-haloindolenium ions which react in a variety of ways, as illustrated by the reaction of 3-methylindole with NBS in aqueous acetic acid (Scheme 12). 

The treatment of isatin with sodium hypochlorite in acetic acid leads to 1-chloroisatin, an effective mild oxidizing agent for the conversion of alcohols to aldehydes and ketones110 and of indoles to 3-chloroindoles without formation of by-products111. N-[phenyliodine(III)] bisisatin can be obtained from the sodium salt of isatin and phenyliodine (IE) bistrifluoroacetate in 85% yield. This compound is a member of a group of iodine(III)imides,... 

In 1926 Frits Went, a student in the Netherlands, detected that the tips of wheat seedlings contained a substance that caused the seedlings to bend toward the light. The identity of the substance, which was given the name auxin from the Greek auxein (meaning "to increase"), was unknown. A few years later it was shown that auxin was indole-3-acetic acid (I A A). Today, four natural auxins are known. Besides IAA there are indole-3-butyric acid, phenylacetic acid, and 4-chloroindole-3-acetic acid. (It is quite interesting to find a chlorinated aromatic substance as a natural substance. It is synthesized... 

The natural auxins indole-3-acetic acid, 4-chloroindole-3-acetic acid, phenylacetic acid, and indole-3-butyric acid... 

Yields of 3-chloroindoles reach 90% while performing the reaction under nitrogen and decrease considerably in acetic acid in the presence of oxygen. Under these conditions together with chloroindoles the products of oxidation and dimerization are formed (Scheme 49). 

Chloroindole-3-acetic acid and indole-3-butyric acid in plants... 

Indole is chlorinated with SOCI2 or aqueous NaOCl to give 3-chloroindole, and 3-bromoindole is formed with W-bromosuccinimide. Action of HNO3 indole causes oxidation of the pyrrole ring followed by polymerization. Indoles substituted in the 2-position react with HNO3 in acetic acid to give 3,6-dinitro compounds. Sulfonation of indole with pyridine-S03 complex leads to the formation of indole-3-sulfonic acid. 

The highly substituted indole, ecopladib (82), which shares many structural elements with the phospholipase inhibitor varespladib (37), shows similar biological activity. Alkylation of hydroxy benzoate (72) with the dimethyl acetal from bromoacetaldehyde (73) affords the ether (74). Acid-catalyzed reaction of this intermediate with 2-methyl-5-chloroindole (75) in the presence of triethylsilane leads in effect to condensation of the acetal with the activated 3 position on the indole ring to afford 76. The nature of the reduction of the aldehyde carbon is not immediately apparent. Alkylation of the anion on nitrogen from reaction of the indole with sodium hydride and bromodiphenylmethane then adds the third... 

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