Iodobenzoate

The Dess-Martin periodinane ( DMP ) reagent, U,l-tris(acetyloxy)-l,l-dihydro-l,2-benziodoxol-3(l//)-one, has also been used in several complex syntheses for the oxidation of primary or secondary alcohols to aldehydes or ketones, respectively (e.g., M. Nakatsuka, 1990). It is prepared from 2-iodobenzoic add by oxidation with bromic add and acetylation (D.a Dess, 1983). 

The 2-iodobenzoate is introduced by acylation of the alcohol with the acid (DCC, DMAP, CH2CI2, 25°, 96% yield) it is removed by oxidation with CI2 (MeOH, H2O, Na2C03, pH > 7.5). ... 

Iodobenzoic acid [88-67-5] M 248.4, m 162 , pK 2.93. Crystd repeatedly from water and EtOH. Sublimed under vacuum at 100°. 

Iodosalicylic acid (2-hydroxy-5-iodobenzoic acid) [119-30-2] M 264.0, m 197 pKj 2.65, pK 13.05. Crystd from water. 

The cyclization of o-halogenobenzoic acids with copper acetylides mainly leads to the formation of five-membered lactones (66JOC4071 69JA6464) (Scheme 115). Only in the case of the reaction of o-iodobenzoic with CuC=C—n-C3H7 does the formation of a mixture of y- and 5-lactones occur (Scheme 116). 

Cyclocondensation of 2-chloronicotinic acid with 2-amino-5-iodobenzoic acid and methyl 2-amino-4-bromobenzoate in boiling EtOH in the presence of cone. HCl for 18 h gave the 2-iodo and 3-bromo derivatives of 11-0X0-1 l/f-pyrido[2,l-6]quinazoline-6-carboxylic acid (98MIP1, 98MIP2, 99USP5908840, 99USP5914327). 

Ullman condensation of m-trifluoromethylaniline (13) with o-iodobenzoic acid in the presence of copper-bronze affords flu-fenamic acid (14). An analogous reaction of o-chlorobenzolc acid with 2,3-dimethylaniline (15) gives mefenamic acid (16) meclofenamic acid (18) is obtained by Ullman condensation employing 2,6-dlchloro-3-methylaniline (17). 

Ullmann condensation of the sodium salt of p-chlorothiophe-nol (31) with 2-iodobenzoic (32) acid gives 33. Cyclization by means of sulfuric acid affords the thioxanthone, 34. Reaction with the Grignard reagent from 3-dimethylaminopropyl chloride affords the tertiary carbinol (35). Dehydration by means of acetic anhydride affords chlorprothixene as a mixture of geometric isomers, 36. (Subsequent work showed the Z isomer-chlorine and amine on the same side—to be the more potent compound.) Chlorprothixene is said to cause less sedation than the phenothiazines. ... 

Sandmeyer reaction provides access to 2-iodobenzo[h]selenophene (60MI1) the 4-iodo isomer is made from the lithium derivative (54J A5775). 

The submitters used a two-necked, round-bottomed flask equipped with a magnetic stirbar, three-way stopcock connected to vacuum and a N2 source, and a solid addition tube. The addition tube was charged with methyl 4-iodobenzoate, tris(dibenzylideneacetone)dipalladium(0), and tri-o-tolylphosphine. After the zinc reagent was formed and the ice bath was removed, the solids contained in the addition tube were added in one portion by inverting the tube. 

Methyl 4-iodobenzoate was purchased from Avocado Chemical Co. Zinc dust (< 10 microns, 95% purity) was purchased from Aldrich Chemical Company, Inc. The checkers purchased Pd2dba3 and P(o-Tol)3 from Strem Chemicals, Inc. and I2 from Mallinckrodt. The submitters purchased Pd2dba3 and P(o-Tol)3 from Aldrich Chemical Company, Inc. 

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