Arsonic acid derivatives

It has already been noted that the esters of arsinous and arsonous acids disproportionate of heating. The formation of As(OR)3 in the pyrolysis of arsonic acid derivatives is thought to be the product of the secondary disproportionation reaction of the primary product RAs(OR)2-... 

Several methods are available for the synthesis of cycloarsoxanes (a) hydrolysis of organoarsenic(III) dihalides RASX2 (X = Cl, Br, I), (b) reduction of arsonic acids RAsO(OH)2 and (c) oxidation of primary arsines RASH2 or cyclopolyarsines (RAs) . The tetramer cyclo-(MeAsO)4 exhibits the boat-chair conformation, whereas the mesityl derivative cyclo-(MesAsO)4 adopts the crown conformation (Figure 11.24). The As-O bond distances are in the range 1.77-1.82 A, typical for single bonds. 

Aminophenylar sonic Acid or Aminobenzene-arsonic Acid, HaN C6H4 0 As(0H)a. Its o-, m- and p-isomers are known the para is of interest hecause its dinitro deriv is explo-... 

This compd is probably expl, yet not reported as such. Its methyl deriv is ex pi although its NOj-nitrogen content is smaller (See 3i5-Dinitro-4-methyl ami nophenyl arsonic Acid under Methyl ami no phenyl-arsonic Acid)... 

They are still used in the treatment of other parasitic infections. Thus, derivatives of benzene arsonic acid, CsHsAsOfOH, such asiV-acetyl-4-hydroxy-m-arsanilic acid, Af-carbamoylarsanilic acid and its oxide, sodium -(carbamoyl-methyl) arsanilate and glycobiarsol (18) are potent intestinal amoebicides when taken orally, and difetarsone (19) has recently found use as an anthelminthic29. They are also administered in the treatment of trypanosomiasis and helminthiasis in animals, as well as in topical application to destroy Trichomonas vaginalis and moni-linia. For the first of these purposes they have been largely replaced by melarsoprol... 

Arsonic acids may be regarded as derived from orthoarsenic acid, (HO)3As—>0, by replacement of one of the hydroxyl groups with an organic residue the arsinic acids are similarly derived by replacement of... 

RAs(OH)2 for arsonic acids and R2A8—OH for arsinic adds. The neutral arsine oxides, R3As—>0, may be considered as derivatives in which all the hydroxyl groups have been replaced by organic residues. 

Figure 19. Formation of cyclic disulfide derivative of 2-chlorovinyl arsonous acid using 3,4-dimercaptotoluene (16)...

Some organic derivative names still contain the word acid , as in the following derivatives of arsonic acid (H2AsH03 or [AsHO(OH)2]). 

The name in Example 4 regards the compound as derived from arsonic acid, by substitution of a phenyl group for the hydrogen atom bound directly to arsenic. The name in Example 5, in addition to the hydrogen substitution, involves functional replacement nomenclature (Section IR-8.6). 

Tetrakis(diiodoarsinomethyl)methane (292) <86ZN(B)863> on hydrolysis gives the arsonous acid (293) of the trioxatriarsaadamantane <87J0M(336)323>. The crystal structure of the deuterated derivative (-As(OD)2) was solved by x-ray diffraction analysis. There is evidence for the existence of two... 

The main application of mercury derivatives has been to the synthesis of heterocyclic arsenicals. Thus diphenylene oxide-1-arsonic acid and pyridyl-3-arsonic acid have been isolated following oxidation of the initial reaction products obtained from arsenic trichloride and the appropriate heterocyclic mercury chloride 114,115). Furan and thiophene derivatives have been similarly prepared 116,117,118). 

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