Antimony synthesis

The standard synthesis method features side-chain chlorination of a methylpyridine (picoline), followed by exchange-fluoriaation with hydrogen fluoride or antimony fluorides (432,433). The fluoriaation of pyridinecarboxyHc acids by sulfur tetrafluoride (434) or molybdenum hexafluoride (435) is of limited value for high volume production operations due to high cost of fluorinating agent. 

The classical synthesis iavolves the dissolution of a 33% Sb—67% Zn alloy by hydrochloric acid the evolved gases contain up to 14% stibiae. A detailed procedure usiag a Sb—Mg alloy has also beea described (16). Aluminum hydride or alkaU metal borohydrides have been used to reduce antimony(III) ia acidic aqueous solutioa to produce stibiae. A 23.6% yield of stibiae, based oa the borohydride used, has beea reported (17). A 78% yield based oa Sb has beea obtaiaed by gradually adding a solutioa that is 0.4 Min SbCl and saturated ia NaQ, to aqueous NaBH at mol ratios of NaBH iSbQ. >10 (18). 

Stibonium Ylids and Related Compounds. In contrast to phosphoms and arsenic, only a few antimony yhds have been prepared. Until quite recendy triphenyl stibonium tetraphenylcyclopentadienyUde [15081 -36-4] C H Sb, was the only antimony yUd that had been isolated and adequately characteri2ed (192). A new method, uti1i2ing an organic copper compound as a catalyst, has resulted ia the synthesis of a number of new antimony yhds (193) ... 

Fluorination and iodination reactions are used relatively littie in dye synthesis. Fluorinated species include the trifluoromethyl group, which can be obtained from the trichi oromethyl group by the action of hydrogen fluoride or antimony pentafluoride, and various fluorotria2iQyl and pyrimidyl reactive systems for reactive dyes, eg, Cibacron F dyes. 

A one-pot synthesis of alkyl perfluoroalkyl ketones has been developed. Phosphoranes, generated in situ, are acylated with a perfluoroacyl anhydnde, and the resultmg phosphonium salts are hydrolyzed with alkali [4S (equation 48) Hydrolysis of a carbon-sulfur bond in 2-chloro-2,4,4-trifluoro-1,3-dithietane-S-trioxide, which can be obtained from 2,2,4,4-tetrachloro-l,3-dithietane by fluor-mation with antimony trifluoride followed by selective oxidations, opens the nng to produce 2-chloro-1,1,2-trifluorodimethyl sulfone [49] (equation 49)... 

Covalent fluondes of group 3 and group 5 elements (boron, tin, phosphorus, antimony, etc ) are widely used m organic synthesis as strong Lewis acids Boron trifluoride etherate is one of the most common reagents used to catalyze many organic reactions. A representative example is its recent application as a catalyst in the cycloadditions of 2-aza-l,3-dienes with different dienophiles [14] Boron trifluoride etherate and other fluonnated Lewis acids are effective activators of the... 

Androcymbine, O-benzyl-, synthesis 282 Anilinium ion, as nucleophilic partner 49 f. Anthracene, trapping of arynes 187f. Antimony-de-diazoniation 275 Arenediazonium ions... 

Especially notable is also the synthesis and structural characterization of an unusual antimony(III) guanidinate. 1,2,3-Tiiisopropylguanidine, Pr N = C(NHPr )2,was found to react with 1 molar equivalent of Sb(NMe2)3 in toluene under formation of a yellow solution, from which the novel compound Sb[Pr NC(NPr )2][Pr NHC(NPr )2] could be isolated in 10% yield as highly air-sensitive crystals. In the solid state, the complex adopts a heavily distorted trigonal-bipyramidal molecular structure in which the Sb is chelated by a [CfNPr ls] dianion and a [Pr NHC(NPr )2] monoanion (Figure 16). Supramolecular... 

Scheme 14 Synthesis of antimony polysulfido complexes from the corresponding antimony dihydride...

Mossbauer spectroscopy is a specialist characterization tool in catalysis. Nevertheless, it has yielded essential information on a number of important catalysts, such as the iron catalyst for ammonia and Fischer-Tropsch synthesis, as well as the CoMoS hydrotreating catalyst. Mossbauer spectroscopy provides the oxidation state, the internal magnetic field, and the lattice symmetry of a limited number of elements such as iron, cobalt, tin, iridium, ruthenium, antimony, platinum and gold, and can be applied in situ. 

The ECALE synthesis of V-VI (V Sb, Bi) compounds has been attempted in a few works. Antimony telluride, Sb2Te3, nanofilms with a homogeneous microstructure and an average size of about 20 nm were formed epitaxially on a Pt substrate [61]. The optical band gap of these films was blue-shifted in comparison with that of the bulk single-crystal Sb2Tc3 compound. 

The only references of antimony available in the literature were the reactions in ethanolic solutions. Nowak et al. [133] have reported the sonochemical synthesis of SbSI gel by irradiating an ethanolic solution containing elemental antimony, sulfur and iodine for 2 h by the ultrasound of 35 kHz and 2 W/cm2 at 50°C. They also... 

Synthesis and Reactivity of Conjugated and Nonconjugated Rings Containing Arsenic, Antimony, and Bismuth... 

CHEC-II(1996) comprehensively outlines the most commonly used synthetic approaches applied to these types of bicyclic compounds of phosphorus, arsenic, antimony, and bismuth <1996CHEC-II(8)863>. The six classes of compounds listed in this section have received considerable attention over the review period and as such the principal synthetic methods for these compounds are discussed. Schoth et al. <2000CCR101> have reviewed the use of fluorinated 1,3-diketones, 2-trifluoroacetylphenols, and their derivatives in the synthesis of phosphorus compounds. Included in this review is the use of these reagents for the synthesis of various [3.3.1] nonfused and [3.3.0] fused phosphorus bridgehead bicyclic systems. 

Enamines 187 with electron-withdrawing groups in the /3-position are converted into thiadiazoles 188 in moderate yields (50-60%) on treatment with either tetrasulfur tetranitride antimony pentachloride complex <2000H(53)159> or trithiazyl trichloride <2001J(P1)662> (Equation 38 Table 12). Cyclization onto electrophilic /3-substituents was not observed, and thus the procedure offers a regiospecific synthesis of 4-substituted-3-aroyl-l,2,5-thiadiazoles. 

Table 9.63 Synthesis of allenylcarbinols from a propargylic antimony reagent.

In most oases, the fluoro Pummerer reaction can be carried out with 1.33 to 2.0 equiv of DAST and a "catalytic" amount of antimony trichloride in either refluxing methylene chloride or chloroform at room temperature or 50°C. In the synthesis of fluoromethyl phenyl sulfide, however, the induction period makes room temperature conditions the preferred method for large scale synthesis. 

Electron-withdrawing groups decrease the rate of the fluoro Pummerer reaction, which, in certain cases,7 allows a DAST-mediated deoxygenation to compete with the introduction of fluorine alpha to sulfur. The reaction is compatible with a number of functional groups and can readily be carried out with nucleosides. Robins and coworkers4 reported the synthesis of a 5 -fluoro-5 -S-phenyladenosine analog using antimony trichloride as catalyst at room temperature. It should be noted that a-fluoro sulfoxides provide a convenient entry to terminal fluoroalkenes.3 8 9 10... 

The synthesis of stable complexes with transition metal-phosphorus triple bonds is of fundamental importance and opens a novel chapter of a special field of coordination chemistry. The synthesis of analogous complexes with ligands of the heavier homologues like arsenic has partially been carried out [6], while for antimony and bismuth, the elusive M=Sb and M=Bi systems have now moved within reach. Moreover, the experimental and theoretical... 

Inductive effects can have very pronounced effects on the reactivity of amides and similar substrates towards nitrolysis. Chemists at the Naval Air Warfare Center (NAWC) have reported an extreme case encountered during the synthesis of the energetic 1,5-diazocine known as HNFX (86). A key step in this synthesis involves a very difficult nitrolysis of the electron deficient N-nosyl (4-nitrobenzenesulfonyl) bonds of (85). Nitrolysis with strong mixed acid requires a temperature of 70 °C for 6 weeks to achieve a yield of 16 %. The same reaction with nitric acid-triflic acid requires a temperature of 55 °C for 40 hours to achieve a 65 % yield of HNFX. The same chemists reported a similar case of N-nosyl bond nitrolysis which needed a nitrating agent composed of nitric acid-triflic acid-antimony pentafluoride. ... 

Phosphorus, arsenic, and antimony donor ligands. A general synthesis has been reported for trialkyl phosphite complexes of noble metals, including [RuLeJ, [RuXLsl, and [RuHLs]+ [L = P(OMe)3 or P(OEt)3 X = Cl or Br]. The complexes were isolated as their tetraphenylborate salts from reaction of the phosphite with methanolic solutions of suitable labile olefin... 

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