Stannic chloride, hydrolysis

Stannic Chloride. Stannic chloride is available commercially as anhydrous stannic chloride, SnCl (tin(IV) chloride) stannic chloride pentahydrate, SnCl 5H20 and in proprietary solutions for special appHcations. Anhydrous stannic chloride, a colorless Aiming Hquid, fumes only in moist air, with the subsequent hydrolysis producing finely divided hydrated tin oxide or basic chloride. It is soluble in water, carbon tetrachloride, benzene, toluene, kerosene, gasoline, methanol, and many other organic solvents. With water, it forms a number of hydrates, of which the most important is the pentahydrate. Although stannic chloride is an almost perfect electrical insulator, traces of water make it a weak conductor. 

Bis(trineophyltin) oxide [60268-17-4] is prepared from the chloride in the normal manner. The chloride can either be prepared directiy from the reaction of three moles of neophylmagnesium chloride and stannic chloride or by the butyl transfer reaction between butyltrineophyltin and stannic chloride. The hydroxide derivative initially formed on hydrolysis of the chloride is readily dehydrated to the bis(oxide) at ca 100°C. 

Condensation of 3-chloromethylbenzo[6]thiophene with diethyl malonate followed by hydrolysis, decarboxylation, Arndt-Eistert homo-logization, hydrolysis, and cyclization of the derived acid chloride with anhydrous stannic chloride yielded 2-methyl-4-keto-l,2,3,4-tetrahy-drodibenzothiophene (47). ... 

Octahydrodibenzothiophene (73) has been prepared by the following sequence. Friedel-Crafts acylation of 4,5,6,7-tetra-hydrobenzo[6]thiophene with succinic anhydride (87%) or with the ester chloride of succinic acid followed by hydrolysis (80%), yields the keto acid (74). Huang-Minlon reduction of 74 followed by cyclization of the derived acid chloride with stannic chloride yields l-keto-1,2,3,4,6,7,-8,9-octahydrodibenzothiophene (53) (Section V,A). Reduction of 53 gives 73 as a solid (overall yield 32%). 

Tin forms dihahdes and tetrahahdes with all of the common halogens. These compounds may be prepared by direct combination of the elements, the tetrahalides being favored. Like the halides of tile lower main group 4 elements, all are essentially covalent. Their hydrolysis requires, therefore, an initial step consisting of the coordinative addition of Iwo molecules of water, followed by the loss of one molecule of HX. the process being repeated until the end product ft S111 Oil c is obtained. The most significant commercial tin halides are stannous chloride, stannic chloride, and stannous fluoride. 

Bromomandelic acid has been prepared by the bromination of -bromoacetophenone followed by alkaline hydrolysis 3 by the alkaline hydrolysis of the product formed by the addition of chloral to -bromophenylmagnesium bromide 4 and by the condensation of bromobenzene and ethyl oxomalonate in the presence of stannic chloride followed by hydrolysis and decarboxylation.5 />-Bromomandelic acid is a valuable reagent in the analyses of zirconium and hafnium.6... 

Chloromethylation.1 Chloromethyl methyl ether has been generally used for electrophilic aromatic chloromethylation, but it is highly toxic and now considered a carcinogen. Chloromethylation can be effected by use of a trimethylsilyl ether (1) of a chlorohydrin prepared as shown from trioxane and chlorotrimethylsilane in the presence of stannic chloride in chloroform. This reagent, generated in situ, is effective for chloromethylation of styrene in the presence of SnCl4 any excess is easily decomposed by hydrolysis. Bromomethylation is possible by replacement of ClSi(CH3)3 by BrSi(CH3)3. 

Stannous chloride, the raw material, if it is fresh, is completely soluble in a very little water with much water it hydrolyzes somewhat with precipitation of basic stannous chloride, Sn(OH)Cl. If the stannous chloride is old, it has probably become partially oxidized to stannic chloride, and the latter extensively hydrolyzed to insoluble stannic acid H2Sn03. A clear solution is therefore not obtained when the stannous chloride is treated with a large amount of water. Nevertheless the addition of ammonium sulphide converts all the tin to sulphide, the sulphides being very much less soluble than the products of the hydrolysis. 

Reaction of 1-lithiocyclopropyl phenyl sulphide (123) with 4-t-butylcyclohexanone produces an adduct as a 99 1 mixture of two isomers. By analogy to organometallic addition to this ketone, the stereochemistry is assumed to result from equatorial attack. Treatment of the adduct with one equivalent of anhydrous stannic chloride followed by hydrolysis produces primarily cyclobutanones (equation 94) ... 

Another approach to cephalotaxine intermediate 43 was reported by Weinstein and Craig (65) in 1976 (Scheme 33). The reaction of 3,4-(methy-lenedioxy)-iS-phenethyl tosylate (191), a derivative of the previously used nosylate 117, and sodium 2-carboethoxypyrrole (192), followed by hydrolysis, produced the carboxylic add 193. Intramolecular Friedel-Crafts acylation of 193 with stannic chloride and trifluoroacetic anhydride yielded the benzazepine 194, which was reduced, hydrogenated, and finally oxidized to produce the tricyclic Dolby-Weinreb enamine 43. 

Aluminum bromide, incidentally, shows an interesting type of hydrolysis. With a very little water, such as it absorbs on exposure to moist air, it forms an oxybromide that is insoluble in water, and hydrogen bromide is lost. But if enough water is added at the start, it reacts with considerable evolution of heat to give a clear solution that reacts acid to litmus and probably contains colloidal aluminum hydroxide most of the aluminum, however, is in the form of the very stable hydrated ion Al(OH2)6. The hydrolysis is repressed by the very strong hydration of the cation. A similar hydration occurs when stannic chloride dissolves in water (Experiment 19). 

Fused Azepines.—Formation. A convenient route to benzazepinones (25) in which the aryl ring has an electron-donating substituent (R) is provided by the cyclization of y-(aryl)propyl isocyanates, using phosphorus oxychloride and stannic chloride.The benzazepine-l,3-dione (27) was synthesized by ring-closure of (26) and hydrolysis of the chloroimide (28) that was formed irradiation of (27) produced mainly dimers at the alkene bond. ... 

Tin(IV) chloride is a colorless liquid that fumes in moist air and becomes turbid as a result of hydrolysis. SnCU is very soluble in methanol and miscible with most organic solvents. Goggles and protective clothing should be used when handling stannic chloride since prolonged contact with the skin can cause bums. 

Preparation by hydrolysis of the corresponding propionic ester (SM) with sodium hydroxide in refluxing methanol for 1 h (quantitative yield) [7143]. SM was obtained by acylation of 4-methoxyphenyl propionate with propionyl chloride in nitromethane in the presence of stannic chloride at 20° for 48 h (56%). 

Nitriles may be converted to their imino chloride salts by the action of dry hydrogen chloride in ether. These intermediates ate reduced by anhydrous stannous chloride to stannic aldimonium chlorides, which on hydrolysis yield aldehydes. Chloroform may be added to facilitate the solution of the nitrile. The quality of the stannous chloride catalyst is important the preparation of an active and dependable form has been described. The yields are usually high for many aromatic nitriles, as in the preparation of /3-naphthaldehyde (95%). The reaction has also been employed in the heterocyclic series, as in the synthesis of 4-methyl-thiazole-5-aldehyde (40%). The reduction of the cyano group in the... 

A novel reduction was discovered by Baumstark,126 involving the reaction of dioxetane lb with stannous chloride, leading to pinacol and stannic ion on hydrolysis [Eq. (52)]. Formally it could be considered as... 

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