Stannous chloride dihydrate

A cousin to this reduction is one using stannous chloride (a.k.a. SnCb, a.k.a. Tin chloride) which is done exactly as the calcium one except that about lOOg of SnCb is used in place of the Mg or Ca and the addition occurs at room temperature and the solution is stirred for one hour rather than 15 minutes. Some very good reductions that operate almost exclusively at room temperature with no pressure and give almost 100% yields are to follow. The only reason Strike did not detail these methods is that some of the chemicals involved are a little less common than Strike is used to but all are available to the public. These alternatives include acetlylacetone and triethylamine [73], propanedithlol and trieth-ylamine [74], triphenylphosphine [75], NaBH4 with phase transfer catalyst [76], H2S and pyridine [77], and palladium hydrox-ide/carbon with hydrazine [78], stannous chloride dihydrate [85]. 

Stannous Chloride. Stannous chloride is available in two forms anhydrous stannous chloride, SnCl2, and stannous chloride dihydrate [10025-69-1], SnCl2 2H20, also called tin crystals or tin salts. These forms are sometimes used interchangeably however, where stabiUty, concentration, and adaptabihty are important, anhydrous stannous chloride is preferred. Even after long storage, changes in the stannous tin content of anhydrous stannous chloride are extremely low. Physical properties of the tin chlorides are Hsted in Table 1. 

Stannous Chloride Dihydrate. A white crystalline soHd, stannous chloride dihydrate is prepared either by treatment of granulated tin with hydrochloric acid followed by evaporation and crystallisation or by reduction of a stannic chloride solution with a cathode or tin metal followed by crystallisation. It is soluble in methanol, ethyl acetate, glacial acetic acid, sodium hydroxide solution, and dilute or concentrated hydrochloric acid. It is soluble in less than its own weight of water, but with much water it forms an insoluble basic salt. 

Hydrochloric acid, 37%, Merck, code 317, or equivalent Stannous chloride dihydrate, Merck, code 7815, or equivalent Cupric acetate monohydrate, Merck, code 2711, or equivalent Lead acetate trihydrate, Merck, code 7372, or equivalent... 

The success of this type of reaction depends on the quality of the catalyst. The most active and dependable form of anhydrous stannous chloride 1 is prepared as follows In a 600-cc. beaker is placed 204 g. (189 cc., 2 moles) of acetic anhydride (99-100 per cent) and, while the liquid is stirred by hand, 226 g. (1 mole) of commercial c.p. crystalline stannous chloride dihydrate is added. This operation should be performed in a hood, for the heat of the reaction is sufficient to cause the acetic anhydride to boil. After about one and a half hours, the anhydrous stannous chloride is filtered on a large Buchner funnel, rinsed with two 50-cc. portions of dry ether, and dried overnight in a vacuum desiccator. The yield is quantitative (189 g.). The product may be kept in a tightly closed bottle until it is wanted. The product secured by dehydrating crystalline stannous chloride in an oil bath at 195-200° is satisfactory in many instances but is not dependable. 

Stannous chloride, anhydrous, 23,64 Stannous chloride dihydrate, 22, 32 23, 63... 

A solution of 0.005 mol of a sulfoxide, 2.26g (0.01 mol) of stannous chloride dihydrate, and 2.0 ml of concentrated hydrochloric acid in lOml qf methanol is refluxed for 2-22 hours. The mixture is cooled, diluted with 20 ml of water and extracted with two 25 ml portions of benzene. The dried extracts are evaporated in vacuo leaving virtually pure sulfide which can be purified by filtration of its solution through a short column of alumina and vacuum distillation or sublimation. Yields are 62-93%. 

Dehydrogenation of 6-amino-2,3-dihydrobenzo[6]thiophene-l,l-dioxide with stannous chloride dihydrate is reported to afford 6-aminobenzo[6]thiophene-1,1-dioxide.475 It is noteworthy that 2-methyl-2,3-dihydrobenzo[6]thiophene-l,1-dioxide undergoes ring opening with potassium fer -butoxide to give a quantitative yield of 2-propenylbenzenesulfinic acid.279... 

Stannous chloride dihydrate 4-Chloro-3,5-dinitrobenzonitrile Ethyloxalyl chloride Concentrated hydrochloric acid... 

To a solution of 1.56 mole of stannous chloride dihydrate in 860 ml of concentrated hydrochloric acid is added 0.2195 mole of 4-chloro-3,5-dinitrobenzonitrile. The mixture is stirred at room temperature for 2 hours and cooled to 0°C in an ice-salt bath. A cold solution of 50% sodium hydroxide is added to the mixture until strongly basic. During the addition the temperature is kept below 30°C.The precipitate is removed by filtration and extracted three times with 400 ml of ethyl acetate. The extracts are combined and added to the aqueous filtrate. The phases are shaken well for ten minutes and separated. The organic phase is evaporated to dryness in vacuo. The solid residue is recrystallized from ethanol-water. There is obtained 25.0 g (68%) of 4-chloro-3,5-diaminobenzonitrile, melting point 169-170°C. 

Methylpiperidine Stannous chloride dihydrate 2-Ethoxybenzoyl chloride 4-Dimethylaminopyridine Triethylamine Hydrogen peroxide Chlorosulfonic acid 5-carboxylic acid ethyl ester... 

Stannous Chloride Solution Dissolve 40 g of stannous chloride dihydrate (SnCl2-2H20) in 100 mL of hydrochloric acid. Store the solution in glass containers and use within 3 months. 

To a solution of 300 g. of stannous chloride dihydrate in 300 cc. of concentrated hydrochloric acid (sp. gr. 1.19) in a 1-1. beaker there is added 96 g. of the sulfone, and the mixture is stirred occasionally. Evolution of heat is sufficiently great so... 

Stannous Chloride Reagent (40%). Dissolve 40 g of stannous chloride dihydrate in sufficient hydrochloric acid to produce 100 ml. 

Reagents. Stannous Chloride Solution. A 5% solution of stannous chloride dihydrate in a 25% solution of hydrochloric acid. 

One hundred grams (0.44 mole) of stannous chloride dihydrate is added to a boiling solution of 10 g. (0.0S8 mole) of tetrahydroxy-quinone in 200 ml. of 2.4iV hydrochloric add contained in a 1.5-1. beaker. The initial deep-red color disappears, and grayish crystals of hexahydro-xybenzene precipitate. Two hundred fifty milliliters of 12iV hydrochloric acid is added, and the mixture is heated... 

A solution of 990 g. (4.40 moles) of stannous chloride dihydrate in 975 ml. of concentrated hydrochloric acid is added to 165 g. (0.598 mole) of di-(p-nitrophenyl) sulfide [Org. Syntheses, 28, 82 (1948)]. To initiate reaction, the mixture is warmed on the steam bath to 65°. The reaction mixture is heated to 80-90° for 5 hours and then poured into an ice-cold solution of 1290 g. of sodium hydroxide dissolved in 3230 ml. of water. The precipitated solid is removed by filtration and... 

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