Stannic acid chloride

The reaction was carried out in excess of the acid chloride with cooling and gave yields of 55-80%. Of the catalysts tested, stannic chloride gave the best results. ... 

In 1888, Turpin prepd a series of cool expls which were permissable, by incorporating materials such as alkali chlorides, Na or K bicarbonate (up to 50% content), fluorides, acetates, oxalates, Ba carbonate. 10H2O, chromates, hyposulfites, stannic acid, boric acid, borates, etc, in the expls listed above eg, a) K chiorate 45, double salt of Ca and K acetochlorate 35, tar 18, charcoal 5, and alkali bicarbonate or oxalate I5ps b) K chlorate 15, double salt of K and Amm chlorobichromate 35 K or Na nitrate 10, tar 18, charcoal 5, and K or Na bicarbonate 15ps... 

Sn = 4H this must be borne in mind when calculating the quantities required for the reaction. The stannic chloride forms the complex chloro-stannic acid with hydrochloric acid, which combines with the aniline produced in the reaction ... 

Reaction of alkenyl silanes with acid chlorides is catalyzed by aluminum chloride or stannic chloride.126... 

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%). 

Two years later, Craig and Robinson attempted an alternative synthesis of 8 with a more symmetrical pathway starting from derivatives of fluoranthene. Cycliza-tion of fluoranthene-7,10-diacetic acid 14 was attempted to produce diketone 15, expected to enolize to the dihydroxycorannulene 16. Unfortunately, several attempts at cyclization failed, including anhydrous hydrofluoric acid, concentrated sulfuric acid, and polyphosphoric acid. Friedel-Crafts cyclization of the corresponding acid chloride of 14 with aluminum or stannic chloride was similarly unsuccessful. However, although Craig and Robinson were not successful, they developed a convenient synthesis of 7,10-disubstituted fluoranthenes which turned out later to be of premium importance in a new, successful synthesis of corannulene. 

Tin(II) and Tm(IV) Hydroxides. Prepare tin (I I) and tin(IV) hydroxides in separate test tubes from solutions of tin chlorides. What reagent should be used to precipitate the tin hydroxides Do tin hydroxides exhibit amphoteric properties What tin compounds are known as a- and P-stannic acids How are they prepared Write the equations of the reactions. 

Preparation of a-Stannic Acid. Add a 10% ammonia solution to a tin(IV) chloride one up to complete precipitation. Wash the product with water by decantation until the chloride ions are removed and filter it off on a Buchner funnel. Test the reaction of a-stannic acid with water, acids, and alkalies. Do the properties of this acid remain the same after prolonged standing or boiling Perform the relevant experiments. 

A soft, almost silver-white metal, melting at 231° C. Tin dissolves in hot hydrochloric acid with the formation of stannous chloride. Hot concentrated nitric acid converts it into insoluble meta-stannic acid. 

With Thionyl Chloride. Although thionyl chloride has been more widely used in the preparation of acid chlorides for cyclization with both stannic and aluminum chloride, it is perhaps less generally advantageous than phosphorus pentachloride. If it is desired to obtain the acid chloride essentially free of by-products, thionyl chloride presents some advantage in that these by-products of the reaction are gaseous and therefore may be eliminated readily. Since, moreover, the reagent has a... 

In spite of the many disadvantages, thionyl chloride has been used with considerable success in numerous cyclizations. A generally effective procedure for preparing the acid chloride involves the treatment of a dry ethereal solution of the acid with an excess of thionyl chloride and a drop or two of pyridine as a catalyst.90 By this method, in conjunction with stannic chloride and benzene for the cyclization, excellent yields of ketones (Table VI, examples without asterisks) were obtained. The ring closure of 7-l-naphthylbutyric acid affords a typical illustration of the procedure. 

A list of ketones which have been prepared by the Friedel-Crafts stannic chloride method may be found in Table VI. Yields marked by an asterisk were obtained from acid chlorides prepared by the phosphorus pentachloride procedure all others were obtained from acid chlorides prepared from thionyl chloride. 

Stannic Chloride pn the Free Acid. Ring closure by heating the free acid with stannic chloride at 100-120° has been shown to be successful on several types of acids.85 47> 8 88 80, 189 819 These and some other acids which have been cyclized by this method may be found in Table XI. In four instances (items 3, 7, 14, 17) stannic chloride treatment gave better results than sulfuric acid. Eleven of the acids in Table XI (items 3, 5, 8, 9, 10,12, 13, 14, 16, 17, 18) have been cyclized also by the Friedel-Crafts method on the acid chloride. With seven acids (3, 6, 8, 9, 12, 14, 17) the yields were better, while with four (5, 10, 16, 18) they were lower, than with stannic chloride. Except for one (18) of these latter acids, however, there seems to be some question as to whether the optimum conditions for the Friedel-Crafts reaction were employed. Of the acids (4, 6,12) which have since been cyclized with hydrogen fluoride, considerable improvement in yields was realized. 

Miscellaneous Ferroceno Heterocyclic Compounds Treatment of the acid chloride of S-ferrocenylmethylthioglyeolic acid with stannic chloride in methylene chloride at —70° gave l,2-(2-thia-4-oxotetramethylene)ferrocene (27).17 Reaction of 27 with Raney nickel led to ring opening and gave a mixture of l-methyl-2-ethyl-... 

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. 

For example, reaction of cyclohexenecarboxylic acid chloride (1) in CH2CI2 with trimethylvinylsilane in the presence of stannic chloride at —30° and finally at 20° leads to the bicyclic enone 2 in 46% yield. The reaction involves an intermediate dienone (a) that cyclizes under acidic conditions (Nazarov reaction). Although yields are not high, this one step synthesis of bicyclo[h.3.0]enones is very convenient. ... 

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