5- isothiouronium bromide

Aminoethyl)isothiouronium bromide hydrobromide [56-10-0] M 281.0, m 194-195". Crystd from absolute EtOH/ethyl acetate. It is hygroscopic. 

The 2-mercapto group was introduced following a two step method [127] of formation and alkaline cleavage of the corresponding iso-thiouronium bromides. Both S-[2//-l,4-benzoxazin-3(4i7)-on-2-yl]-isothiouronium bromide and S-[2/f-l,4-benzothiazin-3(4/7)-on-2-yl]-isothiouronium bromide were obtained. 

Octahydro- (we have used this nomenclature throughout) or perhydrobenzo[c]thiophene (35) exists as the cis and trans isomers and is more commonly named 2-thiahydrindane or 8-thiabicyclo-[4.3.0]nonane. Each stereoisomer may be prepared by treating the corresponding isomer of l,2-di(bromomethyl)cyclohexane with sodium sulfide (details of the products are given in Table IV).45 Cyclization of the cis isomer may be effected partially with thiourea via the formation of cis-hexahydro-o-xylylenebis(isothiouronium bromide) with sodium disulfide it gives a mixture of cis-octahydro-benzo[c]thiophene and cis-2,3-dithiadecalin.46 Optically pure ( —)-(8 R,9I )-lran -octahydrobenzo[c]thiophene has been prepared from (+ )-dicarboxylic acid via reduction of the diacid to the diol, tosylation, and ring closure of the bistosylate with sodium sulfide.47... 

Better yields are obtained from (3-chloropropyl)isothiouronium bromide starting with l-bromo-3-chloropropane. The latter is available by addition of hydrogen bromide to allyl chloride ... 

S-(2-Aminoethyl)isothiouronium bromide bydrobromide [56-10-0] M 281.0, m 194-195 . Crystallise the salt from absolute EtOH/ethyl acetate or MeOH. Store dry as it is hygroscopic in a humid atmosphere. It is a radioprotective agent. When refluxed in EtOH for 16 hours or H2O for 30 minutes, it decomposes to 2-amino-4(5H)-thiazoline hydrobromide which on reciystallisation from isoPrOH/EtOAc has m 175-176 [Doherty et al. 

The effect of Cu(II) ions on ring transformation of S-(2-oxotetrahydrofuran-3-yl)-A-(4-methoxyphenyl)isothiouronium bromide into 5-(2-hydroxyethyl)-2-[(4-methoxyphenyl)imino]-l,3-thiazolidin-4-one has been studied. " ... 

A suspension of S-[ -(phthalimidooxy) ethyl] isothiouronium bromide in acetic acid and 48%-HBr refluxed 3-5 min. until dissolved S-[y -aminooxy) ethyl]-... 

Aq. Na-pyrosulfite and K-carbonate added to a stirred soln. of 500 mg. 2,3,4-tri-0-benzoyl-) -D-ribofuranosyl isothiouronium bromide in methanol containing methyl iodide, the crude product isolated after 3 hrs. at room temp., redissolved in methanol, 0.1 N Na-methoxide added, and allowed to stand 15 hrs. at room temp. 92 mg. methyl l-deoxy-l-mercapto- -D-ribopyranoside. F. e., also prepn. 

The sulfur atom of the thiocarbonyl group is a good nucleophile, and reaction between benzyl bromide and l-(2-thiazolyl)thiourea yields the isothiouronium salt (496). The sulfur atom may also be engaged in a chelate, as exemplified by the Cu chelate of 2-thioureido-4-methylthiazole (491). These chelates with metal ions were thoroughly studied in acidic, neutral, and alkaline media for 66 metal ions in order to define their analytical use. They are formed in the molar ratio of 1 2 for metal II compounds (498). 

Aminopropanols, when reacted with cyanogen bromide, also afford 2-amino-(or imino)-dihydro-1,3-oxazines (Scheme 90) (64ZOB3427), and related thiazines are formed when allylic isothiouronium salts (207) are cyclized with trifluoroacetic acid and stannic chloride. The necessary starting materials are synthesized from aldehydes or ketones by the action of vinylmagnesium chloride and subsequent treatment of the product allyl alcohols (206) first with hydrogen chloride and then with a thiourea (Scheme 91) (77JHC717). 

Place a mixture of 0.5 g of finely powdered thiourea (CAUTION), 0.5 g of the alkyl halide and 5 ml of ethanol in a test tube or small flask equipped with a reflux condenser. Reflux the mixture for a period depending upon the nature of the halide primary alkyl bromides and iodides, 10-20 minutes (according to the molecular weight) secondary alkyl bromides or iodides, 2-3 hours alkyl chlorides, 3-5 hours polymethylene dibromides or di-iodides, 20-50 minutes. Then add 0.5 g of picric acid, boil until a clear solution is obtained and cool. If no precipitate is obtained, add a few drops of water. Recrystallise the resulting S-alkyl isothiouronium picrate from ethanol. 

The analysis of isothiouronium salts, which are conveniently formed by reacting alkyl halides with thiourea, provide a way to study alkyl halides . The H NMR spectrum of s-butylisothiouronium chloride and bromide exhibited enantiomeric discrimination in the presence of [Eu(tfc)3(fod)] The enantiomeric purity of several alkyl methyl phenyl sulfonium ions (73) under conditions of slow inversion was determined using either [Eu(tfc)3(fod)] or [Eu(tfc)4] It was possible to study the inversion barrier by variable-temperature studies in the presence of the shift reagent. 

An iodine-KI-soln. added to a soln. of startg. pyrrole and thiourea in aq. ethanol isothiouronium iodide. Y 85-95%. F. e., also bromides with bromine, s. R. L. N. Harris, Tetrah. Let. 1968, 4045. 

Ethyl bromide refluxed 6 hrs. with thiourea and ethanol, the resulting soln. coned, in vacuo on a water bath, water and aq. NaOH or KOH added during 10 min. to the resulting isothiouronium salt, refluxed 1 hr., cooled, ethyl bromide added dropwise during 0.5 hr., and gently refluxed for 5 hrs. diethyl sulfide. Y 65%. F. e. s. G. Drefahl and H. Schick, Z. Chem. 4, 347 (1964). 

The reaction of halides and subsequent alkaline hydrolysis without isolation of the intermediate isothiouronium salt has been used for the synthesis of thiols. aa -Dimercapto-o-xylene has been obtained from the corresponding bromide in 97% yield. ... 

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