5- isothiuronium

By hydrolysis of a phthalocyaninc containing an in situ generated alkyl isothiuronium salt, alkyl thiols as side chains have been obtained.438... 

Reaction of alkyl halides with NaSH cleavage of isothiuronium salts... 

Perfluoroalkyl)ethane thiols have been used as precursors to fluorinated surfactants and products for hydro- and oligophobic finishing of substrates such as textiles and leather (1). The synthesis of 2-(perfluoroalkyl)ethane thiol and a byproduct bis-(-2-perfluoroalkylethane)-disulfide (5-10%) has been practiced via the reaction of 2-(perfluoroalkyl)ethane iodide with thiourea to form an isothiuronium salt which is cleaved with alkali or high molecular weight amine as shown in Equation 1 for 2-(perfluorohexyl)ethane iodide (1). 

A critical study of the preparation of the two anomeric 6-desoxy-D-glucose tetraacetates (LXXXIV) from D-glucose has been made by Hardegger and Montavon.70 The final step, namely, the reduction of the two 6-iodo-6-desoxy-D-glucose tetraacetates (LXXXII) in high yield, proved to be particularly difficult and a variety of methods were studied. Highest yields were obtained when LXXXII was allowed to react with thiourea to form the S-substituted isothiuronium iodide (LXXXIII) which was then desulfurized with Raney nickel. In actual practice the 6-iodo derivative was refluxed briefly in amyl alcohol with thiourea and... 

Another type of cyclization reaction with thioureas has been observed by Ueno et Here l,3-thiazetidin-3-ylium salts (179) are obtained in good yields by treatment of chloromethylsulfoxide with substituted thioureas followed by treatment of the resulting isothiuronium chlorides with coned H2SO4 and NaBPh. The methanesullinyl unit acts as the leaving group in this cyclic nucleophilic substitution reaction. 

Concentration of the filtrate to a volume of about 250 ml. and recrystallization from 95% ethanol of the crude isothiuronium salt which separates gives an additional 130 g. of material. The total yield of the salt is 1234 g. (90%). 

An unexpected reaction occurred when an attempt was made to convert 2-chloromethyl-5-methoxypyran-4-one (512) into its isothiuronium salt. Opening of the pyran ring and recyclization to a benzene ring followed by thiazole ring formation accounts for the formation of 2-amino-5-hydroxy-6 methoxybenzothiazole hydrochloride (513) (80JHC817). 

When the reaction is conducted in the presence of at least an equimolar quantity of acid, the isothiuronium salt (IX) may be obtained in yields up to 80%, The nature of the products obtained on... 

Polystyrene-bound isothiuronium chloride, which is readily prepared from chloro-methyl polystyrene and thiourea, has been used as a starting material for the preparation of various substituted pyrimidines (Entries 9-11, Table 15.28). After oxidation to the corresponding sulfones, nucleophilic cleavage with amines proceeds smoothly to yield substituted 2-aminopyrimidine derivatives (see Section 3.8). 

Solid-phase syntheses of triazines (Table 15.32) include the cyclocondensation of polystyrene-bound isothiuronium salts with /V-(cyano)iminodithiocarbonates and the cyclization with simultaneous cleavage from the support of derivatives of a-amino acid hydrazides (Table 15.32). (Benzylthio)triazines, such as those listed in Table 15.32 (Entries 1 and 2), have been cleaved from a support by oxidation to sulfoxides or sul-fones with N-benzenesulfonyl-3-phenyloxaziridine, followed by nucleophilic cleavage with primary or secondary aliphatic amines or with electron-rich anilines (see Section 3.8). 

Thiourea and a-chloropropenoic acid give isothiuronium salts (or their esters) which, when cooled and treated very gradually with aqueous NaOH, lead to the 4-hydroxythiazine 48 or its tautomer 49 (Scheme 29) (51LA140). 

Fig. 8. Recording of t—E curves during the course of a reaction Reaction of S-ben-zyl-isothiuronium chloride with hydroxide and carbonate ions in carbonate buffer pH 9.7. Initial concentration of S-benzylisothiuronium chloride 4 x 10 4M. Anodic waves of benzylmercaptan formed were recorded after intervals given in the polarogram. Curves starting at — 1.0 V towards more positive potentials, S.C. E., 200 mV/absc., h = 70 cm, full scale sensitivity 2.2 p.A...

Thiophosphorsaure-amid-O-ester-(l-imino-alkylamide) werden aus Thiophos-phorsaure-amid-chlorid-O-estern z.B. mit 2-Methyl-4,5-dihydro-imidazol551, S-Alkyl-isothiuronium-Salzen552 bzw. Amidinium-Salzen553 erhalten ... 

The preparation of 97 was optimized later by Misumi et al. by coupling of the thiolate 94 formed in situ, using the thiocyanate 95 or the isothiuronium salt 96 with the tetrabromide 93 [87], The formation of reactive thiolate groups in the course of the reaction maintains a lower concentration of free thiolate anions and thereby restrains side reactions [87]. 

Using the base CsOH in ethanol/benzene (12 1) as the solvent and the isothiuronium salt 96 increased the yield of the isomeric cyclic compounds 97 to 75 %. The... 

In the reaction of 4-methyl-3,4-epoxytetrahydropyran 370 with thiourea in water at 0 °C for 5 h, in the presence of an equimolar amount of sulfuric acid, 3 -(4-hydroxy-4-methyl-3-tetrahydropyranyl)isothiuronium sulfate 371 was formed in 70% yield. Addition of an equimolar amount of sodium carbonate in water to 371 at 0-5 °C for 6h give 4-methyl-3,4-epithiotetrahydropyran 372 in 78% yield (Scheme 104) <2003HC174>. 

Chloroquinoxaline (1) affords quinoxaline-2(l/f)-thione (16) in 73% yield upon treatment with thiourea in methanol, followed by hydrolysis of the intermediate isothiuronium salt with sodium hydroxide. ... 

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