2-5-ethyl-2-thio hydrolysis

Treatment of ethyl rhercaptan with thiocyanogen affords ethyl thio-thiocyanate (50% yield)a compound similar to a sulfenyl chloride (RSCl) but somewhat more stable toward hydrolysis. Thiophenols... 

In the previous paragraph we have noted two different systems in which metal-ion catalysis of co-ordinated ester hydrolysis has respectively a lower and a higher activation enthalpy than that for hydrolysis of the free ester. In the case of metal-ion-catalysed hydrolysis of ethyl thio-oxalate ( 02CC0SEt) it is noteworthy that whereas hydrolysis in the presence of lead(n) has a higher activation enthalpy than hydrolysis of the free ester, hydrolysis in the presence of magnesium(n) has a lower activation enthalpy (Table I). ... 

Alkylation of ll-mercaptopyrido[l,2-h]cinnolin-6-ium hydroxide inner salts (e.g., 41) with ethyl bromoacetate gave ll-(ethoxycarbonylmethyl(thio derivatives 64 (R = H), which could be hydrolyzed to the ll-(carboxy-methyl)thio derivative or back to the starting compound 41 (74JHC125). Hydrolysis of the ll-bis(methoxycarbonyl)methylene 66 (R = H), and 2-cyano derivatives of 17 (R = H) in boiling HCl afforded 11-methyl and 2-carboxylic acid derivatives, respectively (74JHC125). The 2-nitro derivative of 17 (R = H) was reduced to the 2-amino derivative over Pd/C with NaBH4 in aqueous methanol, and the 2-amino group was acylated with acetic anhydride at 100°C. 

It is possible to degrade 2-amino-2-deoxyhexoses to 2-amino-2-deoxy-pentoses by means of chain-shortening reactions from the nonreducing end of the molecule. Thus, Wolfrom and Anno38 converted ethyl 2-acetamido-2-deoxy-1 -thio-a-d-glucofuranoside (XV) into 2-amino-2-deoxy-a-D-xylose hydrochloride (XVI) by sequential application of periodate oxidation, borohydride reduction, and hydrolysis, as in the following reaction scheme. 

Wolfrom and coworkers had found that the mercaptolysis of the crystalline calcium chloride double salt of streptomycin trihydrochloride yielded, after chromatographic purification, two anomeric forms of ethyl tetraacetylthiostreptobiosaminide diethyl mercaptal. Mercaptolysis of dihydrostreptomycin yielded an amorphous ethyl dihydrothio-streptobiosaminide hydrochloride which formed crystalline N-acetyl and pentaacetyl derivatives. The ability of the ring in this latter compound to resist hydrolysis and to form a thioglycoside instead of a thio-... 

Thiophenealdehyde has been prepared by the decarboxylation of 2-thienylglyoxalic acid, by the action of 2-thienylmagne-sium iodide on ethyl orthoformate followed by hydrolysis of tbe acetal, in small yields by the Rosenmund reduction of 2-thio-phenecarboxylic acid chloride, in small yields by the action of hydrogen cyanide, hydrogen chloride, and aluminum chloride on thiophene using benzene as a solvent, by a series of reactions from l-chloro-2,3-diketocyclopentane, by the hydrolysis of 2-thienylmethylhexamethylenetetrammonium chloride in neutral solution, and by the action of N-mcthylformanilidc on thiophene in the presence of phosphorus oxychloride. ... 

Thioaldoses can form hemiacetal seven-membered septanose rings, provided that C-5 and C-4 hydroxyl groups are protected to avoid the fonuation of the more favorable furanose and pyranose rings. Thus, acid hydrolysis of 446 gave 2,3,4,5-tetra-O-methyl-6-thio-D-galactoseptanose (447) and ethanolysis afforded an anomeric mixture of the ethyl thioseptanosides 448. The isomerization to... 

In an investigation of the hydrolysis of ethyl 1-thio-a-n-glucopyranoside, Pacsu and Wilson found that rotational change could not be used to determine the hydrolysis rate-constant, because, in addition to D-glucose, ethyl S-D-glucofuranoside and ethyl a-o-glucopyranoside are formed. 

The hydrolysis of glycose diethyl dithioacetals and 1-thioglycosides in the presence of mercuric chloride represents a special case where the high afl nity of mercury for the sulfur function profoundly influences the reaction. The procedure has been used as an alternative to acid hydrolysis for conversion of a 1-thiofuranoside into the free sugar without cleavage of an acid-labile group, as in the one-step conversion of ethyl 2-acetamido-2-deoxy-l-thio-o-D-xylofuranoside into 2-acetamido-2-deoxy-D-xylose. Attempted replacement of the ethylthio group by methoxyl in ethyl 1-thio-/3-D-mannopyranoside, with mercuric chloride and cadmium carbonate in methanol, was unsuccessful. Mercuric chloride normally effects desulfurization of acyclic dithioacetals. ... 

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