Alkylation sulphamic esters

Relatively few high yielding and convenient procedures are available for the synthesis of sulphamic esters, but the reaction of alcohols with sulphamoyl chlorides under basic conditions in the presence of a phase-transfer catalyst provides a simple route [32]. When the ratio of alcohol to sulphamoyl chloride is increased to 2 l, the A-alkyl sulphamic ester is produced (Scheme 3.11). 

Alkylation of sulphamic esters under phase-transfer catalytic conditions (Table... 

The introduction of the adamantyl group into a sulphamate ester has been achieved by an extension of the reaction in equation 29219. The unsubstituted esters 177a-f were alkylated under solid-liquid (equations 31-34), liquid-liquid (equations 35 and 36) phase transfer catalysis conditions and in a homogeneous medium (equations 37 and 38) by reaction with 1-adamantyl bromomethyl ketone. 

The phase transfer catalysis process has also been extended to synthesize the alkyl and aryl esters (170) of N-aryl sulphamic acids212 (equation 23). If the ratio of aliphatic alcohol (169) to sulphamoyl chloride (168) is increased from 1 1 to 2 1, then N-alkyl-iV-arylsulphamate esters (171) with similar alkyl groups are obtained together with considerable amounts of iV-arylsulphamic acid esters (170). The exclusive formation of the iV-alkyl-iV-arylsulphamate esters (171) can be achieved by employing longer reaction times. A second approach to the synthesis of 171 would be to react the iV-methyl-iV-phenyl sulphamoyl chloride (172) with the alcohol. This was attempted, but the ester failed to form even under forcing conditions. The corresponding AT-alkyl iV-arylsulphamate ion (173) was isolated (equation 24) hydrolysis to the acid was considered to occur as opposed to nucleophilic displacement of the chloride by the methanol. 

Sulphamic acid 1,7-heptanediyl ester 261 is a weak alkylating agent which has exhibited cytotoxicity and has an effective shelf-life (t 90%) of 9.3 days. A mechanistic investigation... 

Sulphamoyl chloride when reacted with hydroperoxides in the presence of pyridine below — 30 °C leads to the formation of the novel alkyl sulphamoyl peroxides H2NS0200CH2R (R = CH2CH3, CH2CH2CH3) 303 (equation 98)305. Hydrolysis or ammonolysis of these compounds leads to formation of sulphamic acid or sulphamide respectively. 2-Nitrophenylsulphamoyl chloride (304), prepared from the corresponding sulphamic acid by reaction with PC15, has been used to prepare iV-(2-nitrophenyl)-iV -substituted sulphamides (305) and aryl esters (306) (equation 99)306. 

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