Thiol 1-thiolactam

When a,/3-unsaturated esters are the target molecules, the use of a thioaldehyde or thioketone is advisable for the easy elimination of H2S from the intermediate thiol adduct. This strategy has been applied to thiolactams 94a and to thionolactones 94b, opening a route to vinylogous carbamates 95a143 and carbonates 95b144(equation 57). 

When / -amino thiols and, / -unsaturated esters are used, addition is accompanied by condensation and ring closure to afford seven-membered thiolactams [tetrahydro-1,4-thiazepin-5(2 )-ones] in yields of up to 96% 22... 

Monothioacetals 1,3-Oxathiolanes Thiolactams S extrusion, 59-60, 261 Thiols synthesis from haloalkanes, 169, 269 Thionation of lactones, 110-111 Thiones olefination of, 35 Thionocarbonates. See Carbonothioates Thionolactones, 110-111 Thionyl chloride prepn. of acyl halides, 143 prepn. of carboxylic esters, 347 prepn. of haloalkanes from alcohols, 32 Thiophenoi. See Benzenethiol Thiotosylatc. See Benzenesulfonothioic add... 

The thiolactams can be alkylated on sulfur by treatment with alkyl halides and base under aqueous or nonaqueous conditions, for example, (99 X = S) is converted into (100) (Scheme 16) <82CPBil4l>. The thioether (100) can be obtained directly from the lactam (99, X = O) on reaction with dimethylaminoethane thiol in the presence of either titanium tetracUoride or silicon tetrachloride other Lewis acids were ineffective <82CPB1473>. 

The only thiols forming iodoacetylenic sulphides were heterocyclic thiols having a tautomeric thiolactam structure. 

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