Reaction with Lawesson’s reagent

This ring system was prepared by the alkylation of [ 1,4]benzothiazinone with ethyl bromoacetate followed by reaction with Lawesson s reagent and cyclization with hydrazine to give the thia analogue of 503 (91MI6). 

Another example of conversion of a carbonyl into a thiocarbonyl is provided by dibenzodiazocinone 32 which, upon reaction with Lawesson s reagent, furnished the dithiocarbonyldiazocine 33 in 91% yield <2004JOC1248>. 

A -Acetyltryptophan ethyl ester on reaction with Lawesson s reagent afforded the thioamide 9, which with methyl iodide in acetone yielded the methylthioiminium salt 10 which cyclized spontaneously to the quaternary salt 11 (24). BC 12 on condensation with benzaldehyde gave stilbene 13, which oh oxidation with potassium permanganate afforded... 

Carotenoid and supracarotenoid TTFs became available in a general synthesis involving the dimerization of co-(l,3-dithiol-2-ylidene) polyenals 820 by reaction with Lawesson s reagent. The aldehydes 820 were prepared by reaction of unsaturated dialdehydes 819 with 818 and triphenylphosphine (Scheme 124) <2003HCA2589>. 

Synthesis of ly3-Thiazole-5(4/ ft-thiones. The preferential thionation of /V,/V-disubstituted carboxamides can be used for a convenient synthesis of 2,4,4-trisubstituted l,3-thiazole-5(4/ -thiones of type 11. Treatment of Wacylated a,a-disubstituted a-amino acid amide 10 with 1 in toluene/pyridine at 100 °C gives 11 as the sole product. In contrast, the analogous reaction with Lawesson s reagent leads exclusively to the corresponding 1,3-thiazol-5(4/0-one 12 (eq 5). ... 

A variant involves the use of the a,a -thiobisketones in reaction with Lawesson s reagent which produces 1,4-dithiins, e.g. 43, from which, by expulsion of sulfur, aromatic thiophenes result, as in the example in Scheme 65 [108]. However, expulsion of either dithiin sulfur is possible, so a mixture of isomers results, but usually with one isomer predominating. 

Ph3P=CHC(0)Me].2-Acetamido-l,3,4,6-tetra-0-acetyl-2-deoxy-a-D-glucopyr-anose was converted into the tetrazole derivative 114 by reaction with Lawesson s reagent then trimethylsilyl azide and tin(IV) tetrachloride. 

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