Synthesis of Lactams by Regioselective Reduction of Cyclic Dicarboximides

Investigation of the Thionation Reaction of Cyclic Imides

“…2,4-bis(4-m ethoxyphenyl)-l,3-dithia-2,4-diphosphetane-2,4-disulfide [1,2,7,8 ]. T here has been som e speculation about the m echanism of the reaction of L R with carbonyl com pounds [7], The m ost probable m echanism is shown in Schem e 1.…”

“…The products w ere identified by F T IR , N M R and elem en tal analysis similarly as described p re viously [1,2,9]. The spectral d ata are given in Table 2.…”

“…This in our opinion explains, why in the case of 5 both m onoand dithioderivatives are obtained. A sim ilar ef fect was observed for a -su b stitu te d aliphatic im ides [2]. D u e to steric constrains the thionation of Thionation procedure: A m ixture of im ide ( 1 -11) (5 m m ol) and L aw esson's reagent (1.51 g, 5 m m ol) in dry toluene (10 ml) was refluxed for 1 h. T hen toluene was evaporated.…”

“…This prom p ted us to synthesise a series of m onothio-and dithioim ides which show in teresting therm otropic p ro p erties and o pen th e access to a new class of liquid crystals [1], It has been reco g nized th at m onothioim ides can be easily desulfurized with R aney nickel to give th e corresponding lactam s [2]. Photochem ical reactio n s b etw een thioim ides and alkenes involve selective cycloaddition to the C=S b ond and yield spiro-adducts [3,4].…”

Applications of Lawesson′s Reagent in Organic and Organometallic Syntheses

“…The preparation of pyridine-2(1H)-thiones was described by Soto et al 141 Scheme 39 Preparation of a thioimide 99 142…”