1,3,2,4-Dithiadiphosphetane, 2,4,-bis

Related Reagents. 1,3,2,4-Dithiadiphosphetane, 2,4-Bis-(methylthio)-2,4-disulfide (Davy-reagent methyl) 1,3,2, 4-dithiadiphosphetane, 2,4-Bis(ethylthio)-2,4-disulfide (Davy-reagent ethyl) 1,3,2,4-Dithiadiphosphetane, 2,4-Bis(phenyl-thio)-2,4-disulfide 1,3,2,4-Dithiadiphosphetane, 2,4-Bis-[(4-methox3q)henyl)thio]-2,4-disulfide 1,3,2,4-Dithiadiphosphetane, 2,4-bis(4-methoxyphenyl)-2,4-disulfide (Lawesson Reagent). 

Before going on to consider some of the very valuable reactions of anhydrosulphides, both in the general context of organophosphorus chemistry and also from the viewpoint of more conventional organic synthesis, it is worth considering them briefly from the structural point of view. The so-called thionophosphine disulphides are (generally) dimeric and possess the 1,3,2,4-dithiadiphosphetane 2,4-disulphide structure. As normally prepared, the compounds exist in the trans form 207, as evidenced by X-ray analyses of, for example the 2,4-dimethyl , 2,4-diphenvl (powder structure) 2,4-bis(4-methoxyphenyl) and 2,4-bis(2,4,6-triisopropylphenyl) compounds. Evidence has been obtained which clearly demonstrates the ability of the cyclic structure to dissociate and re-form under varied con-... 

THIATION WITH 2.4-BIS(4-NETHOXYPHENYL)-1.3.2.4-DITHIADIPHOSPHETANE 2.4-01SULFIDE N-ICTHYLTHlOPYRROLIDONE... 

I-Thiono-1,3-dihydrobenzo-2-tellurophenc1 In a 250 ml flask fitted with a reflux condenser are placed 1.50 g (1.6 mmol) of tellurophthalide, 1.35 g (3.3 mmol) of 2,4-bis 4 -methoxyphenyl]-2,4-dithioxo-l,3,2,4-dithiadiphosphetane (Lawesson s reagent), and 100 ml of benzene. The mixture is heated under reflux for 2 h, the resultant dark green solution is evaporated, the residue is dissolved in dichloromethane, the solution is filtered through a column of silica gel, and the filtrate is evaporated. The residue is recrystallized from hexane yield 0.9 g (62%) m.p. 98°. 

Cyclopropyl ketones and lactams as well as amides of cyclopropanecarboxylic acids were converted to the corresponding thiocarbonyl compounds on reaction with 2,4-bis(4-methoxyphenyl)-l,3,2,4-dithiadiphosphetane-2,4-dithione (Lawesson s reagent) in benzene or toluene the yields were good. For example, reaction of lactam 1 to give thione 2. Thiones were also formed when hydrazones were treated with sulfur monochloride. ... 

A diversity of thiolactams has been prepared from the corresponding lactams by use of LR or of the modified reagent (13). Monobactam analogs, e.g., the weakly antibacterial -thiolactam (93), have been prepared by thionation of suitably protected optically active /3-lactams with LR or Davy s reagent (2,4-bis (methylthio)-l,3,2,4-dithiadiphosphetane disulfide), deprotection and subsequent introduction of the side chain. Very recently, an efficient solid-phase synthesis of 1,3,4-trisubstituted /3-thiolactams has been described. The y-thiolactam (94) has been prepared as an intermediate for the synthesis of analogs of the acetylcholinesterase inhibitor huperzine B. Transformation of the quinoline alkaloid cytisine into its thio analog (95) enhanced its biological activity. ... 

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