Dithiourethans

For the synthesis of 2-alkylthio-TA 36, several methods based on the cyclization of dithiourethanes (33, 34, and 35) are suggested (66TL3225 70AJC51 82CCC3268). Compounds 34 are intermediates, but dithiourethanes 33 and 35 were first isolated, then introduced into the cyclization reaction (Scheme 7). 

For the xanthate method see page 654. In the aliphatic series dithiols269 and unsaturated thiols270 are best prepared by Braun s dithiourethane method. 

A quadrant rule (Fig. 3) for the n-71 Cotton effect of the N-dithiocar-bomethoxy (dithiourethane) chromophore R—S—CS—has been proposed (Ripperger and Schreiber, 1965 Ripperger, 1967, 1969). According to the experimental results, the signs are as shown in Fig. 4. It has been stated that this quadrant rule can be applied to pyrrolidines and open-chain compounds. 

Amide mercaptals Dithiocarbamic acid esters Dithiourethans Iminodisulfides Iminodithiocarbonic acid esters... 

Dithiocarbamic acid aryl esters 43,485 ---esters (s.a. Dithiourethans)... 

Mercuric oxide s. under BFg Zinc chloride (s. a. under RgSiH) 4-Thiazoline-2-thiones from dithiourethans... 

Thiazoline-2-thiones from isothiocyanates via dithiourethans—4-Thiazolin-2-ones from isocyanates via thiourethans s. 17, 648 dithiourethans cf. E. Gherbuliez et al., Helv. 48, 1414 (1965)... 

Phenyl isothiocyanate and anhydrous K-carbonate in benzene ice-salt-cooled and treated with 2-mercapto-3-pentanone, more benzene added, and heated to reflux N-phenyl-S-(3-oxo-2-pentyl) dithiourethan (Y 87%) refluxed 3 hrs. with anhydrous ZnGl2 in abs. methanol 3-phenyl-4-ethyl-5-methyl-4-thiazo-line-2-thione (Y 90%). F. e., also 4-thiazolin-2-ones from isocyanates via thio-uretbans and without isolation of the intermediates (cf. Synth. Meth. lA, 655), s. K. Riihlmann, A. GrosaJski, and U. Schrapler, J. pr. 11, 54 (1960). 

The isothiocyanates can react further, e. g., with hydroxy compounds or thiols, to form thio-urethanes or dithiourethanes. In the presence of amines, thioureas result while hydrolysis yields the corresponding amines and releases CO2 and H2S ... 

Ci6Hi7N02S2, S-(2-Methoxyphenyl)-N-(2,6-dimethylphenyl)dithiourethane sulfenic acid, 38B, 97... 

Whereas aminolysis of primary and secondary alkyl xanthate esters gives thioneurethanes, dithiourethanes are formed, equally exclusively, when tertiary alkyl xanthates are employed, the relief of steric hindrance on... 

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