O-thiocarbamate

In the reaction of 1-chlorothioformimidinium chlorides with phenols a mixture of thiocarbamic O-esters XXXIV and alkyl halides is obtained (" I. 

In 1999, it was reported that the palladium catalyzed azathiolatiori, that is, the addition of the S-N bond of sulfenamide 115 to carbon monoxide can be catalyzed by palladium(O) complexes in pyridine to provide the thiocarbamate 116 in good yields (Eq. 7.69) [67]. Contrary to the other S-X bond activations described so far, where X has the same electronegativity as S (i.e. X = S) or lower (X = H, B, Si, Ge, and P), the S-N bond has a strong S -N bond character and shows unique reactivity. 

Thiocarbamate (tc, RHNCSO-) is a monodentate ambidentate ligand, and both oxygen- and sulfur-bonded forms are known for the simple pentaamminecobalt(III) complexes. These undergo redox reactions with chromium(II) ion in water via attack at the remote O or S atom of the S- and O-bound isomers respectively, with a structural trans effect suggested to direct the facile electron transfer in the former.1045 A cobalt-promoted synthesis utilizing the residual nucleophilicity of the coordinated hydroxide in [Co(NH3)5(OH)]2+ in reaction with MeNCS in (MeO)3PO solvent leads to the O-bonded monothiocarbamate, which isomerizes by an intramolecular mechanism to the S-bound isomer in water.1046... 

Ruzo, L.O. and Casida, J.E. Photochemistry of thiocarbamate herbicides oxidative and free radical processes of thiobencarb and diallate, J. Agric. Food Chem., 33(2) 272-276, 1985. 

While the cyclohexenyl and cycloheptenyl derivatives roc-14aa-14ag and rac-14ba were stable at room temperature, the cyclopentenyl O-allylic thiocarbamates already suffered a partial rearrangement at ambient temperatures [19, 20] while the acyclic O-allylic thiocarbamates showed an intermediate thermal stability. 

Table 2.1.4.12 Pd(0)/BPA-catalyzed rearrangement of racemic acyclic O-allylic thiocarbamates.

The sense and degree of asymmetric induction of the Pd(0)-catalyzed rearrangement of the cyclic and acyclic O-allylic thiocarbamates in the presence of BPA are the same as, or similar to, those in the Pd-catalyzed substitutions of the corresponding cyclic and acyclic racemic allylic carbonates and acetates with sulfinates and thiols. It is therefore proposed that Pd(0)/BPA reacts with the racemic O-allylic thiocarbamate with formation of a jt-allyl-Pd(II) complex, which contains as counter ion the corresponding thiocarbamate ion (Scheme 2.1.4.19) [23, 24]. Substitution of the jt-allyl-Pd(II) complex by the thiocarbamate ion gives the S-allylic thiocarbamate and the Pd catalyst. 

The Pd-catalyzed allylic alkylation of sulfinate ions, thiols, and thiocarboxylate ions with racemic cyclic and acyclic allylic esters in the presence of bisphosphane BPA generally provides for an efficient asymmetric synthesis of allylic sulfones, sulfides, and thioesters. The Pd-catalyzed rearrangements of allylic sulfinates and allylic O-thiocarbamates, both of which proceed very efficiently in the presence of BPA, are attractive alternative ways to the asymmetric synthesis of allylic sulfones and allyUc thioesters also starting from the corresponding racemic alcohols. 

Uses. There may be some captive use of carbonyl sulfide for production of certain thiocarbamate herbicides (qv). One patent (38) describes the reaction of diethylamine with carbonyl sulfide to form a thiocarbamate salt which is then alkylated with 4-chlorobenzyl halide to produce 5- (4- chi o r o b enzyl) A/, A/-diethyl thiocarbamate [28249-77-6], ie, benthiocarb [28249-77-6]. Carbonyl sulfide is also reported to be useful for the preparation of aliphatic polyureas. In these preparations, potassium thiocyanate and sulfuric acid are used to first generate carbonyl sulfide, COS, which then reacts with a diamine ... 

The two pyrimidine rings of 1,2,3,4-tetrahydro-6//-pyrimido[2,1-b]-quinazolin-6-one (517) were simultaneously formed when ethyl Ar-(2-methoxy-carbonylphenyl)thiocarbamate was cyclized with 1,3-diaminopropane (82JHC1117). The two heterocyclic rings of 1,2,3,4,5,6-hexahydropyrimido[2,l-6]quinazolin-2-ones (519) were also concomitantly formed when compounds 518 were cyclized with cyanogen bromide [73GEP(O)2305575 76USP3932407]. 

A low-temperature study in superacid media of mono-, di-, and tri-protonated thiourea has been carried out.302 The experimental results were confirmed by theoretical calculations. Monoprotonation occurs at sulfur and, whereas the mono- and di-protonated forms are thermodynamically stable, the triprotonated ion is only kinetically stable. The pyrolysis of A-acctylthiourea and /V,/V -diacctylthiourea (335) are unimolecular first-order eliminations.83 Acid-catalysed ethanolysis of N,N -di- and tri-substituted aryl- and alkylaryl-thioureas gives O-ethyl /V-aryl thiocarbamates and amines.303 The acid-catalysed hydrolysis of thiourea was first order in thiourea and acid.304... 

It has been reported <1998CC2315> that a similar [2+2] intramolecular cyclization of (2-cyclohex-l-enyl-2-methyl-propionyl)phenyl-thiocarbamic acid O-methyl ester leads to the formation of tricyclic thietane in 85% yield (Table 2). 

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