Alkyl thiocyanates, reduction

A variety of solvents was investigated for this reaction, as shown in Table 15.1. As inferred from Table 15.1, the hydrogenolysis performance is best in more polar solvents snch as acetonitrile, acetone, ethyl acetate, and acetic acid. Only in o-dichlorobenzene is the rate of reaction ranch lower than predicted by the dielectric constant. The presence of nonpolar solvents snch as hexane and the thiol product resulted in large amonnts of the disnlfide intermediate. It has been shown that the disnlfide is the intermediate in stoichiometric rednctions such as samarium diiodide reduction of alkyl thiocyanates to thiols (11) so it is reasonable to expect it as the... 

Alkyl thiocyanates (39) are reasonably stable, volatile oils, with a slight garliclike odour. They are readily oxidised to either sulfonyl cyanates (40) or sulfonic acids (41), and by reduction they yield thiols (Scheme 22). 

Titanium(IV) chloride and titanocene dichloride have catalytic effects on the reduction, e.g., in the transformation of alkyl thiocyanates to dialkyl disulfides and nitroarenes to aryl amines, respectively. 

Pyrrolethiols, readily obtained from the corresponding thiocyanates by reduction or treatment with alkali, rapidly oxidize to the corresponding disulfides. They are converted into thioethers by reaction with alkyl halides in the presence of base. Both furan- and thiophene-thiols exist predominantly as such rather than in tautomeric thione forms. 

Silver fluoborate, reaction with ethyl bromide in ether, 46, 114 Silver nitrate, complexing with phenyl-acetylene, 46, 40 Silver oxide, 46, 83 Silver thiocyanate, 45, 71 Sodium amide, in alkylation of ethyl phenylacetate w ith (2-bromo-ethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1 bromobutane to give 2,4-nonanedione, 47, 92 Sodium 2 ammobenzenesulfinate, from reduction of 2 mtrobenzenesul-finic acid, 47, 5... 

Pyrimidinones, 5-methylsulfonyl-synthesis, 3, 138 Pyrimidin-2-ones IR spectra, 3, 64 Pyrimidin-2( 1H)-ones acidic pKa, 3, 60 alkylation, 3, 90 nitration, 3, 69 pKa> 3, 60 reduction, 3, 75 synthesis, 3, 132 Pyrimidin-4(3/7)-ones alkylation, 3, 90 synthesis, 3, 132 thiation, 3, 89 Pyrimidinophanes synthesis, 7, 768, 774 Pyrimidinopurinophanes synthesis, 7, 766 Pyrimidin-2-yl thiocyanate synthesis, 3, 95... 

Aldol condensation of the zinc enolate of resin-bound alkyl ester 29 with aromatic aldehyde or ketone forms a P-hydroxy ester, which upon treatment with DIBAL-H leads to simultaneous reduction and cleavage of the ester moiety from the resin to give a soluble 1,3-diol 31 [31], Parallel synthesis utilizing three ester and nine carbonyl building blocks afforded a library of 27 analogs which was screened for antioxidative efficiency using a ferric thiocyanate assay. 

The ability of phosphines to act as both a metal oxidation states and as a 7r acceptor to relieve electron density from lower metal oxidation states explains, in part, the observation that diphosphines stabilize the +3, +1, and 0 oxidation states at the expense of the +2 oxidation state.870 Vanadium(II) diphosphine halides, [V(dmpe)2X2] (dmpe = dimethyl-dimethylphosphinoethane, X = Br or I), were prepared as side products in the synthesis of [XV(CO)2(dmpe)2].885 The structurally characterized diphosphino V11 tetrahydroborate complex, tra .s-[V(BH4)2(dmpe)2], (223) was synthesized via the reduction of similar vanadium(III) precursors.832 The reaction of a vanadium(II) chloride salt with dmpe afforded the tra s-[VCl2(dmpe)2] complex which can be alkylated with MeLi or MgMe2 to afford the organometallic trans-[V(Me)2(dm pcVJ compound, which in turn reacts with thiocyanate to form tnms -[V(NCS)2(dmpe)2].8 87 Acetonitrile or propionitrile readily displace the chlorides from trans- WCl2(dmpe)2] to form // tf/ ,v-[V( NCR)2(dmpc)2][BI>h4]2 (R = Me or Et) the acetonitrile derivative reacts with HCPh(S02CF3)2 in acetonitrile solvent to yield the hexaacetonitrile species [V(NCMe)6]2+.887... 

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