Benzyl thiocyanate

Moreover, product formation was not the same. Dibenzyl ethylsulfonium salt 72 gave only benzyl ethyl sulfide (73) and benzyl thiocyanate 74, but no dibenzyl sulfide or ethyl thiocyanate. By contrast, the cyclic sulfonium salt 75 gave a mixture containing chiefly (80%) dihydroisothianaphthene (76) with an equivalent amount of ethyl thiocyanate (77) and a minor amount (20%) of the sulfide-thiocyanate 78. This work represents the first direct experimental information on the rate of bimolecular nucleophilic substitution and relative orientation of the benzene ring and the leaving group and it demonstrates clearly the importance of stereoelectronic effects in these reactions. 

A situation of this type was encountered in the investigation of the solvolysis of benzyl azoxytosylate, 14 in Fig. 9.6, in aqueous trifluoroethanol [23]. In the absence of added nucleophilic reagents the products were benzyl alcohol and benzyl trifluoroethyl ether. Added excess sodium thiocyanate had minimal effect upon the rates, but the reaction then yielded substantial amounts of benzyl thiocyanate. The plot of the inverse mole fraction of benzyl thiocyanate against 1/ [NaSCN], shown in Fig. 9.6, is linear with a non-zero intercept, consistent with the intermediacy of a species trappable by thiocyanate, and a competing pathway for the formation of ethereal and alcoholic products other than via this species. 

Agbalyan et al 9 recently employed this reaction in the synthesis of several 3,4-dihydroisoquinoline derivatives with unsaturated substituents in the 1-position. The Madrid group50 has shown that (with the exception of benzyl thiocyanate) aliphatic and aromatic thiocyanates yield 1-alkylthio- and l-arvlthio-3,4-dihydroisoquinolines as expected (cf. Table V). 

Only preliminary details have been reported of the reversible photoisomerization of benzyl thiocyanate and isothiocyanate ... 

Synergists do not have to contain the MDP grouping. Other compounds showing similar activity include aryl propynyl ethers, propynyl oxime ethers, propynyl phosphorate esters and benzyl thiocyanates. 

Triphasic systems involving clays pillared with surfactants as catalysts offer versatile routes to a range of useful benzylic compounds.40 By using the organo-clay assemblies with sodium cyanide, thiocyanate and hydroxide, it is possible to prepare benzonitriles, benzyl thiocyanates and benzyl alcohols from the corresponding benzyl chlorides. Most of these reactions occur in yields of ca. 80%. 

Short reference will be made to the decomposition of benzylazoxy-4-toluenesulfo-nate (7.21) studied by Maskill s group (Maskill, 1980 Maskill and Jencks, 1984,1987 Conner and Maskill, 1988 Gordon and Maskill, 1989, and further papers mentioned there). As shown in (7-9), this reaction also leads to solvolysis products of car-bocations, but with nitrous oxide as a leaving group rather than an N2 molecule. The intermediacy of an alkoxydiazonium ion (7.22) is postulated on the observation that considerable amounts of benzyl thiocyanate (7.23) and some benzaldehyde... 

Labelled cyanogen bromide ( CNBr) has been used by Westerberg and Langstrom to synthesize several aromatic cyanates, and cyanamides, a 1-cyanopyridinium bromide and phenyl and benzyl thiocyanates in good yields in a few minutes (Scheme 5). The yields for each reaction are in the parentheses. 

The production of many secondary metabolites is stimulated by effectors which exert an induction effect. The effect of benzyl thiocyanate, stimulator of chlortetra-cycline biosynthesis (3), was investigated at the enzyme level. At a concentration of 2,10 °M, the agent increases the level of anhydrotetracycline hydratase (catalyzing the hydration of anhydrotetracycline to 5a,lla-dehy-drotetracycline) in Streptomyces aureofaciens (4). 

The inhibitory effect of inorganic phosphate on biosynthetic pathways of secondary metabolites including non--phosphorylated intermediates is explained less readily. The action usually involves the derepression of synthesis of enzymes which carry out the formation of secondary products after the inorganic phosphate has been exhausted (4). The study by Martin et al. (23) of the effect of orthophosphate on candicidin biosynthesis in Streptomyces griseus suggested that inorganic phosphate either inhibits the activity of candicidin synthases or represses their synthesis (24). Inorganic phosphate also represses the synthesis of anhydrotetracycline hydratase in Streptomyces aureofaciens while benzyl thiocyanate abolishes its inhibitory effect (4). 

HCl bubbled 2 hrs. through a refluxing soln. of 0,0-diethyl hydrogen phos-phorodithioate and benzyl thiocyanate as HgS-acceptor 0,0-diethyl phos-phorochloridothionate. Y 85%. F. e. and H2S-acceptors s. N. A. Meinhardt, S. Z. Cardon, and P. W. Vogel, J. Org. Chem. 25, 1991 (1960). 

Hydrogen exchange with the a-carbon-protons of the co-ordinated amino-acids in [Mo(A -C6H5)2(amino-acid)] could involve a carbanion or an oxazolonium ion intermediate. Whereas benzyl thiocyanate... 

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