Pyridine selenocyanates

Complexes with pyridine JV-oxide of zinc thiocyanate and selenocyanate of the stoichiometry ZnLsX2 (X = SCN, SeCN) have been reported.1066 IR evidence shows that they are best formulated as [ZnL6]2+[ZnX4f. ... 

Several amines such as anilines, pyridine, etc., were perfluoroalkylated affording the corresponding ammonium or pyridinium salts [26-28], Other substrates which underwent perfluoroalkylation included triphenylphosphine [26], sodium nitrite [29], potassium thiocyanate [29] and potassium selenocyanate [29]. 

Nucleophiles containing elements of the second row have also been used in photosubstitution reactions of aryl halides. The selenocyanate ion739, selenourea740 and thiourea741 are capable of replacing halogen atoms in various derivatives of benzene, naphthalene, pyridine and pyrimidine. Both chlorine atoms in 6>rj/zc>-dichlorobenzene are substituted upon irradiation in (MeO)3P at 60 °C for 5 days and a 50% yield of 1,2-bis(phosphino)-benzene is obtained742. 

ALKYL SELENOCYANATES Triphenyl-phosphine-Diethyl azodicarboxylate. ALKYNES Acetic anhydride-Pyridine. Dimethyl) diazomethyl)phosphonate. OrganoUthium reagents. 

NaBH4 has been found to be an effective reducing agent for the reduction of both thiocyanates (in DMF at 25 C) - - and selenocyanates (in pyridine at 25 °C). A procedure for the reduction of thiocyanates using tributyltin hydride (equation 30) has been reported by Ueno et The mechanism of the reduction is probably homolytic and the thiostannanes (15) formed are stable and can be readily isolated. The thiostannanes, in addition to being more pleasant to handle than the parent thiols, can be converted into typical thiol derivatives, such as thiol esters, in excellent yields. 

Oxyselenation of alkenes (8, 119-120). Details of this reaction have been published. The role of the metal catalyst is considered to be polarization of the Se— CN bond of the selenocyanate, and in fact the pyridine complex of the metal salt is less effective. An episelenonium ion is postulated as the intermediate. CuBr2, CiCl, NiBr2, and NiCl2 are similar to CuCl2 in activity. CrCl3 and CoCl2 show limited activity, whereas halides of many other metals are inactive. 

Dichlorosilicon phthalocyanine (XIX) is prepared from silicon tetrachloride and phthalonitrile in quinoline at 200°C 168,170). The blue-green crystals, which sublime readily at 430°C in vacuo, hydrolyze forming dihydroxysilicon phthalocyanine (XX) when refluxed with equal volumes of pyridine and aqueous ammonia (200). The corresponding difluorosilicon phthalocyanine is resistant to hydrolysis. Conversion of the chloride to the corresponding dicyanate, dithiocyanate, and diselenocyanate occurs upon reaction with the appropriate silver pseudohalide (178). The complexes are believed to involve nitrogen to silicon bonding in the case of the thiocyanate and selenocyanate. 

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