Pentachloride complexes

The 1,4-diketone 1,2-dibenzoylethane 151 can be transformed in one step into 3,4-dibenzoyl-l,2,5-thiadiazole 152 when treated either with preformed trithiazyl trichloride in tetrachloromethane (Equation 29) <1997J(P1)2831> or with urethane, thionyl chloride, and pyridine in benzene (Katz reagent) <2002ARK90> (see also Section 5.09.9.2.l(iii)(b)). Similarly, treatment of 1,3-diketones 153 with tetrasulfur tetranitride antimony pentachloride complex in toluene at 100 °C < 1998J(P 1 )2175 >, or trithiazyl trichloride in boiling tetrachloromethane < 1997J(P 1)2831 >, affords 4-substituted-3-aroyl-l,2,5-thiadiazoles 154 (Equation 30). 

Enamines 187 with electron-withdrawing groups in the /3-position are converted into thiadiazoles 188 in moderate yields (50-60%) on treatment with either tetrasulfur tetranitride antimony pentachloride complex <2000H(53)159> or trithiazyl trichloride <2001J(P1)662> (Equation 38 Table 12). Cyclization onto electrophilic /3-substituents was not observed, and thus the procedure offers a regiospecific synthesis of 4-substituted-3-aroyl-l,2,5-thiadiazoles. 

Unlike the reaction of alkyl aryl ketoximes with tetrasulfur tetranitride <1996CHEC-II(4)355>, the treatment of alkyl methyl ketoximes 189 with tetrasulfur tetranitride antimony pentachloride complex in either benzene or toluene at 50-80°C gave low yields (3-37%) of 3-alkyl-4-methyl-l,2,5-thiadiazoles 190 (Equation 39) <1999H(50)147>. Compounds 190 were volatile and the low yields are in part attributed to their loss as the solvent was removed in vacuo. Suprisingly, only single regioisomers were obtained. 3-Heptanone oxime 191 did, however, give a mixture of two isomers 192 and 193 (Equation 40). 

Reaction of tetrasulphur tetranitride antimony pentachloride complex (S4N4.SbCl5) with a series of primary (3-enaminones and P-enamino esters 79 in toluene at 100 °C gave reasonable yields of 3,4-disubstituted 1,2,5-thiadiazoles 80. The formation of 80 was explained by the same mechanism as that proposed for the formation of 1,2,5-thiadiazoles from 3,5-disubstituted isoxazoles with S4N4.SbCl5 complex <00H159>. 

Antimony pentachloride complexes of A-oxides of pyridine, quinoline and isoquinoline rearrange on heating to give the corresponding pyrid-2-one, carbostyril or isocarbostyril, e.g. Scheme 118 (81T1871). 

Cyclic S-N compounds including S2N2 have been reviewed. An x-ray analysis of disulfur dinitride, S2N2, with alternating sulfur and nitrogen atoms indicates a nearly square planar array with S-N distances of 1.657 and 1.651 A and angles NSN of 89.6° and SNS of 90.4°. The structure of the bis(antimony pentachloride) complex is planar S-N, 1.619 A NSN, 84.9° SNS, 95.1°. An S2N2 complex of copper (II) chloride also is planar S-N, 1.633, 1.641 A N-S-N,... 

Divinyl ether itself presents a fairly complex case one detailed study claimed that the decomposition of the ether-phosphorus pentachloride complex with SO2 yields the phosphonic dichlorides 78-80 together with vinyl dichlorophosphate whilst a more recent study demonstrated that treatment of the intermediate complex with SO2 yielded 81, and with Asp3 yielded 82 in each case, a co-product was [2-(l-chloroethoxy)vinyl]phosphon-ic dichloride (78). The action of phosphorus pentachloride on the sulphide 83 presumably proceeds through 84, although in the work-up procedures thus far adopted, dehydrohalo-genation occurs to give 85 (R = Cl) ... 

The salts of the parent compound Cl2C=NH (IV) were synthesized by Allenstein and Schmidt ( ) in 1964, by adding hydrogen chloride to the antimony pentachloride complexes of cyanogen halides V. The compounds obtained (IV) are stable at room temperature, with the exception of the iodine derivative (IV, X=I)( ). 

Bae S-H, Kim K, ParkYJ (2000) Reactions of tetrasulfur tetranitride antimony pentachloride complex (S4N4 SbCls) with primary p-enaminones and p-enamino esters synthesis of... 

Nogaj B, Poleshchuk OKh, Kasprzak J, Koput J, EHnVP, Dolenko GN (1997)Changes in electron density distribution resulting from formation of antimony pentachloride complexes studied by X-ray fluorescence spectroscopy. Journal of Molecular Structure 406-. 145-151. 

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