Diphenyl, sulfur analogues

The reaction of sulfur dichloride with benzonitrile in the presence of a Lewis acid catalyst yields 3,5-diphenyl-l,2,4-thiadiazole (39), along with the 3-o-chlorophenyl (278) and 3-p-chlorophenyl (279) analogues in a total yield of 80%. The proposed mechanism proceeds via a complex between benzonitrile, Lewis acid for example, aluminum trichloride, and sulfur dichloride to give an intermediate (280) which then adds a second molecule of nitrile (Scheme 62) <83BCJ180>. 

Chloro-3-methylpyrazine (101,535) and 2-chloro-5-phenylpyrazine (363, 365a, 377, 824, 825) have been prepared from the corresponding hydroxy compound and phosphoryl chloride, 2-chloro-6-methylpyrazine from 2-hydroxy-6-methylpyrazine and phosphoryl chloride with one drop of dimethylformamide (681), and 2-benzyl(or s-butyl, isobutyl, or isopropyl)-3phosphoryl chloride with a trace of concentrated sulfuric acid (80). 2-Chloro-6-methyl-3-propyl- (826), 3[Pg.99]

Cyclic Monophosphates and Their Analogues. - A new preparative route to cyclic phosphorothioates of type 199 involves the reaction of 5 -0-Dmtr-nucleo-sides with diphenyl H-phosphonate in the presence of pyridine, followed by treatment of the resultant cyclic H-phosphonates with sulfur and final deprotection with acetic acid. The method was used with all four ribonucleobases, and gave the products as 1 1 mixtures of diastereoisomers. ... 

Matrix investigations of sulfur and phosphorus analogues of acarbonylcarbenes have also been reported. For example, diphenylsulfene (66) and diphenyl-a-sultine (67) were isolated in low-temperature matrices following the thermal reaction of SO2 and diphenylcarbene (65) and the stepwise photolysis of phenyl(phenylsulfonyl)diazomethane (68), as summarized in Scheme 8. The ultimate photoproduct was benzophenone (70). 

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