Phenyl chlorothionoformate

A soln of 1.4 M BuLi in hexane (6.79 mL, 9.51 mmol) was added dropwise by syringe to a stirred soln of the diethyl (f S)-2-[(4f )-3-(tert-butoxycarbonyl)-2,2-dimethyloxazolidin-4-yl]-l,l-difluoro-2-hydroxy-ethylphosphonate (3.96 g, 9.51 mmol) in dry THF (50 mL) at —78 °C followed immediately by the addition of phenyl chlorothionoformate (1.97 mL, 14.3 mmol). After 15 min at —78 °C, a soln of NaHC03 (25 mL) was added and extracted with Et20 (4x 5mL). The combined organic extracts were dried (MgS04), filtered, and the solvent removed under reduced pressure. The residue was purified by flash chromatography (silica gel, EtOAc/hexane 10 90 to 30 70) to give the pure product yield 4.05 g (79%). 

N,N-Dimethylaniline n-Pentyl nitrite Phenyl chlorothionoformate 4-Dimethylaminopyridine Tri-n-butyltin hydride... 

Phenyl chlorothionoformate (4.66 g, 27 mM) is added to a mixture of 2-chloro-(3, 5 -0-tetraisopropyldisiloxyl)adenosine (14 g, 25.8 mM), 4-dimethylaminopyridine (DMAP) (6.88 g, 56.4 mM) and acetonitrile (400 mL) at room temperature under nitrogen, and stirred overnight. The solvent is removed in vacuo and the residue is purified by column chromatography on silica gel (200 g) with ethyl acetate/hexane (4 6) to yield the title compound as a pale yellow powder (9.8 g, 56%, MP 153-155°C). NMR, IR and elemental analysis are confirmed the structure of the title compound. 

Oxidative functionalization of imidazoles is typically not preparatively useful. However, an optimized procedure for direct peracid oxidation of azoles to N-hydroxyazoles was reported [95JCS(P1)243], with imidazoles affording dioxygenated products. In contrast, imidazoles are conveniently converted to imidazole-2-thiones with phenyl chlorothionoformate [95SL239]. 

Phenyl chlorothionoformate Formic acid, chlorothio-, O-phenyl ester (8) Carbonochloridothioic acid, O-phenyl ester (9) (1005-56-7)... 

Phenyl chlorothionoformate (Aldrich Chemical Company, Inc., 99%) was used without purification. 

The resulting 2-hydroxy-1,1-difluoroalky Iphosphonates can be submitted to PDC or Swern oxidation to give 2-oxo-1,1-difluoroalkyIphosphonates in 56-94% yields" or treated with phenyl chlorothionoformate and then deoxygenated with n-llihSnll to produce the reduced 1,1-difluoro-alkylphosphonates in good yields (68-89%) ... 

DEHYDRATION Boron trioxide. p-CMoro-phenyl chlorothionoformate. Dicyclohexyl-carbodiimide. Diethyl(2-chloro-l,l,2-tri-fluoroethyOaminc. Phosphoryl chloride N -Dimethylformamide. Polyphosphate ester. Pyridine hydrochloride. 

Treatment of 2-methyl-l-penten-3-ol with phenyl chlorothionoformate leads to a 96.5 3.5 EjZ mixture of the rearranged product 1 in 67% yield308. The reaction of 2-methyl-l-penten-3-ol with phenyl dithiochloroformate gives 5-2-methyl-2-pentenyl 5-phenyl dithiocarbonate (2) in 30% yield and >99% 308. 

A solution of 1.2 g (1.2 mmol) of 2-methyl-l-penten-3-ol in 10mL of pyridine is cooled to — 20 °C, and 2.2 g (1.28 mmol) of phenyl chlorothionoformate are added with stirring. After 1 h the product is poured into H20, and the organic material is extracted with Et20. The ethereal layers are washed with 2 N NaOH, H20, 3 N HC1, and H20 again. The combined ethereal layers are dried over anhyd Na2S04, and the solvent is evaporated. The residue is distilled to obtain the thiolcarbonate as a pale yellow oil vield 1.77 g (67%) bp 110°C/1 Torr. 

A rather new method for the preparation of aromatic and aliphatic nitriles from amides on various structures, under mild conditions and with a simple work-up, was published in 1999. The reagent is phenyl chlorothionoformate, the reactions are performed at room temperature, reaction times are 5-9 h, and yields are high (81-95%) [1130]. 

General procedure. Nitriles from carboxamides (or thiocarboxamides) [1130] Phenyl chlorothionoformate (1.1 mmol) was added dropwise to a stirred, ice-cooled solution (or suspension) of the amide (1.0 mmol) in dry dichloromethane (5 mL) and anhydrous pyridine (2.0 mmol) at such a rate that the temperature was kept below 5 °C. The reaction mixture was then allowed to warm to room temperature for the requisite time and was then quenched with water (2 mL). The resulting mixture was extracted with dichloromethane (2 x 15 mL). The combined organic phases were washed with saturated brine, dried (Na2S04), and the solvent was removed in vacuo to afford the crude product, which was purified by column chromatography on silica gel. Pure nitriles were obtained in yields of 80-95%. 

Phenyl chlorothionoformate is presented as a versatile reagent for the preparation of nitriles and isonitriles under mild conditions [1130]. A general procedure is given for cyanides (see Section 4.5.1). Benzyl isocyanide and trrmethoxybenzyl isocyanide have also been prepared according to this procedure within 7.5-10 h at room temperature in yields of 82 and 85% [1130]. 

Cyanopyridine 23 has been prepared from nicotinic amide by several methods, in good to excellent yidd in each case. As dehydration reagents, phenyl chloroformate [28], phenyl chlorothionoformate [29], oxalyl chloride/DMSO [30], triflic anhydride [31], and the Burgess reagent [32] have been used, giving yields of 23 of 92%, 92%, 75%, 93%, and 92%, respectively. 

The specific rates of solvolysis of phenyl chlorothionoformate (PhOCSCl) were found to be remarkably similar to those reported previously for phenyl chlorothioformate (PhSCOCl). When analysed using the extended Grunwald-Winstein equation over the usual range of solvent types, these solvolyses showed essentially identical divisions... 

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