0- benzophenone cyanohydrin

Benzaldehyde, 43, 73, 123 Benzaldehyde diethyl acetal, 108, 110,122—3 Benzaldehyde dimethyl acetal, 34, 111 Benzenesulphonylhydrazonc, 13 Benzophenone, 137 Benzophenone cyanohydrin, 137 p-Benzoquinone, 137... 

Trimethylsilyl)benzophenone cyanohydrin has been prepared previously by the addition of trimethylsilyl cyanide to benzophenone using an aluminum chloride catalyst.4 The preparation of cyanohydrin silyl ethers described in the synthesis is based on... 

Trimethylsilyl)benzophenone cyanohydrin Benzeneacetoni-trile, a-phenyl-a-(trimethylsiloxy)- (8) Benzeneacetonitrile, a-phenyl-a-[(trimethylsilyl)oxy]- (9) (40326-25-8)... 

A. 0-(Trimethylsilyl)benzophenone cyanohydrin. A 250-mL, one-necked flask equipped with a reflux condenser, magnetic stirring bar, and drying tube is charged with 22.0 g (0.12 mol) of ben-zophenone (Note 1), 13.9 g (0.14 mol) of trimethylsilyl cyanide (Note 2), 600 mg (1.9 mmol) of anhydrous zinc iodide (Note 3), and 50 mL of dry methylene chloride (Note 4). The solution is heated at 65°C in an oil bath for 2 hr (Notes 5 and 6). The solvent is removed on a rotary evaporator to yield 36.4-37.9 g of crude product (Note 7), which is used in the next step without purification (Note 8). 

B. Benzophenone cyanohydrin. To the 250-mL flask, which contains the crude 0-(trimethylsilyl)benzophenone cyanohydrin, is added 50 mL of tetrahydrofuran (Note 9), and 30 mL of 3 N hydrochloric acid. The mixture is heated at 65°C (oil bath temperature) for 1 hr. The solution is poured into a separatory funnel and 30 mL of water is added. The aqueous phase is separated and back-extracted with three 100-mL portions of diethyl ether. The ethereal extracts are combined with the tetrahydrofuran solution and dried over anhydrous magnesium sulfate, filtered, and the solvent is removed by evaporation on a rotary evaporator to give a yellow solid. The material is recrystallized from 300 mL of toluene and dried at a pressure of 0.05 mm overnight to give 17.7-18.8 g of white crystals. Concentration of the mother liquors to 100 mL produced a second crop of 1.1-3.8 g for a combined yield of 17.9-21.5 g (79-86%), mp 127-130°C (Note 10). 

Benzophenone cyanohydrin has been synthesized previously by the nitrogen dioxide oxidation of 1,2-dicyanotetraphenylethane.2... 

The conjugate hydrocyanation of rather unreactive chalcone-type enones RCH=CHCOAr, employing benzophenone cyanohydrin Ph2C(CN)OH as a precursor of HCN, and catalysed by the sodium salt generated in situ from NaNH2 and the... 

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