2-Hydroxy-2-phenylacetamide

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Alternatively, to the solution of mandelic acid amide in dichloromethane is added 50% aqueous caustic soda at RT. Subsequently p-toluene sulfonic acid chloride (1.0 equivalent) is added as a solution in dichloromethane keeping the temperature below 25° C. The biphasic reaction mixture is stirred at RT until a satisfactory conversion is reached, phases are separated, the aqueous phase is extracted once with dichloromethane and then the combined organic phases are washed with water. After a solvent switch to toluene the solution is concentrated, cooled to 5° C. and the precipitate filtered. The crystals are washed with cooled toluene and dried in vacuo at 40° C. The biphasic reaction mixture phases are separated the aqueous phase is extracted once with dichloromethane the combined organic phases are washed with water After a solvent switch to toluene the solution is concentrated cooled to 5° C. the precipitate filtered The crystals are washed with cooled toluene dried in vacuo at 40° C.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Following Example 10 and replacing the salicylic acid with mandelic acid (1 cmole; 1.521 g) the result is a solution of the corresponding acid chloride which, when treated with ammonia gives mandelamide.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To the solution of mandelic acid amide in dichloromethane is added N-ethyldiisopropylamine (1.1 equivalents) at RT. Subsequently p-toluene sulfonic acid chloride (1.0 equivalent) is added keeping the temperature below 25° C. The reaction mixture is stirred at RT until a satisfactory conversion is reached and then washed with saturated sodium bicarbonate solution and water. After a solvent switch to ethyl acetate the solution is concentrated, cooled to −2° C. and the precipitate filtered. The crystals are washed with cooled ethyl acetate and dried in vacuo at 40° C. the temperature below 25° C washed with saturated sodium bicarbonate solution and water After a solvent switch to ethyl acetate the solution is concentrated cooled to −2° C. the precipitate filtered The crystals are washed with cooled ethyl acetate dried in vacuo at 40° C.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Yamamoto et al. (1991) tested various isolates (wildtype strains) with respect to their ability to convert mandelonitrile into (R)-(−)-mandelic acid. A. faecalis strain ATCC 8750 was found to have the highest level of activity and enantioselectivity to produce (R)-(−)-mandelic acid from racemic mandelonitrile (Yamamoto et al., 1991). In particular, the (R)-(−)-mandelic acid made of mandelonitrile by resting cells was present in a 100% enantiomeric excess. A. faecalis ATCC 8750 has an (R)-enantioselective nitrilase and an amidase used to process mandelonitrile and mandelamide, respectively. As (R)-(−)-mandelic acid was produced from racemic mandelonitrile in a yield of 91%, whereas no (S)-mandelonitrile was left, the (S)-(−)-mandelonitrile remaining in the reaction is spontaneously racemised because of the chemical equilibrium of the (R)- and the (S)-isomer of mandelonitrile on the one hand and benzaldehyde/HCN on the other hand. Consequently, almost all the mandelonitrile is consumed and converted to (R)-(−)-mandelic acid. It is noted that, according to Yamamoto et al. (1991), the A. faecalis cells employed for production of (R)-mandelic acid require specifically optimized culture conditions.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Alternatively, to the solution of mandelic acid amide in dichloromethane is added 50% aqueous caustic soda at RT. Subsequently p-toluene sulfonic acid chloride (1.0 equivalent) is added as a solution in dichloromethane keeping the temperature below 25° C. The biphasic reaction mixture is stirred at RT until a satisfactory conversion is reached, phases are separated, the aqueous phase is extracted once with dichloromethane and then the combined organic phases are washed with water. After a solvent switch to toluene the solution is concentrated, cooled to 5° C. and the precipitate filtered. The crystals are washed with cooled toluene and dried in vacuo at 40° C. The biphasic reaction mixture phases are separated the aqueous phase is extracted once with dichloromethane the combined organic phases are washed with water After a solvent switch to toluene the solution is concentrated cooled to 5° C. the precipitate filtered The crystals are washed with cooled toluene dried in vacuo at 40° C.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Following Example 10 and replacing the salicylic acid with mandelic acid (1 cmole; 1.521 g) the result is a solution of the corresponding acid chloride which, when treated with ammonia gives mandelamide.