meso-2,3-Butanediol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The title compound was prepared using 4-Acetyl-N-[4-chloro-2-(hydroxy-pyridin-4-yl-methyl)-phenyl]-benzenesulfonamide and (2R,3S)-Butane-2,3-diol following the procedure described in the preceding two examples. MS: m/z 487 M++1).

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The title compound was prepared using 4-Acetyl-N-[4-chloro-2-(hydroxy-pyridin-4-yl-methyl)-phenyl]-benzenesulfonamide and (2R,3S)-Butane-2,3-diol following the procedure described in the preceding two examples. MS: m/z 487 M++1).

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The title compound was prepared using 4-Acetyl-N-[4-chloro-2-(hydroxy-pyridin-4-yl-methyl)-phenyl]-benzenesulfonamide and (2R,3S)-Butane-2,3-diol following the procedure described in the preceding two examples. MS: m/z 487 M++1).

Conditions: temp:70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Add 4.8 ml of 12.5 N sodium hydroxide solution to a mixture of 2.68 g (29.70 mmol) (2R,3S)-butane-2,3-diol in 45 ml toluene, 15 ml 1,2-dimethoxyethane and 15 ml water at 70° C. After adding 0.20 g (0.60 mmol) tetra-n-butylammonium hydrogensulphate and 2.00 g (5.94 mmol) 4-chloro-5-(4-methoxyphenyl)-6-phenylfuro[2,3-d]pyrimidine, stir the reaction mixture for 17 h at 70° C. After cooling to room temperature, adjust to pH 7 with concentrated hydrochloric acid. Extract three times with 100 ml dichloromethane each time. Wash the combined organic extracts with satd. sodium chloride solution, dry over sodium sulphate, filter, and concentrate by vacuum evaporation. Purify the raw product by preparative RP-HPLC (gradient: water/acetonitrile). 1.26 g (54% of theor.) of the desired product is obtained as (R,S/S,R) racemate. After cooling to room temperature Extract three times with 100 ml dichloromethane each time Wash the combined organic extracts with satd sodium chloride solution, dry over sodium sulphate filter concentrate by vacuum evaporation Purify the raw product by preparative RP-HPLC (gradient: water/acetonitrile)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 3,4-dimethoxythiophene (7.2 g, 50 mmol), meso-2,3-butanediol (5.4 g, 60 mmol), and p-toluenesulphonic acid (0.2 g) in toluene (100 ml) was heated at 100° C. under a continuous argon flow for 24 h. The reaction mixture was then poured into methylene chloride (200 mL) and the organic phase washed with a 1M aqueous solution of sodium hydrogen carbonate and brine, dried with anhydrous magnesium sulphate and concentrated. This resulted in a mixture of cis and trans product that could be separated by column chromatography, yielding pure cis (2.8 g, 16%) and trans (1.83 g, 11%) 2,3-dimethyl-2,3-dihydro-thieno[3,4-b][1,4]dioxine. the organic phase washed with a 1M aqueous solution of sodium hydrogen carbonate and brine dried with anhydrous magnesium sulphate concentrated This resulted in a mixture of cis and trans product that could be separated by column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Catalyst III was installed in a reactor having a reaction tube inside diameter of 15 mm to a fill level height of 1000 mm. The oxygen content at reactor entry was automatically controlled to 4.52 vol % by addition of pure oxygen at the point of reactor entry. The reaction feed added was a mixture of 10 g/h of a racemate (equimolar mixture of R- and S-form) of acetoin (3-hydroxy-2-butanone), hereinafter referred to as acetoin, and 89.6 g/h of a stereoisomer mixture having the following composition: about 15 wt % of R,R-2,3-butanediol, about 15 wt % of S,S-2,3-butanediol, about 70 wt % of meso-2,3-butanediol, hereinafter referred to as 2,3-butanediol. For absorption, 497 g/h of water were fed in recycle gas flow direction at a point directly upstream of the column head cooler of the absorption column. The recycle gas flow was adjusted such that the reactor reached a recycle gas flow of 5800 g/h in the stable state. The reactor was operated at 11*105 Pa pressure and 180° C. coolant temperature. The reaction feed added For absorption, 497 g/h of water were fed in recycle gas flow direction at a point directly upstream of the column head cooler of the absorption column was operated at 11*105 Pa pressure and 180° C.