2,4-dimethylbenzene-1,3-diol

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and 10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107°-8° C. (Lit. 108°-109° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949).]). NMR (DMSO-d6): δ1.969 (s, 3H), 2.037 (s, 3H), 6.220 (d, J=8.1 hz, 1H), 6.637 (d, J=8.1 hz, 1H), 7.929 (s, 1H), and 8.785 (s, 1H). cooled in a 5 L 3-neck flask fitted with a magnetic stirrer the solution was sparged with nitrogen (c. 1.5 hour) was again sparged with nitrogen filtered through Celite® the resulting solution washed with water (4×100 mL) The water washes were back-extracted with ethyl acetate the combined organic layers dried over sodium sulfate

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

Procedure: To a slurry of lithium aluminum hydride (0.56 g, 14.76 mmol) in ether (35 mL) was added 1,3-diacetoxy-2,4-dimethylbenzene (the compound of Preparation 24, 1.65 g, 7.42 mmol in 40 mL of ether) via syringe. The mixture was stirred overnight; then it was carefully quenched with sodium sulfate decahydrate (excess). The mixture was dried with anhydrous sodium sulfate, filtered, and concentrated to give 0.62 g (62%) of 1,3-dihydroxy-2,4-dimethylbenzene as a waxy light yellow solid which had: NMR δ 6.83 (d, J=8 Hz, 1 H), 6.34 (d, J=8.1 Hz, 1 H), 4.71 (s, 2 H), 2.19 (s, 3 H), 2.17 (s, 3 H). There was also a small amount of an impurity observed in the NMR spectrum but the product was found to be suitable for use without further purification. The product was somewhat air sensitive and was used the same day it was synthesized. then it was carefully quenched with sodium sulfate decahydrate (excess) The mixture was dried with anhydrous sodium sulfate filtered concentrated

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

Procedure: A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and 10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107°-8° C. (Lit. 108°-109° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949).]). NMR (DMSO-d6): δ1.969 (s, 3H), 2.037 (s, 3H), 6.220 (d, J=8.1 hz, 1H), 6.637 (d, J=8.1 hz, 1H), 7.929 (s, 1H), and 8.785 (s, 1H). cooled in a 5 L 3-neck flask fitted with a magnetic stirrer the solution was sparged with nitrogen (c. 1.5 hour) was again sparged with nitrogen filtered through Celite® the resulting solution washed with water (4×100 mL) The water washes were back-extracted with ethyl acetate the combined organic layers dried over sodium sulfate

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

Procedure: A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and 10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107°-8° C. (Lit. 108°-109° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949).]). NMR (DMSO-d6): δ1.969 (s, 3H), 2.037 (s, 3H), 6.220 (d, J=8.1 hz, 1H), 6.637 (d, J=8.1 hz, 1H), 7.929 (s, 1H), and 8.785 (s, 1H). cooled in a 5 L 3-neck flask fitted with a magnetic stirrer the solution was sparged with nitrogen (c. 1.5 hour) was again sparged with nitrogen filtered through Celite® the resulting solution washed with water (4×100 mL) The water washes were back-extracted with ethyl acetate the combined organic layers dried over sodium sulfate

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

Procedure: A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and 10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107-8° C. (Lit. cooled in a 5 L 3-neck flask fitted with a magnetic stirrer the solution was sparged with nitrogen (c. 1.5 hour) was again sparged with nitrogen filtered through Celite® the resulting solution washed with water (4×100 mL) The water washes were back-extracted with ethyl acetate the combined organic layers dried over sodium sulfate

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

Procedure: To a solution of compound 8 (0.90 g, 5.9 mmol) and NaBH3CN (1.1 g, 17.7 mmol) in THF (36 mL) was slowly added 1 M HCl (17.7 mL) to keep pH of the mixture at 3. The mixture was stirred at room temperature for 3 h. Water (50 mL) was added, and then the mixture was extracted with diethyl ether (50 mL×3). The combined organic layers were dried over Na2SO4 and then evaporated. The obtained white powder (0.58 g, 70%) was used to next step without further purification. 1H-NMR (CDCl3, 400 MHz): δ6.85 (1H, d, J=8.1 Hz), 6.37 (1H, d, J=8.1 Hz), 2.22 (3H, s), 2.19 (3H, s). 13C-NMR (CDCl3, 100 MHz) δ152.8, 127.6, 115.1, 109.9, 107.0, 15.5, 8.2. the mixture was extracted with diethyl ether (50 mL×3) The combined organic layers were dried over Na2SO4 evaporated The obtained white powder (0.58 g, 70%) was used to next step without further purification

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

Procedure: A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and 10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107°-8° C. (Lit. 108°-109° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949).]). cooled in a 5 L 3-neck flask fitted with a magnetic stirrer the solution was sparged with nitrogen (c. 1.5 hour) was again sparged with nitrogen filtered through Celite® the resulting solution washed with water (4×100 mL) The water washes were back-extracted with ethyl acetate the combined organic layers dried over sodium sulfate

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

Procedure: A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and d10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107°-8° C. (Lit. 108°-109° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949).]). NMR (DMSO-d6): δ 1.969 (s, 3H), 2.037 (s, 3H), 6.220 (d, J=8.1 hz, 1H), 6.637 (d, J=8.1 hz, 1H), 7.929 (s, 1H), and 8.785 (s, 1H). cooled in a 5 L 3-neck flask fitted with a magnetic stirrer the solution was sparged with nitrogen (c. 1.5 hour) was again sparged with nitrogen filtered through Celite® the resulting solution washed with water (4×100 mL) The water washes were back-extracted with ethyl acetate the combined organic layers dried over sodium sulfate

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

Procedure: A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and 10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107°-8° C. (Lit. 108°-109° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949).]). cooled in a 5 L 3-neck flask fitted with a magnetic stirrer the solution was sparged with nitrogen (c. 1.5 hour) was again sparged with nitrogen filtered through Celite® the resulting solution washed with water (4×100 mL) The water washes were back-extracted with ethyl acetate the combined organic layers dried over sodium sulfate

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

Procedure: A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and d10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107°-8° C. (Lit. 108°-109° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949).]). NMR (DMSO-d6): δ 1.969 (s, 3H), 2.037 (s, 3H), 6.220 (d, J=8.1 hz, 1H), 6.637 (d, J=8.1 hz, 1H), 7.929 (s, 1H), and 8.785 (s, 1H). cooled in a 5 L 3-neck flask fitted with a magnetic stirrer the solution was sparged with nitrogen (c. 1.5 hour) was again sparged with nitrogen filtered through Celite® the resulting solution washed with water (4×100 mL) The water washes were back-extracted with ethyl acetate the combined organic layers dried over sodium sulfate

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

Procedure: A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and d10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107°-8° C. (Lit. 108°-109° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949).]). NMR (DMSO-d6): δ 1.969 (s, 3H), 2.037 (s, 3H), 6.220 (d, J=8.1 hz, 1H), 6.637 (d, J=8.1 hz, 1H), 7.929 (s, 1H), and 8.785 (s, 1H). cooled in a 5 L 3-neck flask fitted with a magnetic stirrer the solution was sparged with nitrogen (c. 1.5 hour) was again sparged with nitrogen filtered through Celite® the resulting solution washed with water (4×100 mL) The water washes were back-extracted with ethyl acetate the combined organic layers dried over sodium sulfate