Proscaline synthesis
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This is from Shulgin's PIHKAL book:
-PROPOXYPHENETHYLAMINE
SYNTHESIS: A solution of 5.8 g of homosyringonitrile (see under E for its synthesis), 100 mg decyltriethylammonium iodide, and 10 g n-propyl bromide in 50 mL anhydrous acetone was treated with 6.9 g finely powdered anhydrous K2CO3 and held at reflux for 10 h. An additional 5 g of n-propyl bromide was added to the mixture, and the refluxing continued for another 48 h. The mixture was filtered, the solids washed with acetone, and the combined filtrate and washes stripped of solvent under vacuum. The residue was suspended in acidified H2O, and extracted 3x175 mL CH2Cl2. The pooled extracts were washed with 2x50 mL 5% NaOH, once with dilute HCl (which lightened the color of the extract) and then stripped of solvent under vacuum giving 9.0 g of a deep yellow oil. This was distilled at 132-142 °C at 0.3 mm/Hg to yield 4.8 g of 3,5-dimethoxy-4--propoxyphenylacetonitrile as a clear yellow oil. Anal. (C13H17NO3) C H N.
A solution of 4.7 g 3,5-dimethoxy-4--propoxyphenylacetonitrile in 20 mL THF was treated with 2.4 g powdered sodium borohydride. To this well-stirred suspension there was added, dropwise, 1.5 mL trifluoroacetic acid. There was a vigorous gas evolution from the exothermic reaction. Stirring was continued for 1 h, then all was poured into 300 mL H2O. This was acidified cautiously with dilute H2SO4, and washed with 2x75 mL CH2Cl2. The aqueous phase was made basic with dilute NaOH, extracted with 2x75 mL CH2Cl2, the extracts pooled, and the solvent removed under vacuum. The residue was distilled at 115-125 °C at 0.3 mm/Hg to give 1.5 mL of a colorless oil which upon dissolving in 5 mL IPA, neutralizing with 27 drops concentrated HCl, and dilution with 25 mL anhydrous Et2O yielded 1.5 g 3,5-dimethoxy-4--propoxyphenethylamine hydrochloride (P) as spectacular white crystals. The catalytic hydrogenation process for reducing the nitrile (see under E) also succeeded with this material. The mp was 170-172 °C. Anal. (C13H22ClNO3) C,H,N.
(see first line of SYNTHESIS above to see why this next is included)
SYNTHESIS: To a solution of 72.3 g 2,6-dimethoxyphenol in 400 mL MeOH, there was added 53.3 g of a 40% solution of aqueous dimethylamine folowed by 40 g of a 40% aqueous solution of formaldehyde. The dark solution was heated under reflux for 1.5 h on a steambath. The volatiles were then removed under vacuum yielding a dark oily residue of 2,6-dimethoxy-4-dimethylaminomethylphenol. This residue was dissolved in 400 mL of IPA, to which there was added 50 mL of methyl iodide. The spontaneously exothermic reaction deposited crystals within 3 min, and was allowed to return to room temperature and occasionally stirred over the course of 4 h. The solids were removed by filtration, washed with cold IPA, and allowed to air dry yielding 160 g of the methiodide of 2,6-dimethoxy-4-dimethylaminomethylphenol as a cream-colored crystalline solid.
A suspension of 155 g of the above methiodide of 2,6-dimethoxy-4-dimethylaminophenol in 600 mL H2O was treated with a solution of 130 g KCN in 300 mL H2O. The reaction mixture was heated on a steam bath for 6 h during which time there was a complete dissolving, the development of a brownish color with a bright blue film on the surface and the walls of the flask, and the gentle evolution of fine gas bubbles. The hot reaction mixture was poured into 1.2 L H2O and acidified with concentrated HCl (careful, HCN evolution). The aqueous solution was extracted with 3x150 mL CH2Cl2, the extracts pooled, washed with saturated NaHCO3 which removed much of the color. The solvent was removed under vacuum yielding about 70 g of a viscous black oil. This was distilled at 0.4 mm/Hg at 150-160 °C to provide 52.4 g of homosyringonitrile (3,5-dimethoxy-4-hydroxyphenylacetonitrile) as a white oil that spontaneously crystallized to lustrous white crystals that melted at 57-58 °C.
A solution of 5.75 g of homosyringonitrile and 12.1 g ethyl iodide in 50 mL dry acetone was treated with 6.9 g finely powdered anhydrous K2CO3 and held at reflux for 18 h. The mixture was diluted with 100 mL Et2O, filtered, and the filtrate solvent removed under vacuum The residue was recrystallized from Et2O/hexane to yield 5.7 g 3,5-dimethoxy-4-ethoxyphenylacetonitrile with a mp 57-58 °C. Anal. (C12H15NO3) C,H,N.
A solution of 2.21 g 3,5-dimethoxy-4-ethoxyphenylacetonitrile in 25 mL EtOH containing 2.5 mL concentrated HCl and 400 mg 10% palladium on charcoal, was shaken in a 50 lb/sq.in. atmosphere of hydrogen for 24 h. Celite was added to the reaction suspension and, following filtration, the solvents were removed under vacuum. The residue was recrystallized from IPA/Et2O to yield 2.14 g 3,5-dimethoxy-4-ethoxyphenethylamine hydrochloride (E) with a mp of 166-167 °C.
Synthesis from syringaldehyde: A well-stirred suspension of 21.9 g syringaldehyde in 45 mL H2O was heated to reflux in a heating mantle. There was then added a solution of 15 g NaOH in 60 mL H2O. The heating and stirring was continued until the generated solids redissolved. Over a period of 10 min, there was added 23 g diethyl sulfate, then refluxing was continued for 1 h. Four additional portions each of 5 g diethyl sulfate and of 6 mL 20% NaOH were alternately added to the boiling solution over the course of 2 h. The cooled reaction mixture was extracted with Et2O, the extracts pooled and dried over anhydrous MgSO4, decolorized with Norite, and stripped of solvent. The crude 3,5-dimethoxy-4-ethoxy-benzaldehyde weighed 21.8 g and melted at 51-52 °C.
A solution of 14.7 g 3,5-dimethoxy-4-ethoxybenzaldehyde and 7.2 mL nitromethane in 50 mL glacial acetic acid was treated with 4.4 g anhydrous am-monium acetate and held at reflux for 30 min. Cooling the reaction allowed the formation of yellow crystals which were removed by filtration and washed sparingly with cold acetic acid. The dried 3,5-dimethoxy-4-ethoxy-beta-nitrostyrene weighed 11.5 g and melted at 108-109 °C after recrystallization from EtOH Anal. (C12H15NO5) C,H. Alternately, this product may be prepared from 3.9 g. 3,5-dimethoxy-4-ethoxybenzaldehyde in 60 mL nitromethane containing 0.7 g ammonium acetate and heated on a steam bath for 1 h. The solvent was removed under vacuum, and the residue dissolved in a minimum of hot MeOH. Cooling provided, after filtration and air drying, 2.3 g of bright yellow crystals of 3,5-dimethoxy-4-ethoxy-beta-nitrostyrene, with a mp of 105-107 °C.
A solution of 2.25 g LAH in 45 mL anhydrous THF was vigorously stirred and cooled to 0 °C under He. There was added 1.5 mL 100% H2SO4 dropwise, followed by 2.3 g 3,5-dimethoxy-4-ethoxy-beta-nitrostyrene in anhydrous THF. After the addition was complete, the mixture was allowed to stir for 30 min, and then brought to room temperature. The unreacted hydride was decomposed with 2.3 mL H2O in THF, followed by the addition of 9.2 mL of 15% NaOH. The white suspension was filtered, the filter cake was washed with THF, the filtrate and washings combined, and the solvent removed under vacuum. The residue was dissolved in 300 mL dilute H2SO4, washed with 2x75 mL CH2Cl2, made basic with 25% NaOH, and the product extracted with 3x75 mL CH2Cl2. After removal of the solvent, the residue was distilled at 110-120 °C at 0.3 mm/Hg yielding 1.4 g of a colorless oil. A solution of this oil in 20 mL IPA was neutralized with 17 drops of concentrated HCl and diluted with 100 mL anhydrous Et2O. After a few minutes there was the spontaneous formation of white crystals of 3,5-dimethoxy-4-ethoxyphenethylamine hydrochloride (E) which was recrystallized from 40 mL boiling EtOAc containing 1 mL MeOH. The mp was 165-166 °C.
#140 P
PROSCALINE; 3,5-DIMETHOXY-4--PROPOXYPHENETHYLAMINESYNTHESIS: A solution of 5.8 g of homosyringonitrile (see under E for its synthesis), 100 mg decyltriethylammonium iodide, and 10 g n-propyl bromide in 50 mL anhydrous acetone was treated with 6.9 g finely powdered anhydrous K2CO3 and held at reflux for 10 h. An additional 5 g of n-propyl bromide was added to the mixture, and the refluxing continued for another 48 h. The mixture was filtered, the solids washed with acetone, and the combined filtrate and washes stripped of solvent under vacuum. The residue was suspended in acidified H2O, and extracted 3x175 mL CH2Cl2. The pooled extracts were washed with 2x50 mL 5% NaOH, once with dilute HCl (which lightened the color of the extract) and then stripped of solvent under vacuum giving 9.0 g of a deep yellow oil. This was distilled at 132-142 °C at 0.3 mm/Hg to yield 4.8 g of 3,5-dimethoxy-4-
-propoxyphenylacetonitrile as a clear yellow oil. Anal. (C13H17NO3) C H N.A solution of 4.7 g 3,5-dimethoxy-4-
-propoxyphenylacetonitrile in 20 mL THF was treated with 2.4 g powdered sodium borohydride. To this well-stirred suspension there was added, dropwise, 1.5 mL trifluoroacetic acid. There was a vigorous gas evolution from the exothermic reaction. Stirring was continued for 1 h, then all was poured into 300 mL H2O. This was acidified cautiously with dilute H2SO4, and washed with 2x75 mL CH2Cl2. The aqueous phase was made basic with dilute NaOH, extracted with 2x75 mL CH2Cl2, the extracts pooled, and the solvent removed under vacuum. The residue was distilled at 115-125 °C at 0.3 mm/Hg to give 1.5 mL of a colorless oil which upon dissolving in 5 mL IPA, neutralizing with 27 drops concentrated HCl, and dilution with 25 mL anhydrous Et2O yielded 1.5 g 3,5-dimethoxy-4--propoxyphenethylamine hydrochloride (P) as spectacular white crystals. The catalytic hydrogenation process for reducing the nitrile (see under E) also succeeded with this material. The mp was 170-172 °C. Anal. (C13H22ClNO3) C,H,N.(see first line of SYNTHESIS above to see why this next is included)
#72 E; ESCALINE
3,5-DIMETHOXY-4-ETHOXYPHENETHYLAMINESYNTHESIS: To a solution of 72.3 g 2,6-dimethoxyphenol in 400 mL MeOH, there was added 53.3 g of a 40% solution of aqueous dimethylamine folowed by 40 g of a 40% aqueous solution of formaldehyde. The dark solution was heated under reflux for 1.5 h on a steambath. The volatiles were then removed under vacuum yielding a dark oily residue of 2,6-dimethoxy-4-dimethylaminomethylphenol. This residue was dissolved in 400 mL of IPA, to which there was added 50 mL of methyl iodide. The spontaneously exothermic reaction deposited crystals within 3 min, and was allowed to return to room temperature and occasionally stirred over the course of 4 h. The solids were removed by filtration, washed with cold IPA, and allowed to air dry yielding 160 g of the methiodide of 2,6-dimethoxy-4-dimethylaminomethylphenol as a cream-colored crystalline solid.
A suspension of 155 g of the above methiodide of 2,6-dimethoxy-4-dimethylaminophenol in 600 mL H2O was treated with a solution of 130 g KCN in 300 mL H2O. The reaction mixture was heated on a steam bath for 6 h during which time there was a complete dissolving, the development of a brownish color with a bright blue film on the surface and the walls of the flask, and the gentle evolution of fine gas bubbles. The hot reaction mixture was poured into 1.2 L H2O and acidified with concentrated HCl (careful, HCN evolution). The aqueous solution was extracted with 3x150 mL CH2Cl2, the extracts pooled, washed with saturated NaHCO3 which removed much of the color. The solvent was removed under vacuum yielding about 70 g of a viscous black oil. This was distilled at 0.4 mm/Hg at 150-160 °C to provide 52.4 g of homosyringonitrile (3,5-dimethoxy-4-hydroxyphenylacetonitrile) as a white oil that spontaneously crystallized to lustrous white crystals that melted at 57-58 °C.
A solution of 5.75 g of homosyringonitrile and 12.1 g ethyl iodide in 50 mL dry acetone was treated with 6.9 g finely powdered anhydrous K2CO3 and held at reflux for 18 h. The mixture was diluted with 100 mL Et2O, filtered, and the filtrate solvent removed under vacuum The residue was recrystallized from Et2O/hexane to yield 5.7 g 3,5-dimethoxy-4-ethoxyphenylacetonitrile with a mp 57-58 °C. Anal. (C12H15NO3) C,H,N.
A solution of 2.21 g 3,5-dimethoxy-4-ethoxyphenylacetonitrile in 25 mL EtOH containing 2.5 mL concentrated HCl and 400 mg 10% palladium on charcoal, was shaken in a 50 lb/sq.in. atmosphere of hydrogen for 24 h. Celite was added to the reaction suspension and, following filtration, the solvents were removed under vacuum. The residue was recrystallized from IPA/Et2O to yield 2.14 g 3,5-dimethoxy-4-ethoxyphenethylamine hydrochloride (E) with a mp of 166-167 °C.
Synthesis from syringaldehyde: A well-stirred suspension of 21.9 g syringaldehyde in 45 mL H2O was heated to reflux in a heating mantle. There was then added a solution of 15 g NaOH in 60 mL H2O. The heating and stirring was continued until the generated solids redissolved. Over a period of 10 min, there was added 23 g diethyl sulfate, then refluxing was continued for 1 h. Four additional portions each of 5 g diethyl sulfate and of 6 mL 20% NaOH were alternately added to the boiling solution over the course of 2 h. The cooled reaction mixture was extracted with Et2O, the extracts pooled and dried over anhydrous MgSO4, decolorized with Norite, and stripped of solvent. The crude 3,5-dimethoxy-4-ethoxy-benzaldehyde weighed 21.8 g and melted at 51-52 °C.
A solution of 14.7 g 3,5-dimethoxy-4-ethoxybenzaldehyde and 7.2 mL nitromethane in 50 mL glacial acetic acid was treated with 4.4 g anhydrous am-monium acetate and held at reflux for 30 min. Cooling the reaction allowed the formation of yellow crystals which were removed by filtration and washed sparingly with cold acetic acid. The dried 3,5-dimethoxy-4-ethoxy-beta-nitrostyrene weighed 11.5 g and melted at 108-109 °C after recrystallization from EtOH Anal. (C12H15NO5) C,H. Alternately, this product may be prepared from 3.9 g. 3,5-dimethoxy-4-ethoxybenzaldehyde in 60 mL nitromethane containing 0.7 g ammonium acetate and heated on a steam bath for 1 h. The solvent was removed under vacuum, and the residue dissolved in a minimum of hot MeOH. Cooling provided, after filtration and air drying, 2.3 g of bright yellow crystals of 3,5-dimethoxy-4-ethoxy-beta-nitrostyrene, with a mp of 105-107 °C.
A solution of 2.25 g LAH in 45 mL anhydrous THF was vigorously stirred and cooled to 0 °C under He. There was added 1.5 mL 100% H2SO4 dropwise, followed by 2.3 g 3,5-dimethoxy-4-ethoxy-beta-nitrostyrene in anhydrous THF. After the addition was complete, the mixture was allowed to stir for 30 min, and then brought to room temperature. The unreacted hydride was decomposed with 2.3 mL H2O in THF, followed by the addition of 9.2 mL of 15% NaOH. The white suspension was filtered, the filter cake was washed with THF, the filtrate and washings combined, and the solvent removed under vacuum. The residue was dissolved in 300 mL dilute H2SO4, washed with 2x75 mL CH2Cl2, made basic with 25% NaOH, and the product extracted with 3x75 mL CH2Cl2. After removal of the solvent, the residue was distilled at 110-120 °C at 0.3 mm/Hg yielding 1.4 g of a colorless oil. A solution of this oil in 20 mL IPA was neutralized with 17 drops of concentrated HCl and diluted with 100 mL anhydrous Et2O. After a few minutes there was the spontaneous formation of white crystals of 3,5-dimethoxy-4-ethoxyphenethylamine hydrochloride (E) which was recrystallized from 40 mL boiling EtOAc containing 1 mL MeOH. The mp was 165-166 °C.