3,5-dimethoxy-4-phenylmethoxybenzaldehyde

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

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

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

Procedure: The starting material is prepared as follows: To the mixture of 31.5 g of carbon tetrabromide and 65 ml of methylene chloride the solution of 50.0 g of triphenylphosphine in 175 ml of methylene chloride is added dropwise while stirring at 0°-5° under nitrogen. After 20 minutes the solution of 13.5 g of 4-benzyloxy-3,5-dimethoxybenzaldehyde in 50 ml of methylene chloride is added dropwise and the mixture stirred at room temperature for 2 hours. It is washed with 200 ml of water, dried and evaporated. The residue is extracted with hexane-diethyl ether (5:1), the extract evaporated, the residue chromatographed on silica gel, eluted with diethyl ether, the eluate evaporated and the residue recrystallized from hexane, to yield the β,β-dibromo-4-benzyloxy-3,5-dimethoxy-styrene melting at 76°-77°. The starting material is prepared is added dropwise the mixture stirred at room temperature for 2 hours It is washed with 200 ml of water dried evaporated The residue is extracted with hexane-diethyl ether (5:1) the extract evaporated the residue chromatographed on silica gel eluted with diethyl ether the eluate evaporated the residue recrystallized from hexane

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

Procedure: The starting material is prepared as follows: To the mixture of 31.5 g of carbon tetrabromide and 65 ml of methylene chloride the solution of 50.0 g of triphenylphosphine in 175 ml of methylene chloride is added dropwise while stirring at 0°-5° under nitrogen. After 20 minutes the solution of 13.5 g of 4-benzyloxy-3,5-dimethoxybenzaldehyde in 50 ml of methylene chloride is added dropwise and the mixture stirred at room temperature for 2 hours. It is washed with 200 ml of water, dried and evaporated. The residue is extracted with hexane-diethyl ether (5:1), the extract evaporated, the residue chromatographed on silica gel, eluted with diethyl ether, the eluate evaporated and the residue recrystallized from hexane, to yield the β,β-dibromo-4-benzyloxy-3,5-dimethoxy-styrene melting at 76°-77°. The starting material is prepared is added dropwise the mixture stirred at room temperature for 2 hours It is washed with 200 ml of water dried evaporated The residue is extracted with hexane-diethyl ether (5:1) the extract evaporated the residue chromatographed on silica gel eluted with diethyl ether the eluate evaporated the residue recrystallized from hexane

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

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

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

Procedure: To a stirring suspension of syringaldehyde (25.19 g, 138 mmol) and potassium carbonate (38.14 g, 276 mmol, 2 equ) in N,N-dimethyl formamide (500 ml) was added benzyl bromide (20 ml, 168 mmol, 1.2 equ). The reaction was stirred for 25 hours, then poured into dichloromethane. The organic solvent was washed with water (5×) then dried (MgSO4) and concentrated in vacuo to give a pink oil. This was recrystallised from hexane to give 31 (32.9 g, 87 %). The organic solvent was washed with water (5×) then dried (MgSO4) concentrated in vacuo to give a pink oil This was recrystallised from hexane

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

Procedure: A mixture of syringaldehyde (3.64 g, 20 mmol), benzyl chloride (2.52 g 20 mmol), NaI (2 g) and potassium carbonate (2.76 g, 20 mmol) in anhydrous acetone (60 mL) were refluxed for 5 h and cooled to room temperature. The solid materials were removed by filtration, the filtrate was concentrated and the residue was purified by chromatography on silica gel (230-400 mesh, 50 g) using 5% EtOAc in hexane as the eluent to obtain 13j (4.3 g, 79%); mp 62°-63° C. were refluxed for 5 h The solid materials were removed by filtration the filtrate was concentrated the residue was purified by chromatography on silica gel (230-400 mesh, 50 g)

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

Procedure: 4-Benzyloxy-3,5-dimethoxybenzaldehyde (13j) was prepared by the reaction of syringaldehyde with benzyl chloride in the presence of K2CO3 in boiling acetone. Similarly, reaction of t-butyldimethylsilyl chloride with syringaldehyde in DMF in the presence of N,N-diisopropylethylamine gave 4-(t-butyldimethylsilyl)-oxy-3,5-dimethoxybenzaldehyde (13k) (Scheme VII). Wittig reaction of phosphonium bromides 14a-b with benzaldehydes 13a-k in THF in the presence of sodium hydride followed by preparative thin-layer chromatographic separation of the crude products afforded the cis stilbenes 15a-k and trans stilbenex 16a-k (Scheme VIII). Reaction of compounds 15k and 16k with tetra-n-butylammonium fluoride and in situ acetylation of the phenols with acetic anhydride gave the acetoxy compounds 15l and 16l (Scheme IX). The cis and trans geometries of the stilbenes were assigned by the characteristic 1H NMR coupling constants of the olefinic protons. Catalytic hydrogenation of stilbenes 15 and 16 at about 40 psi in the presence of 10% palladium on charcoal gave the dihydrostilbenes 17a-e (Scheme XIII). The amino ethers 17f-g were prepared by the reaction of 1-(4-hydroxyphenyl)-2-(3,4,5-trimethoxyphenyl)ethane (18) with dialkylaminoethyl chlorides 19a-b in refluxing acetone in the presence of K2CO 3 (Scheme X). Compounds 17h and 17i were prepared by the alkylation of 3,4,5-trimethoxyphenyl-acetonitrile (20a) and 4-methoxyphenylacetonitrile (20b) with 4-methoxybenzyl bromide (21a) and 3,4,5-trimethoxybenzyl bromide (21b), respectively, using LDA as the base (Scheme XI). Similarly, alkylation of methyl 4-methoxyphenylacetate (20b) with 3,4,5-trimethoxybenzyl bromide 21b gave product 17j.

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

Procedure: The starting material is prepared as follows: To the mixture of 31.5 g of carbon tetrabromide and 65 ml of methylene chloride the solution of 50.0 g of triphenylphosphine in 175 ml of methylene chloride is added dropwise while stirring at 0°-5° under nitrogen. After 20 minutes the solution of 13.5 g of 4-benzyloxy-3,5-dimethoxybenzaldehyde in 50 ml of methylene chloride is added dropwise and the mixture stirred at room temperature for 2 hours. It is washed with 200 ml of water, dried and evaporated. The residue is extracted with hexane-diethyl ether (5:1), the extract evaporated, the residue chromatographed on silica gel, eluted with diethyl ether, the eluate evaporated and the residue recrystallized from hexane, to yield the β,β-dibromo-4-benzyloxy-3,5-dimethoxy-styrene melting at 76°-77°. The starting material is prepared is added dropwise the mixture stirred at room temperature for 2 hours It is washed with 200 ml of water dried evaporated The residue is extracted with hexane-diethyl ether (5:1) the extract evaporated the residue chromatographed on silica gel eluted with diethyl ether the eluate evaporated the residue recrystallized from hexane