4-Methoxy cinnamic acid

DMA in 500 ml ether mix rapidly with 270 ml 0.9 M phenyl-Li, boil fifteen hours and extract as for (VI) or as described previously to get 8 g oily 4-methoxy-indoline (or its 1-methyl derivative) (VII). Alternatively, add 36 g naphthalene to 300 ml tetrahydrofuran and add 11 g Na metal cut in small pieces. Reflux and stir three hours and add 18 g (VI) and 8 g DEA in 200 ml tetrahydrofuran rapidly and boil twelve hours. Evaporate in vacuum, dissolve the oily residue in 2N HCI and extract with ether. Proceed as described to get (VII). 4 g (VII) in 200 ml dry pyridine add to 6 g Cu chloride in 400 ml pyridine and reflux 1 xh hours. Pour on water and extract with ether. Wash extract with 4N HCI and then water and dry and evaporate in vacuum the ether to get 2 g of the indole (VIII). Alternatively, dissolve 4 g (VII) and 9.5 g cinnamic acid in 700 ml mesitylene, add 1 g 5% palladium-carbon and reflux five hours. Filter, wash with HCI and NaHC03 and dry and evaporate in vacuum the mesitylene to get the red, oily (VIII) (can chromatograph on alumina and elute with benzene-petroleum ether). 

The sensitivity to temperature is reminiscent of that seen in Ron s study (188) of o-methoxy-m-cinnamic acid, 129. When crystals of this substance are exposed to light at low temperatures (< — 80°C), there occurs a gradual isomerization of the molecules to the trans form, 130, with formation of a little of the (2 + 2) photodimer, 131, of the latter. If this irradiated material is warmed in the dark to + 60°C, recooled, and reirradiated for a short while, there is a jump in the amount of dimer. This behavior is interpreted as follows ... 

Ferulic acid 4-Hydroxy-3-methoxy-cinnamic acid... 

The most common cinnamic acids are caffeic (3,4-dihydroxycinnamic acid), ferulic (3-methoxy-4-hydroxy), sinapic (3,5-dimethoxy-4-hydroxy) and p-coumaric (4-hydroxy) acid, Table 4 [13]. 

Compound retention during RP-HPLC depends on the relative hydrophobicity of the sample compounds. As expected, the elution of phenolics for reversed-phase HPLC is in the order of decreasing polarity. Polarity is increased most by hydroxyls at the 4-position, followed by those at the 2- and 3-positions. Availability of the methoxy group and the acrylic substitution reduces polarity and increases retention times (4). Loss of polar hydroxy groups and/or addition of methoxy groups can decrease the polarity within each class of benzoic and cinnamic acid. Also, the presence of the ethylenic side chain in the cinnamic acids can reduce their polarity compared with similarly substituted benzoic acids (6). The elution order for benzoic acids is as follows (Table 1) gallic > a-resorcylic > protocatechuic > y-resorcylic > gentisic > p-hydroxyben-... 

Bromination of cinnamic acid with NBS in aq. MeOH gives 2-bromo-3-methoxy-3-phenyl propionic acid, PhCH(0Me)CHBrC02H. At moderately high [H+] the reaction is second-order and independent of [H+], whereas at low [H+] the rate increases with decrease in [H+], Succinimide inhibits the reaction182. 

Scheme 2 shows Rapoport s synthesis [15]. The cinnamic acid derivative 3 prepared from m-methoxy benzaldehyde [20] was ethylated by diethyl sulfate to give ethyl cinnamate derivative 4, followed by Michael addition with ethyl cyanoacetate to afford compound 5. Compound 5 was converted to lactam 6 by the reduction of the cyano group and subsequent cyclization. Selective reduction of the lactam moiety of 6 was achieved by treatment with trimethy-loxonium fluorob orate followed by sodium borohydride reduction. Amine 8 was obtained by the reductive methylation of amine 7. Amine 8 was converted to compound 9 by methylene lactam rearrangement [21], followed by selenium dioxide oxidation to provide compound 10. Allylic rearrangement of compound 10 and subsequent hydrolysis gave compound 12. The construction of the decahydroisoquinoline structure began with compound 12,... 

A similar sequence probably accounts for the formation of 50% (40%) 1-clilo-ro- (1-bromo-) -2-methoxy-2-phenylpropionic acid by electrolysis of cinnamic acid in CH30H/NH4C1 (NH4Br)as SSE 271 Electrolysis of irans-stilbene in me-thanol/NH4Br produces eryr ro-stilbene dibromide and l-methoxy-2-bromo-1,2-diphenylethane 1 °4-1 in fair yields. 

Khopade SM, Priyadarshini Kl, Guha SN, Mukherjee T. (2001) Hydroxyl radical induced oxidation of 4-hydroxy 3-methoxy cinnamic acid (ferulic acid). Rjes Chem Intermed 27 519-527. 

Cinnamic acids can be created from the methylation of coumarins. Methoxy substituted coumarins produce lower yields than do non-substituted and hydroxy substituted coumarins. 

Photosensitized crosslinking of polymers has been the subject of numerous publications [l - 30], concerned mainly with poly(ethylene), poly(vinyl alcohol), various vinyl copolymers, copolymers of maleic anhydride and/or phtalic anhydride with styrene and some polymers derivated from cinnamic acid. The following compounds were used as sensitizers benzophenone, 4-chloro- and 4,4-dimethylbenzophenone [l, 3-6, 8, 9l, oC -and -derivatives of anthraquinone [3, 23] acetophenone, hydroquinone, triphenylmethane and pyridine li.] chlorobenzene and no less than trichlorinated n-paraffins [6], a complex of zink chloride with o-dia-nizidine fill potassium bichromate [l2j, anthracene fl3, 14] 2,5-methoxy-4-amino-trans-stilbene [l5], benzyl ideneacetophenone fl6-l8] -thiophenylacetophenone,... 

A different approach consists of a two-steps stereoselective synthesis of Combretastatin A-4, based on the Perkin condensation of 3,4,5-trimethoxy phenyl acetic acid and 3-hydroxy-4-methoxy benzaldehyde, followed by decarboxylation of the cinnamic acid intermediate using copper and quinoline [11] (Schema 4). 

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