Cinnamate, 3,4,5-trimethoxy

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). 

Slotta and Heller (109, 110) prepared their starting material, viz., trimethoxyphenylpropionic acid by condensation of the substituted benzaldehyde with malonic acid and reduction of the resulting cinnamic acid. Mescaline was then obtained by Hofmann degradation of the trimethoxyphenlypropionamide. Kindler and Peschke (103) synthesized very pure, crystallized mescaline by condensation of 3 4 5-trimethoxy-benzaldehyde with potassium cyanide, acetylation, and catalytic reduction to the amine. Slotta and Szyska (111, 112) improved Spath s first synthesis, obtaining mescaline directly by the electrolytic reduction of w-nitrotrimethoxystyrene. Hahn and Wassmuth (113, 114) started from elemicine and first prepared trimethoxyphenylacetaldehyde by ozonization. The oxime was then reduced to mescaline. Kindler (115) and Kindler and Peschke (38, 103) improved the catalytic reduction of w-nitrostyrenes to the corresponding phenethylamines. Hahn and Rumpf (116) described the preparation of mescaline by reduction of w-nitrotrimethoxystyrene with Adam s catalyst. A review has been published by Jensch (117). 

Chromic anhydride-pyridine, 70 Chromium hexacarbonyl, 71 Chromones, 423 Chromous chloride, 73 Chrysanthemic acid, 49, 50, 207-208 Chrysanthemic esters, 183-184 Cinnamic esters, 362 CitroneUol, 5, 308, 309 Claisen rearrangement, 2, 372 Clemmensen reduction, 426 Cocaine, 384 Codeine, 236, 347, 348 Conjugate addition, 86, 102, 119-120, 133, 226-227, 253, 353, 400 Cope rearrangement, 66, 397 Copper, 73-74 Copper(I) acetate, 80 Copper(II) acetate, 39, 117, 126, 186 Copper(I) bromide-Lithium trimethoxy-aluminum hydride, 80 Copper(I) bromide, 79-80 Copper(I) chloride, 50, 80-81 Copper(II) chloride, 126, 79 Copper(l) cyanoacetate, 74 Copper halide nitrosyls, 73 CopperO) iodide, 81-82 Copper(I) methyltrialkylborates, 4,75 CopperGD perchlorate. 79 COpper(I) phenylacetylide, 237 Copper(II) sulfate, 117 CopperO) trifluoiomethanesulfonate, 75-76... 

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