Cinnamic 2,3-dimethoxy

For PMMA/additive dissolutions, it was not possible to identify any additive characteristic mass peaks, either by direct laser desorption or with matrix-assistance (dithranol, DHBA or sinapinic acid, 4-hydroxy-3,5-dimethoxy-cinnamic acid). This has again been ascribed to very strong interaction between PMMA and additives, which suppresses desorption of additive molecules. Also, partial depolymerisation of pho-tolytically labile PMMA by laser irradiation may play a role, which leads to saturation of the detector by PMMA fragment-ions and disappearance of additive mass peaks below noise level. Meyer-Dulheuer [55] has also reported MALDI-TOFMS analysis of a coating/2-ethylhexyldiphenylphosphate sample. Quantitative determination of the additives by means of MALDI-ToFMS proved impossible. Possibly the development of reproducible (automated) sample handling procedures or thin films might overcome this problem. 

Cinnamate salts and cinnamic amides react with low regioselectivity to yield mixtures of the 2- and 3-alkylated products . orflzo-Substituted aryllithium-(-)-sparteine complexes 468 add with good enantiofacial discrimination to orf/zo-substituted ferf-butyl cinnamates 467 to give 469 (equation 128) ". The ehiral additive (i ,i )-l,2-dimethoxy-1,2-diphenylethane in some cases gave improved ee values. 

The synthesis of acrylic acid or its ester (228) from ethylene has been investigated in AcOH from the standpoint of its practical production 12]. The carbonylation of styrene is a promising commercial process for cinnamate (229) production[207,213,214]. Asymmetric carbonylation of styrene with Pd(acac)2 and benzoquinone in the presence of TsOH using 2,2 -dimethoxy-6, 6 -bis(diphenylphosphino)biphenyl (231) as a chiral ligand gave dimethyl phenylsuccinate 230 in 93% ee, although the yield was not satisfactory, showing that phosphine coordination influences the stereochemical course of the oxidative carbonylation with Pd(II) salt[215]. 

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]. 

Cinnamic Ethyl butyrate Ethanol n-Butanal 1,1 -Dimethoxy ethane... 

Thermal decomposition of 7,7-dialkoxynorbornadiene derivatives in the presence of an alkene requires rather high temperatures ( 125°C) l,2,3,4-tetrachloro-7,7-dimethoxy-5-phenylbicyclo[2.2.1 ]hepta-2,5-diene is the most often applied source of dimethoxycarbene. Electrophilic alkenes such as )- and (Z)-but-2-enedioates and cinnamates, styrene derivatives, " 1-phenylbuta-l,3-diene etc. undergo addition of this carbene across the double bond to give 1,1-dimethoxycyclopropanes 2. 

Unsaturated Lignin Model Compounds Double bonds in lignin model compounds are attacked by peracetate ions. Dehydro-di-woeugenol (XXI, Figure 12.9) reacted with epoxidation of the aliphatic double bond and formation of the diol. The double bonds in stilbenes [59] and coniferaldehyde [90] are also cleaved. FemUc acid (IVa) and its ethyl ester reacted slowly at 50°C the methyl ether, 3,4-dimethoxy cinnamic acid, was much less reactive and was almost quantitatively recovered [55]. The reactions of ferulic acid and its ethyl ester (both in the trans form) were accompanied by trans-cis isomerization, perhaps an indication of reversible phenoxy radical formation. HomovanilUc acid (XXXa) was also formed the proposed mechanism involved epoxidation of the a-P double bonds followed by decarboxylation. 

A cyclization of a dimethoxy cinnamic acid to a coumarin derivative is presented by... 

Cinnamic acid, 3,5-dimethoxy- sinapic acid 52. Phenol, 5-methyl-2-(l-methylethyl)- thymol... 

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