2-Methyl-3-nitrocinnamic acid

The preparation of 2-methyl-3-nitrocinnamic acid is representative of the reaction and its conditions. 

Nitrobenzaldehyde has been prepared from />-nitrotoluene by treatment with isoamyl nitrite in the presence of sodium methylate,1 by oxidation with chromyl chloride,2 cerium dioxide,3 or chromium trioxide in the presence of acetic anhydride.4 It can also be prepared by the oxidation of -nitrobenzyl chloride,5 7>-nitrobenzyl alcohol,6 or the esters of -nitrocinnamic acid.7... 

Perfluoro(3-isothiocyanato-2-methyl-2-pentene) reacts with N-nucleophiles to produce a series of fluoroalkyl-substituted 6/f-l,3-thiazines <1997RJO720>. The acid-catalyzed cyclization of thioureas immobilized on Wang (X = O) or Rink resin (X = NH) provides a convenient route to a wide range of 2-amino-4/7-benzothiazine derivatives 212 (Scheme 23) <20000L3667>. The thioureas are obtained in four steps from 2-nitrocinnamic acids. A general synthesis of 2-alkylidene-4-imino-l,4-dihydrobenzo-l,3-thiazines 213-215 involves treatment of 2-isothiocyanato-benzonitrile with acidic methylene compounds under basic conditions <2003SL1503>. The ( )-isomers are the predominant isomers formed. 

C9H7N04 p-nitrocinnamic acid, predominantly trans 619-89-6 25.00 1.3674 2 16228 C9H803 methyl 4-formylbenzoate 1571-08-0 25.00 1.2467 2... 

Copp - powder. Use of commercial copper powder as a decarboxylation catalyst in quinoline solution is illustrated by the decarboxylation of 3-methyl-2-furoic acid and of /n-nitrocinnamic acid.°... 

Decarboxylation Reactions. Taking advantage of its basic properties, quinoline is generally useful as a solvent for decarboxylation reactions. It is especially suitable because its relatively high boiling point facilitates the decarboxylation. Examples include the decarboxylation of 3-methyl-2-furoic acid (10) to 3-methylfuran (11) (eq 6), /w-nitrocinnamic acid (12) to m-nitrost)frene (13) (eq and a-phenylcinnamic acid (14) to cis-stilbene (15) (eq 8). Copper catalysts such as copper or copper chromite are used to effect the decarboxylations. 

Olefinic esters may be obtained directly by the Knoevenagel reaction. Alkyl hydrogen malonates are used in place of malonic acid. Decarboxylation then gives the ester directly as in the preparation of ethyl 2-heptenoate (78%) and methyl m-nitrocinnamate (87%). Alkyl hydrogen malonates are readily available by partial hydrolysis of dialkyl malonates. The use of malonic ester in the condensation leads to olefinic diesters, namely, alkylidenemalonates such as ethyl heptylidenemalonate (68%). A small amount of organic acid is added to the amine catalyst since the salts rather than the free amines have been shown to be the catalysts in condensations of this type. Various catalysts have been studied in the preparation of diethyl methylenemalonate. Increased yields are obtained in the presence of copper salts. Trimethylacetalde-hyde and malonic ester are condensed by acetic anhydride and zinc chloride. Acetic anhydride is also used for the condensation of furfural and malonic ester to furfurylidenemalonic ester (82%). ... 

---