Chakravarti, Duhkhaharan published the artcileSynthesis of coumarins from o-hydroxyaryl alkyl ketones. II. Formation of o-coumaric acids from o-hydroxyaldehydes, Formula: C11H12O4, the publication is Journal of the Indian Chemical Society (1939), 389-92, database is CAplus.
cf. C. A. 32, 7026.9; 33, 549.4. The Me ethers of the o-HO aldehydes condense with EtO2CCH2Br (I) and EtO2CCHBrMe (II) to form trans-cinnamic esters, which do not yield coumarins on heating with HI or on standing with cold H2SO4 as do the esters obtained from o-hydroxyaryl alkyl ketones. A mixture of 11 g. o-MeOC6H4CHO in 50 cc. anhydrous benzene, 6 g. Zn wool and 16 g. I was heated at 100¡ã for 2 h. and poured into ice-cold dilute H2SO4. The washed and dried benzene layer was evaporated down and distilled, yielding 11 g. of o-MeOC6H4CH(OH)CH2CO2Et, b10 150-4¡ã, which was converted by heating with 6 g. SOCl2 and 9 g. pyridine in ether into 10 g. Et 2-methoxy-trans-cinnamate, C12H14O3, b8 150¡ã, hydrolyzed to 2-methoxy-trans-cinnamic acid, m. 182¡ã, identical with a specimen prepared from o-coumaric acid by methylation with Me2SO4 and hydrolysis. Similarly, o-MeOC6H4CHO was converted by Reformatski¨«’s reaction with Zn and II to o-MeC6H4CH(OH)CHMeCO2Et, b4 155¡ã, transformed by SOCl2 in the presence of pyridine to Et 2-methoxy-¦Á-methyl-trans-cinnamate, C13H16O3, b4 150-5¡ã, hydrolyzed by alc. KOH to the corresponding acid, m. 102¡ã. Condensation of 2,4-(MeO)2C6H3CHO with I gave 2,4-(MeO)2C6H3CH(OH)CH2CO2Et, b8 180-4¡ã, dehydrated to the cinnamic ester, b8 180-4¡ã, hydrolyzed to 2,4-dimethoxy-trans-cinnamic acid, m. 184¡ã. To study the influence of a Ph substituent on the formation of trans-cinnamic esters, 8.5 g. of 5,2-Cl(MeO)C6H3CHO was condensed with 8.5 g. I to the propionate (8 g.) which, on dehydration with SOCl2, gave 6 g. of Et 2-methoxy-5-chloro-trans-cinnamate, C12H13ClO3, b6 170¡ã, hydrolyzed to the corresponding acid (III), m. 191¡ã. A sample of authentic III was prepared by treating 6-chlorocoumarin with HgO, methylating and hydrolyzing with alc. KOH. Thus it is shown that if there are no ¦Â-alkyl groups in the resulting cinnamic ester, the latter has the trans configuration. Otherwise the esters have the cis configuration and readily form coumarins. The 2-MeO aldehydes are useful starting materials for the preparation of o-coumaric acid derivatives in satisfactory yields. Condensation of 10 g. of 2,4-(MeO)2C6H3Ac (IV) with 9 g. II and distillation of the product yielded 8.5 g. of Et 2,4-dimethoxy-¦Á,¦Â-dimethyl-cinnamate (V), b6 180-2¡ã, converted by standing overnight in cold H2SO4 (d. 1.84) to 3,4-dimethyl-7-methoxycoumarin, m. 140¡ã. Heating V (1 g.) with 7 cc. HI (d. 1.7) at 140¡ã for 2 h. gave colorless needles of 3,4-dimethyl-7-hydroxycoumarin, m. 256¡ã, on recrystallization from alc. Similarly, condensation of 10 g. IV with I gave an unsaturated ester, b6 174¡ã, on vacuum distillation No ring closure was effected by heating with HI or on treatment with cold H2SO4. Hydrolysis gave the known 2,4-dimethoxy-¦Â-methylcinnamic acid, m. 145¡ã.
Journal of the Indian Chemical Society published new progress about 16909-09-4. 16909-09-4 belongs to catalysis-chemistry, auxiliary class Alkenyl,Carboxylic acid,Benzene,Ether, name is (E)-3-(2,4-Dimethoxyphenyl)acrylic acid, and the molecular formula is C11H12O4, Formula: C11H12O4.
Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia