2-methyl-4,5-dicarboxylic acid

The last-named reagent also cleaves o-dihydroxybenzenes (catechols) to give, in the presence of MeOH, the mono-methylated dicarboxylic acids... 

Hydrolysis of ethyl 4-methyl-2,5-thiazole dicarboxylate (9) or dicar-boxylic acid dichloride gives an excellent yield of 4-methyl-5 thiazole carboxylic acid (10) instead of the dicarboxylic acid (Scheme 6). This lability is a general Property of 2-thiazolecarboxylic acids. 

Write equations showing how 3 methyl 1 5 pentanediol could be prepared from a dicarboxylic acid or a diester I... 

G-20 Dicarboxylic Acids. These acids have been prepared from cyclohexanone via conversion to cyclohexanone peroxide foUowed by decomposition by ferrous ions in the presence of butadiene (84—87). Okamura Oil Mill (Japan) produces a series of commercial acids based on a modification of this reaction. For example, Okamura s modifications of the reaction results in the foUowing composition of the reaction product C-16 (Linear) 4—9%, C-16 (branched) 2—4%, C-20 (linear) 35—52%, and C-20 (branched) 30—40%. Unsaturated methyl esters are first formed that are hydrogenated and then hydrolyzed to obtain the mixed acids. Relatively pure fractions of C-16 and C-20, both linear and branched, are obtained after... 

Diaziridine, 3-methyl-electron diffraction, 7, 199 (74CC397) Diaziridine-3,3-dicarboxylic acid, diethyl ester ESR, 7, 202 (76TU205)... 

Imidazole-4,5-dicarboxylic acid, 2-methyl-pK, 5, 384 [Pg.29]

Aziridine, 2,3-diphenyl-l-(2,4,6-trinitrophenyl)-irradiation, 7, 61 Aziridine, 1,2-divinyl-rearrangement, 7, 539 Aziridine, 2,3-divinyl-rearrangement, 7, 42, 65, 539 Aziridine, N-ethyl-inversion, 7, 6 Aziridine, 2-halo-reactions, 7, 74 Aziridine, A/-halo-invertomers, 7, 6 Aziridine, 2-methyl- N NMR, 7, 11 Aziridine, methylene-ring-ring valence isomerizations, 7, 22 synthesis, 7, 92 Aziridine, iV-nitroso-reactions, 7, 74 Aziridine, iV-phosphino-inversion, 7, 7 Aziridine, 1-phthalimido-UV irradiation, 7, 62-63 Aziridine, l-(3-thienyl)-2-vinyl-rearrangement, 4, 746 Aziridine, 7V-trimethylsilyl-inversion, 7, 7 Aziridine, 1,2,3-triphenyl-irradiation, 7, 61 Aziridine, vinyl-isomerization, S, 287 Aziridinecarboxylic acid ring expansion, 7, 262 Aziridine-2,2-dicarboxylic acid, 1-methoxy-diethyl ester... 

Chroman-6-carboxylic acid, 8-hydroxy-2-methyl-4-0X0—see Rosellinic acid, 718 Chroman-2,7-dicarboxylic acid, 2,4,4-trimethyl-formation, 3, 733... 

Imidazole-4,5-dicarboxylic acid, 1-methyl-decarboxylation, 5, 435 Imidazole-4,5-dicarboxylic acid anhydride synthesis, 5, 435... 

Isoxazoline-3,5-dicarboxylic acid, 4-oxo-diethyl ester synthesis, 6, 106 Isoxazoline-4,5-dione, 3-methyl-4-oxime... 

Oxepin, 4-ethoxycarbonyl-2,3,6,7-tetrahydro-synthesis, 7, 578 Oxepin, 2-methyl-enthalpy of isomerization, 7, 555 Oxepin, 2,3,4,5-tetrahydro-reduction, 7, 563 synthesis, 7, 578 Oxepin, 2,3,4,7-tetrahydro-synthesis, 7, 578 Oxepin, 2,3,6,7-tetrahydro-oxidation, 7, 563 reduction, 7, 563 Oxepin-2,6-dicarboxylic acid stability, 7, 565 Oxepinium ions synthesis, 7, 559 Oxepins, 7, 547-592 antiaromaticity, 4, 535 applications, 7, 590-591 aromatization, 7, 566 bond lengths and angles, 7, 550, 551 cycloaddition reactions, 7, 27, 569 deoxygenation, 7, 570 dipole moment, 7, 553 disubstituted synthesis, 7, 584... 

Pterin-6-cafboxylic acid, 3,8-dimethyl-rearrangements, 3, 309 Pterincarboxylic acids occurence, 3, 323 Pterin-6-carboxylic acids acidity, 3, 277 methylation, 3, 297 synthesis, 3, 295, 304 Pterin-7-carboxylic acids acidity, 3, 277 methylation, 3, 297 synthesis, 3, 295 Pterin coenzymes biochemical pathways, 1, 260-263 Pterin-6,7-dicarboxylic acid decarboxylation, 3, 304 reactions, 3, 304... 

Pyrimidine-4,5-dicarbonitrile, 2-methyl-faydrolysis, 3, 83, 84 Pyrimidine-4,5-dicarboxylic acid synthesis, 3, 76, 122 Pyrimidine-4,6-dicarboxylic acid decarboxylation, 3, 80... 

Pyrrole-2,3-dialdehyde, 1-methyl-pyrrolopyridazine synthesis from, 4, 517 Pyrrole-2,5-dicarboxylic acid, 3,4-dihydroxy-l-phenyl-diethyl ester... 

Pyrrole-3,5-dicarboxylic acid, 2-dichloromethyl-4-methyl-diethyl ester... 

Amino-4,6-dimethyl-3-oxo-3//-phenoxazine-l,9-dicarboxylic acid also named actinocin is the chromophor of the red antineoplastic chromopeptide aetinomyein D (formula A). Two cyclopenta-peptide lactone rings (amino acids L-threonine, D-valine, L-proline, sarcosine, and 7V-methyl-L-valine) are attached to the carboxy carbons of actinocin by two amide bonds involving the amino groups of threonine. 

FIGURE 24.27 Dicarboxylic acids can be formed by oxidation of the methyl group of fatty acids in a cytochrome P-450-dependent reaction. 

Diazopropyne reacts similarly with a monosubstituted acetylene to form 3(5)-alkynylpyrazoles (68LA113). Thus, the reaction of diazopropyne with acetylene-carboxylic acid methyl ether results in 5-ethynyl-l//-pyrazole-3-carboxylic acid methyl ether in 48 h in 62% yield. 5-Ethynyl-l//-pyrazole-3,4-dicarboxylic acid dimethyl ester was prepared by reaction of diazopropyne with acetylenedicar-boxylic acid methyl ether (Scheme 10). 

Pyridine 210 is oxidized by 20% nitric acid at the acetyl group to 2-methyl-5-pyridinecarboxylic acid, while its ozonation gives cinchomeronic acid [pyridine-2,5-dicarboxylic acid (215)] (75DIS) which is decarboxylated (200°C, 2 h) to nicotinic acid 216 in 97% yield (75DIS). 

Acidic hydrolysis of 2,3-dihydro-l//,7//-pyrido[3,2,1-//]cinnoline-3,3,8-tricarboxylate 57 with a mixture of 6N HCl and AcOH at 100 °C yielded 4,5-difluoro-1 -methyl-7-oxo-2,3-dihydro-1 //,7//-pyrido[3,2,1 -//]cinnoline-3,8-dicarboxylic acid (96BCJ1371). 

A mixture of 4.98 g of acetoacetic acid N-benzyl-N-methylaminoethyl ester, 2.3 g of aminocrotonic acid methyl ester, and 3 g of m-nitrobenzaldehyde was stirred for 6 hours at 100°C in an oil bath. The reaction mixture was subjected to a silica gel column chromatography (diameter 4 cm and height 25 cm) and then eluted with a 20 1 mixture of chloroform and acetone. The effluent containing the subject product was concentrated and checked by thin layer chromatography. The powdery product thus obtained was dissolved in acetone and after adjusting the solution with an ethanol solution saturated with hydrogen chloride to pH 1 -2, the solution was concentrated to provide 2 g of 2,6-dimethyl-4-(3 -nitrophenyl)-1,4-dihydropyridlne-3,5-dicarboxylic acid 3-methylester-5- -(N-benzyl-N-methylamino)ethyl ester hydrochloride. The product thus obtained was then crystallized from an acetone mixture, melting point 136°Cto 140°C (decomposed). 

An acetyl group in the 2-position favors the monocyclic structure presumably because of the resonance stabilization.12 The same observation was made with oxepin-2,7-dicarbaldehyde, oxepin-2,7-dicarboxylic acid, and oxepin-2,7-dicarbonitrile.23 Substituents in the 4- and 5-positions of the oxepin such as methyl or methoxycarbonyl groups shift the equilibrium towards the epoxide.12 24 Low temperature 1H NMR studies on 7-ethyloxepin-2-carbonitrile and ethyl 7-ethyloxepin-2-carboxylate established a nonplanar boat geometry with a ring-inversion harrier of 6.5 kcal mol-1.25... 

The first synthesis of a 3//-3-benzazepine, e.g. 65 (R1 = R2 = Me), was achieved by the condensation of phthalaldehyde with a bis[(alkoxycarbonyl)methyl]methylamine.24"25 With sodium methoxide as the base, A%V-bis[(methoxycarbonyl)methyl]pheiiylaniine condenses with the dialdehyde in a similar manner to give dimethyl 3-phenyl-3//-3-benzazepine-2,4-dicar-boxy late (65, Rl — Ph R2 — Me).99 However, replacement of methoxide by potassium tert-butoxide results in formation of 3-phenyl-3//-3-benzazepine-2,4-dicarboxylic acid (65, R1 = Ph R2 = H).25... 

Catalytic hydrogenation of dimethyl 3-methyl-3//-3-benzazepine-2,4-dicarboxylate (10) to the 1,2,4,5-tetrahydro derivative with hydrogen and a palladium-barium sulfate catalyst, followed by treatment of the reaction mixture with iodomethane in refluxing methanol, yields a mixture of the 2,4-dicarboxylic acid 11 and the methiodide salt 12.24... 

The formation of porphyrins from 1,19-dideoxybi)enes-/r can be achieved starting either from the 1-methyl derivatives or from l,19-dideoxybilene-Z>-l,19-dicarboxylic acid esters. In the first case the desired methine bridge of the porphyrin stems from the 1-methyl group whereas in the latter case orthoformates have to be added in the condensation step as a precursor for the methine unit. The 1-methyl- and also 1,19-dimethyl-l,19-dideoxybilene- > salts can be cy-clized to the corresponding porphyrins with copper(II) acetate in methanol.56 However, when the bilenes contain /i-acceptor substituents, the yields of porphyrins obtained by this method are very low.57... 

Methyl esters of short-chain dicarboxylic acids Loss of — OCH2CH2NH2 -C6H10(CO2CH3)2 O-methyl toluates... 

METHYL CHRYSANTHEMATE DIMETHYL PYRETHRATE mixture contribute to the total monocarboxylic and dicarboxylic acids found. 

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