Crystal carboxylic acids

Methyl Red (4-dimethylaminoazobenzene-2 -carboxylic acid) [493-52-7] M 269.3, m 181-182 , Cl 13020, pK j 2.30, pK2 4.82. The acid is extracted with boiling toluene using a Soxhlel apparatus. The crystals which separated on slow cooling to room temperature are filtered off, washed with a little toluene and recrysld from glacial acetic acid, benzene or toluene followed by pyridine/waler. Alternatively, dissolved in aq 5% NaHC03 soln, and ppted from hot soln by dropwise addition of aq HCl. Repealed until the extinction coefficients did not increase. 

Ferrocene carboxylic acid [1271-42-7] M 230.1, m 210°(dec), 225-230°(dec). Yellow crystals from pet ether. Also crystd from aqueous ethanol. [Matsue et al. J Am Chem Soc 107 3411 1985.] Acid chloride m 49° crystallises from pentane, Xmax 458nm [J Org Chem 24 280 1959], Methyl ester crystallises from aq MeOH m 70-71°. Anhydride m 143-145° from pet ether [J Org Chem 24 1487 7959]. Amide m 168-170° from CHCl3-Et20 or m 167-169° from C6H6-MeOH. [J Am Chem Soc 77 6295 1955 76 4025 7954.]... 

Fusaric acid (5-n-butylpyridine-2-carboxylic acid) [536-69-6] M 179.2, m 96-98°, 98°, 98-100°, 101-103°, pK] 5.7, pK2 6.16 (80% aq methoxyethanol). Dissolve in CHCI3, dry (Na2S04), filter, evaporate and recrystallise the residue from 50 parts of pet ether (b 40-60°) or EtOAc, then sublime in vacuo. The copper salt forms bluish violet crystals from H2O and has m 258-259°. [Hardegger and Nikles Helv Chim Acta 39 505 1956 Schreiber and Adam Chem Ber 93 1848 1960 NMR and MS Tschesche and Fuhrer Chem Ber 111 3500 1978.]... 

The NMR spectrum of this compound shows a diamagnetic ring current of the type expected in an aromatic system. X-ray crystal structures of 1 and its carboxylic acid derivative 2 are shown in Fig. 9.2. Both reveal a pattern of bond lengths very similar to that in naphthalene (see p. 534). ... 

Fig. 9.2. X-ray crystal stmctures of l,6-methanodeca-l,3,5,7,9-pentaene (A) and 1,6-methanodeca-l,3,5,7,9-pentaene-2-carboxylic acid (B). (Structures are reproduced from Refs. 41 and 42 by permission of the International Union of Crystallography and Verlag Helvetica Chimica Acta AG.)...

Fig. 9.4. (A) X-ray crystal structure of j> n-tricyclo[8.4.1.F ]hexadeca-2,4,6,8,10,12,14-heptaene. iB) X-ray crystal structure of anti stereoisomer of tricyclo[8.4.1.1 ]hexadeca-2,4,6,8,10,12,14-heptaene-5-carboxylic acid. (Reproduced from Ref 63 by permission of Wiley-VCH.)...

Bond-Huper [69JCS(C)2453] synthesis, no traces of the described high-melting dark red substance were found. Only tolane-2-carboxylic acid amide (yield 65%) was obtained—the white crystals with a melting temperature of 156-157°C— which coincided with the results of Castro et al. (66JOC4071). Thus, in conditions of acetylide synthesis, o-iodobenzamide forms no bicyclic product. 

The X-ray crystal analysis of 5-trimethylsilanyl-4-trimethylsilanylethynyl-l//-pyrazole-3-carboxylic acid ethyl ester was obtained only with / = 0.17 because the crystals of the molecule diffracted extremely weakly and only a very limited data set was available. This means that although the gross stereochemistry of the molecule has been determined, individual bond lengths are not reliable (88JOM247). 

The solid state structure of (3>S,8 Sj-10-(8-amino-6-azaspiro[3,4]octan-6-yl)-9-fluoro-3-methyl-7-oxo-2,3-dihydro-7//-pyrido[l,2,3-dfe]-l,4-benzoxa-zine-6-carboxylic acid (218) was determined by X-ray diffraction study (98CPB1710). The structure of 6,10-dihydropyrido[2,l-c][l,4]benzoxazine-6,10-dione 219 was established by X-ray diffraction analysis. It contains a crystal solvate with /j-xylene (99MI40). 

Free radical additions to mono-olefins are quite common and can frequently be employed to advantage on a synthetic scale. Formamide, for example, on exposure to sunlight or UV radiation adds to olefins in an anti-Markovnikov sense giving 1 1 adducts that are readily isolated and crystallized. Moreover, since alkyl formamides may be conveniently converted to carboxylic acids by conventional means, the reaction represents a general method of chain extension. 

A suspension of 37.3 g (0.1 mol) of 7/3-amino-3-methoxy-3-cephem-4-carboxylic acid hydrochloride dioxanate in 500 ml methylene chloride is stirred for 15 minutes at room temperature under an argon atmosphere and treated with 57.2 ml (0.23 mol) of bis-(trimethylsilyl)-acetamide. After 45 minutes the faintly yellow slightly turbid solution is cooled to 0°C and treated within 10 minutes with 31.2 g (0.15 mol) of D-Ct-amino-Ct-d, 4-cyclohexadienyl (acetyl chloride hydrochloride. Thirty minutes thereafter 15 ml (about 0.21 mol) of propylene oxide is added and the mixture is further stirred for 1 hour at 0°C. A cooled mixture of 20 ml of absolute methanol in 200 ml of methylene chloride is added within 30 minutes, after another 30 minutes the precipitate is filtered off under exclusion of moisture, washed with methylene chloride and dried under reduced pressure at room temperature. The obtained hygroscopic crystals of the hydrochloride of 7j3-[D-a-(1,4-cyclohexadienyl)acetylamino] -... 

To a suspension of 12.0 grams of 3-methylflavone-8-carboxylic acid in 200 ml of anhydrous benzene Is added 10.0 grams of thionyl chloride. The mixture is refluxed for 2 hours during which the suspended solid goes into solution. The solvent is completely removed by distillation, the residue extracted with benzene and the extract evaporated to dryness. The product, 3-methylflavone-8-carboxylic acid chloride, is recrystallized from ligroin to give crystals melting at 155° to 156°C. 

Methyl pyrazine-2-carboxylic acid is refluxed with thionyl chloride in anhydrous benzene for approximately 12 hours. Benzene and thionyl chloride excess is removed by distillation. Then some anhydrous dioxane is added and this acid chloride solution is allowed to drop into p-(/3-aminoethyl)-benzenesulfonamide suspension in dioxane and anhydrous pyridine. The resulting mixture is then refluxed for 3 hours. Dioxane is removed by distillation and then the residue is washed with water and acetic acid. The raw acylated sulfonamide is then filtered and crystallized from 95% ethanol, thus obtaining a product of MP 200 to 203 C. 

There is obtained from 4-[)3-[5-methyl-isoxazolyl-(3)-carboxamido]-ethyl]-benzene-sulfonamide (prepared from 5-methyl-isoxazole-(3)-carboxylic acid chloride and 4-()3-aminoethyl)-benzene-sulfonamide hydrochloride, MP 213° to 214°C in pyridine) and chloroformic acid methyl ester, in a yield of 69%, the compound N-[ [-4-[)3-[5-methyl-isoxazolyl-(3)-carbox-amido] -ethyl] ] -benzene-sulfonyl] ] -methyl-urethane in the form of colorless crystals of MP 173°C. 

Under a pressure of 4,5 ml the 1 methyl-4-phenyl-piperidine-4-carboxylic acid nitrile passes over at a temperature of about 148°C in the form of a colorless oil under a pressure of 6 ml it passes over at about 158°C. After having been allowed to cool the distillate solidifies completely to form a crystalline mass. Its solidification point is at 53°C the yield amounts to about 135 parts, that is, about % of the theoretical yield. When recrystallized from isopropyl alcohol the hydrochloride of the nitrile forms colorless crystals, readily soluble in water and melting at 221° to 222°C. 

The nitrile may best be saponified with methyl alcoholic potash while heating to 190° to 200°C with application of pressure. After the methyl alcohol has evaporated the salt is introduced into water and by the addition of dilute mineral acid until the alkaline reaction to phenolphthalein has just disappeared, the amphoteric 1-methyl-4-phenyl-piperidine-4-carbOxylic acid is precipitated while hot in the form of a colorless, coarsely crystalline powder. When dried On the water bath the acid still contains 1 mol of crystal water which is lost only at a raised temperature. The acid melts at 299°C. Reaction with ethanol yields the ester melting at 30°C and subsequent reaction with HCI gives the hydrochloride melting at 187° to 188°C. 

The suspension was heated to 90°C, while stirring. The crystals were separated and recrystallized from 2B0 cm of a mixture of DMF (1 volume) and ethanol (4 volumes). After drying in vacuo ovar phosphorus pentoxide, 29.5 g (yield 70%) of 1-ethyl-6-fluoro-4-oxo-7-pl-perazinyl-1,4-dihydroquinoline-3-carboxylic acid, melting point 222°C, were obtained. 

The organic layer wasdried with anhydrous magnesium sulfate and then filtered. The solution was concentrated under vacuum at 30°C to 35°C until reduced to half of its original volume and then cooled to 5°C to allow the crystallization of the compound. Thus, the cake was filtered, washed with cool ethyl acetate, and dried under vacuum. Yield 74% (76.7 g) of phthalidyl ester of 2-(3 -trifluoromethylanilino)-pyridin-3-carboxylic acid, melting point 165°C to 167°C. 

Cysteine is first dissolved in distilled water which has been freed of oxygen by boiling. Formaldehyde of 30% (w/v) concentration is added while stirring and the temperature of the mixture rises, while the thiazolidine carboxylic acid begins crystallizing. The stirring is continued for 2 hours after which ethyl alcohol of 95% (w/v) concentration Is added to induce further crystallization. The mixture is left to stand for 24 hours at 4°C. The mixture is then filtered with retention of a crude product, which is purified by recrystallization from boiling distilled water. The crystals are then dried at about 40°C. The free acid is then converted to the sodium salt with NaOH. 

Chromium, (ri6-benzene)tricarbonyl-stereochemistry nomenclature, 1,131 Chromium complexes, 3,699-948 acetylacetone complex formation, 2,386 exchange reactions, 2,380 amidines, 2,276 bridging ligands, 2,198 chelating ligands, 2,203 anionic oxo halides, 3,944 applications, 6,1014 azo dyes, 6,41 biological effects, 3,947 carbamic acid, 2,450 paddlewheel structure, 2, 451 carboxylic acids, 2,438 trinuclear, 2, 441 carcinogenicity, 3, 947 corroles, 2, 874 crystal structures, 3, 702 cyanides, 3, 703 1,4-diaza-1,3-butadiene, 2,209 1,3-diketones... 

D. 2(S)-(fl-tert-Butoxycarbonyl-a-(R)-hydroxyethyl)-4-(R)-hydroxy-pyrrolidine- 1-carboxylic acid, tert-butyl ester. The identical procedure was followed, in this case using the (,S)-BINAP catalyst (5)-l. Hydrogenation is conducted for 64 hr, and the reaction mixture is then transferred to a 250-mL, round-bottomed flask and concentrated to dryness. The residue is dissolved in 17 mL of methanol and cooled to 15°C. After the slow addition of 7 mL of DI water, the solution is aged for 15 min gradually forming a thin slurry. More DI water (75 mL) is added over 1 hr and the mixture is allowed to stand for an additional 1 hr at 15°C. The resulting crystals (Note 19) are filtered at 15°C, washed with 10 mL of 1 4-MeOH water, and then dried overnight in a vacuum oven (35°C, 686 mm) to yield 7.0 g (70%) of (R)-hydroxy ester 4b (Note 20). 

The photo-Kolbe reaction is the decarboxylation of carboxylic acids at tow voltage under irradiation at semiconductor anodes (TiO ), that are partially doped with metals, e.g. platinum [343, 344]. On semiconductor powders the dominant product is a hydrocarbon by substitution of the carboxylate group for hydrogen (Eq. 41), whereas on an n-TiOj single crystal in the oxidation of acetic acid the formation of ethane besides methane could be observed [345, 346]. Dependent on the kind of semiconductor, the adsorbed metal, and the pH of the solution the extent of alkyl coupling versus reduction to the hydrocarbon can be controlled to some extent [346]. The intermediacy of alkyl radicals has been demonstrated by ESR-spectroscopy [347], that of the alkyl anion by deuterium incorporation [344]. With vicinal diacids the mono- or bisdecarboxylation can be controlled by the light flux [348]. Adipic acid yielded butane [349] with levulinic acid the products of decarboxylation, methyl ethyl-... 

Speakman JC (1972) Acid Salts of Carboxylic Acids, Crystals with some Very Short Hydrogen Bonds. 12 141-199 Spirlet J-C, see Muller W (1985) 59/60 57-73... 

---