3,4-Diaminobenzoic acid

SCHEME 44. 3,5-Diaminobenzoic acid scaffolds prepared using Sonogashira chemistry.3... 

Diaminobenzoic acid (DABA) reacts with aldehydes of the form RCH CHO to produce a strongly fluorescent compound. Acid-catalysed removal of the purine base from the nucleic acid exposes the 1 and 2 carbons of deoxyribose... 

Kim reported on liquid crystalline properties observed for hyperbranched aromatic amides obtained from 3,5-diaminobenzoic acid and derivatives thereof. The resulting polymers exhibited nematic liquid crystalline phases [89]. 

Kricheldorf et al. have investigated several hyperbranched poly(ester-amide)s derived from combinations of 3,5-diaminobenzoic acids and 3,5-dihydroxy-benzoic acids and similar monomers [100-102]. The polymers exhibited values of Tg ranging from 160 to 250 °C and were highly soluble in various solvents. They employed diamines as star centers in order to control the molecular weight. 

Zeolite/polymer mixed-matrix membranes prepared from crosslinked polymers and surface-modified zeolite particles offered both outstanding separation properties and swelling resistance for some gas and vapor separations such as purification of natural gas. Hillock and coworkers reported that crosslinked mixed-matrix membranes prepared from modified SSZ-13 zeolite and 1,3-propane diol crosslinked polyimide (6FDA-DAM-DABA) synthesized from 2,2 -feis-(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, p-dimethylaminobenzylamine-and 3,5-diaminobenzoic acid displayed high CO2/CH4 selectivities of up to 47 Barrer and CO2 permeabilities of up to 89 Barrer under mixed gas testing conditions [71]. Additionally, these crosslinked mixed-matrix membranes were resistant to CO2 plasticization up to 450 psia (3100kPa). 

It is interesting to note that the AB-monomer, 3,4-diaminobenzoic acid is an exception, and higher molecular weights are obtained from dilute polycondensations in PPA. 

Only aldehydes with an a-methylene group (i, e., R—CH2CHO) condense with 3,5-diaminobenzoic acid to form quinaldines.92 Consequently, in the carbohydrate series only 2-desoxysugars will react. The usual procedure adopted is to add to the unknown sugar solution an equal volume of a 1.3 percent solution of 3,5-diaminobenzoic acid hydrochloride in 50 percent aqueous perchloric acid. If the carbohydrate solution contains a 2-desoxysugar it will assume a yellow color with a green fluorescence.93 Use of an ester instead of a salt of 3,5-diaminobenzoic acid reduces the sensitivity of the test. 

Quinaldine A 1 to 1.5% solution of 3,5-diaminobenzoic acid dihydrochloride in 30% phosphoric acid is sprayed on the plate, which is then heated (100°C, 15 min) to yield fluorescent (green/yellow) spots under long-wave UV or (in case of high concentrations) brown spots in daylight. 

Detailed analysis using several different methods (Pulse and continuous label with tritiated thymidine, DNA fluorescence per cell using the fluorescent Feulgen assay and flow microfluorography (Van Dilla et al., 1969), and DNA specific fluorescence using the diaminobenzoic acid assay (Kissane and Robins, 1958) reveals that the DNA content of a cell increases in a saltatory fashion, and that the early portion of S-phase is a period of low net DNA synthesis which may be mistaken for G1 if insensitive methods of measurement are used (Klevecz et al., 1975). 

The diphenylamine method can be scaled down to increase sensitivity and fluorescent methods are available using diaminobenzoic acid, diamidino-phenylindole (DAP1), ethidium bromide or propidium iodide (Kissane and Robins, 1958 Hinegardner, 1971 Klotz and Zimm, 1972) which are sensitive down to 0.1 fig DNA. 

Other diamines, such as 2,3-diamino-4(3H)-quinazolone and 2,3-diaminobenzoic acid, behave similarly to o/V/zo-phenylenediamine when reacted with isatin. 

C7H7N03 2-hydroxy-6-methy pyridine-3-carboxylic acid 38116-61-9 28.40 1.2744 2 10818 C7H8N202 3,4-diaminobenzoic acid 619-05-6 92.67 1.2333 2... 

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