6-aminopicolinic acid

Kubik and co-workers have developed a series of highly effective anion receptors based upon cyclic peptides. Cyclic hexapeptide receptors such as 17 consist of alternately linked L-proline and 6-aminopicolinic acid subunits [25]. A 1 1 binding stoichiometry for 17 and the sodium salt of ben-zenesulfonate was confirmed by a Job plot but in the case of the halide and sulfate sodium salts 2 1 host/guest complexes were found. This was confirmed by electrospray mass spectrometry and in the case of iodide a crystal structure of the 2 1 complex was obtained where the iodide was sandwiched between two cyclic hexapeptide receptors. 

Kubik and co-workers designed amide-based cyclopeptides 18-19 from two amino acid building blocks, Boc-L-prohne and 6-aminopicolinic acid benzyl ester [49, 50]. Cyclopeptide 18 formed sandwich-type 2 1 anion complexes with halide and sulfate anion with ranging from 10" to 10 in 80 % D2O/CD3OD. Crystal structure of 182 I showed that one iodide ion was located in a cavity between two cyclopeptide molecules, which interlocked perfectly the anion with six N I H-bonds ranging from 3.723 to 3.935 A (Fig. 5.16). As predicted, dicyclopeptide 19 which has more amide NH sites also displayed excellent binding constants (up to 10 M ) to anion with 1 1 stoichiometry. 

Amongst the more unusual reactions, 2,3-thiazolo fused pyrido[3,2-d]pyrimidines have been prepared from 3-aminopicolinic acid and 2-bromothiazoles, whilst a similar derivative resulted with allyl isothiocyanate (221 222) <72IJC602). Similar products are also produced in [3 + 3] reactions of 2-aminothiazoles (Section 2.15.5.7.1). 

The 6-methyl derivative (98, R = Me) was an important intermediate in the synthesis of analogs (e.g., 183) of folic acid. Korte has shown that 2-aminopyrido[3,2-guanidine carbonate with 3-aminopicolinic acid and that treatment of the same acid with ammonium thiocyanate or potassium cyanate yields the thioureido and ureido derivatives (100, X = S and X = 0). In contrast to the pyrido[2,3-d]pyrimidine system bsoth of these compounds could be cyclized by heat and the latter (100, X = O) is a likely intermediate in the synthesis of the dione (98) by the fusion with urea. 

Aminonicotinic or Amino- pyridine carboxylic Acids(Aminonicotinsaure or Amino pytidin carbons dure in Ger),HaN-(CjNH,) COOH. Aminonicotinic acids are aminopyridinecar-boxylic acids in which the carboxyl group is attached to position 3(if it is attached to position 2 the compd is called ami no pi colin ic acid). Four isomers of aminonicotinic acid with the amino groups in 2,4,5 or 6 positions are known. There is also an isonicotinic acid in which the carboxyl group is in position 4 and the amino group in position 3 (See also Aminopicolinic Acid)... 

Aminopicolinic Acid or Aminopyridinecarboxy lie A ctt/( Amino-pyridin-carbonsaure, in Ger), HaN(CBNH3)COOH. Aminopicolinic acids are aminopyridine carboxylic acids in which the carboxyl group is attached in position 2 (next to the nuclear N). Two isomers, 3-amino- and 4-amino- are described in Beil 22,541 [463]. If the carboxyl is attached to position 3 of aminopyridinic acid, the compd is called aminonicotinic flcirf(qv)... 

Somewhat similarly, 3-aminopicolinic acid with ethyl acetoacetate gave 2-methyl-l,5-naphthyridin-4(l//)-one (neat reactants, reflux, 4 h 13%).1000 3-Amino-2-pyridinecarbonitrile (31) with diethyl malonate gave 4-amino-1,5-naphthyridin-2(l//)-one (32) (neat reactants, EtONa, reflux, 7.5 h 36%).725... 

Dihydroxybenzo b -l, 5-naphthyridin-10(5//)-one (66), easily made by fusion of 3-aminopicolinic acid with phloroglucinol, underwent oxidation to 4-oxo-1,4-dihydro-l,5-naphthyridine-2,3-dicarboxylic acid (67) [HNO3 (d. 1.5), 20°C, then 95°C, 40 min %, after separation from a byproduct].17... 

Synonyms 4-Amino-3,5,6-trichloro-2-pyridine-carboxylic acid 3,5,6-trichloro-4-aminopicolinic acid 4-amino-3,5,6-trichloro-2-picolinic acid... 

Hydroxypicolinic acid (HPA) 3-Aminopicolinic acid (APA) Dihydroxybenzoic acid (DHB) a-Cyano-4-hydroxycinnamic acid (qCHCA) Sinapinic acid (SA)... 

Dimethyl-4 -nitropicolinic acid [4] was readily(21) prepared from commercially available 2,5-lutidine [3]. The reactive nitro group of picolinic acid [4] was smoothly substituted with 0-phenylenediamine to give m-aminopicolinic acid[5]. Treatment of [5] with nitrous acid resulted a benzotriazolylpicolinic... 

Derivatives of 2-aminonicotinic and 3-aminopicolinic acids are also suitable for the preparation of 2-oxo-IPs. Heating unsubstituted nicotinamide 116 with an... 

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