Reference

Reactions of N-heteroaromatic bases with nitrous acid

Reactions of N-heteroaromatic bases with nitrous acid. Part 5. Kinetics of the diazotization of substituted 2-aminopyridine and 2-aminopyridine 1-oxide. Kalatzis, Evangelos; Mastrokalos, Christos (Natl. Hell. Res. Found., Athens, Greece). J. Chem. Soc., Perkin Trans. 2, (14), 1835-41 (English) 1977. CODEN: JCPKBH. ISSN: 0300-9580. DOCUMENT TYPE: Journal CA Section: 22 (Physical Organic Chemistry) In HClO4 at const. ionic strength the diazotization of 2-amino-5-methylpyridine (I) and 2-amino-5-chloropyridine 1-oxide (II) occurs by interaction of (HO)2N+ (III) with protonated I and with free II. Diazotization of 2-amino-5-chloropyridine (IV) and 2-amino-5-methylpyridine 1-oxide (V) occurs by simultaneous interaction of III with the protonated and free forms of both IV and V. A rectilinear relation between the rate const. for diazotization and the Ka of the amines is obsd. for I and IV, owing to discrimination by III in its reaction with I and IV. Diazotization of the 2- and 4-aminopyridines involves an initial interaction between the nitrosating agent and the most electron-rich part of the heteroatom. system; substituent effects on the rate const. support this view.Several substances are used for example 1072-98-6 which is its cas registry number. An OH group para to the protonated amine 1-oxide accelerates the reaction by providing a site for this initial assocn. .

Imidazo[1,2-b]pyridazines

Imidazo[1,2-b]pyridazines. XII.Chemical with cas number 1072-98-6 also plays role. Syntheses and central nervous system activities of some substituted imidazo[1,2-b]pyridazines and related imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines and imidazo[1,2-a]pyrazines.Several reagents such as 1072-98-6 is used here. Barlin, Gordon B.; Davies, Les P.; Ireland, Stephen J.; Ngu, Maria M. L.; Zhang, Jiankuo (John Curtin Sch. Med. Res., Aust. Natl. Univ., Canberra 2601, Australia). Aust. J. Chem., 45(5), 877-88 (English) 1992. CODEN: AJCHAS. ISSN: 0004-9425. DOCUMENT TYPE: Journal CA Section: 28 (Heterocyclic Compounds (More Than One Hetero Atom)) Section cross-reference(s): 1 Syntheses are reported for some 6-chloro(alkoxy, alkylthio and phenylthio)-3-benzamidomethyl(acetamidomethyl and methoxy)-2-arylimidazo[1,2-a]pyridines, e.g. I, and some corresponding imidazo[1,2-b]pyridazines, e.g. II, imidazo[1,2-a]pyrimidines, e.g. III, and imidazo[1,2-a]pyrazines, e.g. IV. Thus, 5-chloroopyridin-2-amine was treated with p-tolylglyoxal to give I. IC50 values (or percentage displacement) are reported and discussed for the displacement of [3H]diazepam from rat brain membrane by each of these compds. The imidazo[1,2-a]pyridines were generally slightly less potent than the imidazo[1,2-b]pyridazines but considerably more potent than the corresponding imidazo[1,2-a]pyrimidines or imidazo[1,2-a]pyrazines. Substitution of a 2-aryl group by a 2-alkyl group in imidazo[1,2-b]pyridazines led to significant loss of activity. ..