2-Amino-6- pyrid

The acetimidamide side chain originating from the reaction of the amino group in 3-aminopy-ridazine-4-carbonitrile with A.A-dimethylacetamide dimethyl acetal (vide infra) has been used for pyridine ring closure. Thus, treatment of 3- [(l-dimethylamino)ethylidene]amino pyrid-azine-4-carbonitrilc with lithium diisopropylamide at — 70°C gives 7V, (V7-dimethylpyrido-[2,3-c]pyridazine-5,7-diamine (10).21... 

Hoffman and Gronowitz - have applied this technique with marked success to the study of hydroxy-, amino-, and mercapto-thiophenes. Similarly, it has been shown that pyrid-4-one exists predominantly as such and that 4-hydroxypyridine 1-oxide is in equilibrium with comparable amounts of l-hydroxypyrid-4-one. - The method has also been used to investigate the structure of ions (see Section II,C, of article II by Katritzky and Lagowski). 

Alkylation of 3-amino-4-(pyrid-3-yl)furazan occurred at the pyridine ring (Scheme 111) (90EUP384288) (see also Scheme 187). 

By the same procedure, crystalline picrates of 5-amino- 1-cyclohexyl-2-methylimidazole (112 R = Me) (45%) [71JCS(C)1501] and 5-amino-l-(2-pyridyl) imidazole (96 R1 = pyrid-2-yl, R2 = H) (20%) [80JCS(P1)2316] were obtained from the sodium salts of the corresponding acids. 

Other workers began to study the structure of gramicidin. Christensen and coworkers12 isolated crystalline tryptophane and leucine from a hydrolysate. They found no evidence for a fatty acid component and established that phenylalanine, proline and hydroxyproline were absent from a hydrolysate. These workers isolated alanine diox-pyridate from a hydrolysate and also established that gramicidin contained a compound with vicinal hydroxy and amino groups. They speculated that this compound might be serine or isoserine and proposed that gramicidin contains two tryptophane, 2 leucine, 2 or 3 alanine and 1 hydroxyamino residues or a multiple of this composition. 

Z-aminO 1 -methy 1 6 phenylimidazo [4,5-b]-pyridine 2 aminO 3,7,8 trimethylimidazo[4,5 f]quinoxaline 2 aminO 3,4,7,8 tetramethyl 3H imidazO [4,5 f]quinoxaline inoxaline 3 aminO l,4 dimethyl SH pyrid [4,3 b] indole (Trp P I) and 3 aminO l methyl 5H pyrido [4,3 b]indole induced mutagenesis. Metabolic activation was required for positive results b... 

In the heterocyclic series, racemic 3-(fur-2-yl)alanine has been prepared from furfural using this approach. In addition, (3-(pyrid-3-yl)alanine, ° p-(quinol-3-yl)alanine, ° a p-(benzofuranyl)alanine derivative, 2-amino-3-(2,2 -bipyridi-nyl)propanoic acid, and some interesting derivatives of histidines—in particular 1-alkylhistidines with amphiphilic properties have all been synthesized using this methodology. The complete reaction sequence starting from an aldehyde and an A-acylamino acid derivative is shown in Scheme 7.150. 

A TBAF-induced elimination/rearrangement of certain 4- /t-butyldimethylsilyloxy-2-amino-l-aza-bicyclo[4.1.0]-hept-3-enes led to substituted l//-azepin-4(7//)-one derivatives in low to fair yields rearrangement to N-substituted pyrid-(177)-ones was a substituent-dependent competing process <2007T11167>. 

Cyclization of 3-cyano-2-[(3-hydroxypropyl)amino]-5-(4-pyridyl)pyri-dine-l -oxide (298) in POCl3 yielded 9 - c y a n o - 7 - (4 - pyrid yl)-.3,4-dihydro- 2//-pyrido[l,2-a]-pyrimidine l -oxide (299) (94EJM175). After heating 3-cyano-4-trifluoromethyl-6-phenyl-2-[(3-hydroxypropyl- and 3-hydroxybutyl)-amino] pyridines in boiling POCl3 for 1 h, the product was treated with aqueous NH4OH to yield 6-phenyl-8-trifluoromethyl-9-cyano-3,4-dihydro-2/7-pyr-ido-[l,2-a]pyrimidine and its 4-methyl derivative (01CHE329). 

Other, more complex halopyridazine A-oxides are known. 5-Amino-3,4- and 4-amino-3,5-dichloropyridazine form the corresponding 1-oxide, but 3,6-dichloro-4-methoxypyridazine is oxidized with monoperphthalic acid in ethereal solution to yield a mixture of the 1-oxide (12%), 2-oxide (5%), and 6-chloro-4-methoxy-3(2A)-pyrid-azinone and 6-chloro-4-methoxy-3(2A)-pyridazinone (up to 7%). Of aminopyridazines, the 3 isomer gives a resin with monoperphthalic acid, while the 2-oxide resulted from oxidation with... 

Chloro-6-(2-pyrid-2-ylethyl)amino 5-Chloro-6-(2-pyrid-4-ylethyl)amino 235-236 47... 

Chloro-6-(3-diethylamino-2-hydroxyproi5yl)amino Hydrochloride 5 -Chloro-6-phenacylthio 5-Chloro-6-[N-methyl-N-(2-pyrid-... 

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