Pyridines, diamino-, reaction with

Relative rates have been determined for the competitive methylations and also acetylations of azines. Pyridazine reacts faster than pyridines in both reactions this is interpreted in terms of pair-pair electron repulsion and the a-effect. An additivity approach provides reasonable predictions of isomer ratios of quatemization products of pyridazine and other azines. Reinvestigation of the quatemization of various amino- and diamino-pyridazines with methyl iodide shows that both 1- and 2-methyl derivatives were usually formed. 3-Amino-6-chloropyridazine forms JV2-quateraary salts with a- and -halo esters and 1,4-dibromobutane, but with 1 -dibromo-ethane or 1,3-dibromopropane bicyclic products, are formed. Protonation and quatemization of l,4,S,6-tetrahydropyridazines takes place at position 1, this being the more basic nitrogen. ... 

Microwave irradiation can be used to make oxazolo[4,5-fc]pyridines and allows reaction with amides in lieu of acids when urea or thiomea are used, 2-ones (2-thiones) are obtained carbon disulfide with potassium hydroxide also leads to 2-thiones. The use of triphosgene and 2,3-diamino-pyridines can be used to made the analogous imidazo[4,5-b]pyridin-2-ones. Reaction with cyanogen bromide gives... 

The asymmetric synthesis of 2,3-diamino acids can be accomplished by the addition of chiral enolates to prochiral imines. For example, reaction of morpholine-2-one 103, derived from (S)-phenylglycinol, with N-benzyl ben-zaldimine in the presence of pyridine and para-toluenesulfonic acid at high... 

Synthetic Method 7 l,9-dimethyl-4-acetarnido-8-diethylaminoimidazo-phenoxazine (31) (procedure from U.S. Patent 4,604,462). 12 A mixture of 10 g of l,3-diamino-7-diethylamino-8-methylphenoxazin-5-ium chloride (Brilliant Cresyl Blue), 50 ml of acetic anhydride, 10 g of zinc dust, and 10 ml of pyridine was maintained at 85 to 90°C for approximately 1 h. After cooling to room temperature, the reaction mixture was poured into a mixture of water and toluene and the resulting aqueous layer was discarded. The toluene solution was washed twice, first with water and then with... 

Both amino groups of 3,5-diamino-4-phenylpyrazole reacted with EMME during 2 min. at reflux [83JCS(P1)11], The amino group at position 3 underwent a cyclocondensation reaction to form the bicyclic pyraz-olo[l,5-a]pyrimidine, while the amino group at position 5 participated in an addition reaction to give a (2,2-diethoxycarbonyl-l-ethoxyethyl)amino side-chain. Pyrazolo[l,5-a]pyridine (25) was obtained in 27% yield. 

Methyl-3,3 -bipyridine has been oxidized by permanganate to 3,3 -bi-pyridine-4-carboxylic acid. " 3,3 -Bipyridine carboxylic acids are easily decarboxylated and have been esterified and converted to amides, hydrazides, and acylazides. The Hofmann degradation, of the diamide of 3,3 -bipyridine-2,2 -dicarboxylic acid affords the expected 2,2 -diamino-3,3 -bipyridine, but some of the tricyclic system 108 is formed as well. A 2,2 -bis(acylazide) is converted to a similar tricyclic system with ethanol via the intermediate isocyanate, and several related reactions have been described. The simultaneous dehydration... 

Reaction of 4-chloro-6-fluoropyrido[3,4- pyrimidine 59 with [3-methyl-4-(pyridin-3-yloxy)phenyl]amine 60, followed by coupling the formed amine 61 with (3-azabicyclo[3.1.0]hex-6-yl)carbamic acid fi r7-butyl ester, afforded the substituted derivative 62 <2002EPP1249451>. Compound 59 was also reacted with 3-bromoaniline to give the 4-anilino derivative 63 that upon treatment with either methyl- or dimethylamine gave the corresponding 4,6-diamino derivatives 64 (Scheme 2) <1997W09726259, 1995W09519774>. 

The synthesis of the poly-(o-chlorophenyl)-imides was accomplished in two steps involving low-temperature reaction between the diamines and bis(phthalic anhydrides) in NMP followed by catalytic imidisation of the PCA directly in the reaction solutions using the catalytic complex pyridine acetic anhydride. The synthesis of polyimides from l,l-dichloro-2,2-di-(3-amino-4-aminophenyl)-ethylene proceeded homogeneously throughout the course of the reaction, as did reactions of 3,3 -diamino-4,4 -dichlorobenzophenone with the dianhydride of diphenyloxide-3,3, 4,4 -tetracarboxylic acid. As to reactions of 3,3 -diamino-4,4 -dichlorobenzophenone with the dianhydrides of pyromellitic and diphenylsulfone-3,3, 4,4 -tetracarboxylic acids, these were homogeneous at the PCA formation step but heterogeneous at the polyimide formation step. Some properties of these polyimides are given in Tables 3.3 and 3.4. 

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