- DIPYRIDOIMIDAZOLDERIVATIVES USEFUL IN TREATING CENTRAL NERVOUS SYSTEM DISORDERS
-
This invention relates to a series of substituted 3-oxo-pyrrolo[1,2-a]imidazopyridine derivatives of the formula 1 where X1-X4, R1, R2 and Ar are defined herein. In addition the invention relates to pharmaceutical compositions containing them and intermediates used in their manufacture. The compounds of the invention are ligands for the benzodiazepine site on the GABA-A receptor and display anxiolytic and anticonvulsant activity in animal models.
- -
-
-
- Process for the preparation of 2-nitro-3-aminopyridine, and the intermediates which are formed in the reaction
-
2-Nitro-3-aminopyridine is prepared by (a) reacting 3-aminopyridine with phosgen COCl2 or urea H2 NCONH2 to give N,N'-di-(3-pyridyl)-urea, (b) nitrating and N,N'-di-(3-pyridyl)-urea with nitric acid or with a mixture of nitric acid and sulfuric acid to give N,N'-di-(2-nitor-3-pyridyl)-urea, and (c) hydrolyzing said N,N'-di-(2-nitro-3-pyridyl)-urea to give 2-nitro-3-amino-pyridine. N,N'-di-(3-pyridyl)-urea and N,N'-di-(2-nitro-3-pyridyl)-urea, which are formed in the course of the reaction as intermediates are new compounds. The end product of the process, 2-nitro-3-aminonpyridine, is an intermediate in various specialized fields.
- -
-
-
- SYNTHESES WITH AROMATIC NITRAMINES, V. PHOTOCHEMICAL REARRANGEMENT OF NITRAMINOPYRIDINES
-
All three isomeric nitraminopyridines were photolysed in methanol with low-pressure mercury lamp (253.7 nm). 2-Nitraminopyridine yielded both 2-amino-3-nitro- and 2-amino-5-nitropyridines (isomer ratio 6.26 : 1). 3-Nitropyridine rearranged into both 4-nitro- and 2-nitro-3-aminopyridines (isomer ratio 1.28 : 1), whereas 4-nitraminopyridine gave 3-nitro-4-aminopyridine as the sole product. 1-Methyl-2-nitriminopyridine did not rearrange under the conditions applied, but 1-methyl-4-nitriminopyridine gave 3-nitro-4-methylaminopyridine.The latest product was also obtained when the same starting material was rearranged in conc. sulfuric acid.
- Sepiol, J.,Tomasik, P.
-
p. 159 - 164
(2007/10/02)
-
- NUCLEOPHILIC SUBSTITUTION IN o-NITROAZIDES OF THE PYRIDINE SERIES
-
The reactions of 2-nitro-3-azidopyridine and 3-nitro-4-azidopyridine with amines and anionic nucleophiles, viz., sodium hydroxide, sodium alkoxides, the sodium salt of p-thiocresol, and potassium cyanide, were investigated.A possible reaction mechanism is proposed.
- Kotovskaya, S. A.,Mokrushina, G. A.,Postovskii, I. Ya.
-
p. 303 - 306
(2007/10/02)
-
- Synthetic Approaches to some Aza-analogues of Benzimidazole N-Oxides. Part 1. The Imidazopyridine Series
-
The 3-oxide of 2-p-nitrophenylimidazopyridine (8) may be obtained in good yield by base-induced cyclisation of 2-nitro-3-(p-nitrobenzylamino)pyridine (18).It is also obtained in lower yield, along with p-nitrobenzoic acid and other cleavage products, by the corresponding reactions of bases with the N-ethoxycarbonyl, N-methylsulphonyl, and N-p-tolylsulphonyl derivatives of 2-nitro-3-(p-nitrobenzylamino)pyridine .Cleavage is the main reaction when N-(2-nitro-3-pyridyl)-N-phenacylmethanesulphonamide (17) is treated with bases: phenylglyoxal, or its Schiff base with 3-amino-2-nitropyridine, are possible intermediates in the cleavage process. 3-Nitro-2-(p-nitrobenzylamino)pyridine (31) is similarly cyclised in basic media to give the 1-oxide of 2-p-nitrophenylimidazopyridine (32).
- Andrews, Adrian F.,Smith, David M.,Hodson, Harold F.,Thorogood, Peter B.
-
p. 2995 - 3006
(2007/10/02)
-
- Pyrido[2,3-c]furoxan as a probable intermediate in the reaction of 2-nitro-3-azidopyridine with amines
-
Two parallel reactions, viz., cyclization of 2-nitro-3-azidopyridine to pyrido-[2,3-c]furoxan, which is aminated in the 6 position of the pyridine ring with opening of the furoxan ring, and reduction of the azido group to form 2-nitro-3-aminopyridine, occur in the reaction of 2-nitro-3-azidopyridine with amines. It was established that pyrido[2,3-c]furoxan reacts with amines in aqueous media in the 1-oxide form.
- Kotovskaya,Mokrushina,Postovskii,Polyakova
-
p. 480 - 483
(2007/10/02)
-
