98279-90-4Relevant academic research and scientific papers
Nitropyridyl isocyanates
Holt, Jarle,Andreassen, Trygve,Bakke, Jan M.,Fiksdahl, Anne
, p. 259 - 264 (2007/10/03)
We hereby report the first preparation of 3-nitro-4-pyridyl isocyanate 9 and 5-nitro-2-pyridyl isocyanate 18. They were formed by Curtius rearrangement of the corresponding acyl azides 8 and 17, prepared from methyl 3-nitro-4-pyridinecarboxylate 6 via the hydrazide 7 and 5-nitro-picolinic acid 16, respectively. The substrates 6 and 16 were generated by nitration of methyl 4-pyridinecarboxylate 5 and nitration and oxidation of 2-picoline 14. 3-Nitro-4-pyridyl isocyanate 9 can be stored in dry solution and is stable at room temperature for several weeks while 5-nitro-2-pyridyl isocyanate 18 was less stable and should be used for synthetic purposes immediately.
Preparation of substituted 1,3-dihydro-2H-imidazo[4,5-c]pyridin-2-ones
Bakke, Jan M.,Gautun, Hanna S. H.,Svensen, Harald
, p. 585 - 591 (2007/10/03)
A new synthetic route to 6-substituted-imidazo[4,5-c]pyridin-2-ons from 4-aminopyridine has been investigated. 4-Aminopyridine protected as alkyl carbamates were nitrated with dinitrogen pentoxide to the corresponding methyl, i-propyl and t-butyl 3-nitropyridin-4-yl carbamates (5a-c) in 51-63% yields. Attempts to substitute these in the 6-position by the ONSH and the VNS techniques succeeded with butylamine and the t-butyl carbamate 9. From the methyl or t-butyl 3-nitropyridin-4-yl carbamates 5a, 5c 1,3-dihydro-2H-imidazo[4,5-c]pyridin-2-one (1) was formed in 73 and 39% yields, respectively. t-Butyl 6-N-butylamin-3-aminopyridin-4-yl carbamate (6) gave 6-butylamino-1,3-dihydro-2H-imidazo[4,5-c]pyridin-2-one (7) in 53% yield.
