157012-18-5Relevant academic research and scientific papers
Synthesis of 2,4-diaminopyrrolo[2,3-d]pyrimidines via thermal Fischer indolization. Pyrazole formation with ytterbium triflate catalysis
Bundy,Schwartz,Palmer,Banitt,Watt
, p. 1471 - 1477 (2000)
The high-yield synthesis of the 2,4-diaminopyrrolo[2,3-d] pyrimidine 4 (PNU-87663) via a Bischler-like alkylation-cyclization sequence was reported earlier. We describe herein an alternative synthesis of this potent antioxidant and several analogs based on the thermal Fischer indolization, starting from hydrazino substituted pyrimidines 5 and 13. In several cases where the thermal Fischer indolization failed, attempts to catalyze the reaction with Lewis acids, especially ytterbium triflate, led to the surprising and unprecedented formation of pyrazolo[3,4-d]pyrimidines, e.g. 1-methyl-3-phenyl-4,6-di-1-pyrrolidinyl-1H-pyrazolo[3,4-d]pyrimidine (24), with the loss of the elements of methane. Mechanistic details of this transformation remain to be investigated.
Pharmaceutically active bicyclic-heterocyclic amines
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, (2008/06/13)
The pharmaceutically active bicyclic heterocyclic amines (XXX) STR1 where W1 is --N= or --CH=; W3 is --N= or --CH=; W5 is --N= or --CR5 -- with the proviso that W5 is --CR5 -- when both W1 and W3 are --N= which are useful as pharmaceuticals in treating mild and/or moderate to severe head injury, subarachnoid hemorrhage and subsequent ischemic stroke, asthma and reduction of mucous formation/secretion in the lung and other diseases and injuries.
