- An improved synthesis of 9-benzyladenine: A model for adenosine and its analogues
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An improved synthesis of 9-benzyladenine (I), a model for a variety of biologically and therapeutically significant adenine nucleosides, has been reported. The target compound was synthesized by condensation of 1-benzyl-4-cyano-5-methoxymethyleneiminoimidazole (14) with guanidine. Compound 14 was prepared from 5-amino-1-benzyl-4-cyanoimidazole (5), which in turn was prepared by reaction of benzylamine with ethyl (Z)-N-(2-amino-1,2-dicyanovinyl) formimidate (13). The latter was synthesized by reaction of diaminomaleonitrile (6) with triethyl orthoformate.
- Sun,Hosmane
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- Total synthesis of cyclic ADP-carbocyclic-ribose, a stable mimic of Ca2+-mobilizing second messenger cyclic ADP-ribose
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The synthesis of cyclic ADP-carbocyclic-ribose (cADPcR, 4) designed as a stable mimic of cyclic ADP-ribose (cADPR, 1), a Ca2+-mobilizing second messenger, was achieved using as the key step a condensation reaction with the phenylthiophosphate-t
- Shuto,Fukuoka,Manikowsky,Ueno,Nakano,Kuroda,Kuroda,Matsuda
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p. 8750 - 8759
(2007/10/03)
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- Rearrangements in Heterocyclic Synthesis: A Novel Translocation of an (N-Amino-N-methylamino)methylene Group from a Heterocyclic N-Amino-N-methylformamidine Side Chain to the Vinylogous Nitrile Function
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Reaction of the imidate 1-benzyl-4-cyano-5imidazole (5) with an equivalent of hydrazine provided 1-amino-9-benzyl-6-iminopurine (6), which, upon treatment which excess hydrazine, rearranged to 9-benzyl-6-hydrazinopurine (7).Reaction of 5 with methylhydrazine gave N-amino-N-methyl-N'-(1-benzyl-4-cyanoimidazol-5-yl)formamidine (8b).Thermolysis of 8b in refluxing toluene-methanol, catalyzed by trifluoroacetic acid, provided an equimolar mixture of 5-amino-1-benzyl-4-cyanoimidazole (9) and 3-(5-amino-1-benzylimidazol-4-yl)-1-methyl-1,2,4-triazole (10).Compound 9 was recycled to 8b via 5.The structure of 10 was established by spectral data coupled with an unequivocal synthesis.The conversion 8b to 10 represents a novel "translocative" rearrangement involoving the transfer of an NH2N(Me)CH= group from the imidazole 5-position to the nitrile function at position 4.Successful application of the rearrangement to the analogous pyrazole system is demonstrated.The rearrangement carries useful practical implications in the synthesis of the otherwise not easily accessible heterocycles of potential biological and medicinal significance.
- Hosmane, Ramachandra S.,Lim, Benjamin B.,Burnett, Friedrich N.
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p. 382 - 386
(2007/10/02)
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