Imidazo pyridines 4,5,6,7-tetrahydro

Imtdazo[4,5-c]pyridtne, 4,5,6,7-tetrahydro-synthesis, 5, 623, 640, 641 Imidazo[4,5-c]pyridine-6-carboxylic acid, 4,5,6,7-tetrahydro-synthesis, 5, 623, 641 Imidazopyridines as anthelmintic, 1, 202 synthesis, 5, 462 Imidazo[l,2-n]pyridines deuterium exchange, 5, 611 diazo coupling, 5, 614 Dimroth rearrangement, 5, 613 halogenation, 5, 611 hydrogenation, 5, 614 Mannich reaction, 5, 612 nitration, 5, 612 1-oxides... 

S,5S)-6-(9-P-D-Glucopyranosyl-tetrahydro-5-(hydroxymethyl)imidazo [1,2-a] pyridine-6,7,8-triol (123)... 

Anilinomethyl-glucoimidazole (129) (5tf,6/ ,7S,SS)-5-(Hydroxymethyl)-2-(phenylamino)methyl-5,6,7,8 -tetrahydro-imidazo [ 1,2-a] pyridine- 6,7,8-triol... 

The presence or absence of the dioxolane protecting group in dienes dictates whether they participate in normal or inverse-electron-demand Diels-Alder reactions.257 The intramolecular inverse-electron-demand Diels-Alder cycloaddition of 1,2,4-triazines tethered with imidazoles produce tetrahydro-l,5-naphthyridines following the loss of N2 and CH3CN.258 The inverse-electron-demand Diels-Alder reaction of 4,6-dinitrobenzofuroxan (137) with ethyl vinyl ether yields two diastereoisomeric dihydrooxazine /V-oxide adducts (138) and (139) together with a bis(dihydrooxazine A -oxide) product (140) in die presence of excess ethyl vinyl ether (Scheme 52).259 The inverse-electron-demand Diels-Alder reaction of 2,4,6-tris(ethoxycarbonyl)-l,3,5-triazine with 5-aminopyrazoles provides a one-step synthesis of pyrazolo[3,4-djpyrimidines.260 The intermolecular inverse-electron-demand Diels-Alder reactions of trialkyl l,2,4-triazine-4,5,6-tricarboxylates with protected 2-aminoimidazole produced li/-imidazo[4,5-c]pyridines and die rearranged 3//-pyrido[3,2-[Pg.460]

Furan 2-Aminomethyl-5-(2,4-dioxo-1,2,3,4-tetrahydro-pyrimidino)-2,5-dihydro- IV/lc, 578 Imidazo(l,2-a]pyridin 1,5-Dimethyl-8-nitro-7-oxo-l,2,3,7-tetrahydro-E15/3, 2790 [cycl. (R2N)2C = CH-N02 4- Diketen] 1,3-Oxazol 4-Cyan-5-(diethoxy-methylen-amino)- E4, 565 (Het — NH2 + Orthoester) Pyrazin 3-Amino-2-methoxycarbo-nyl-5-propanoyl- E9b/2, 324 (H - CO-R)... 

Imidazo l,2-a pyridin l-Isopropyl-5-methyl-8-nitro-7-oxo-1,2,3,7-tetrahydro- E15/3, 2790 [cycl. (R2N)2C = CH-N02 +... 

There is little published work on the catalytic hydrogenation of the imidazo[l,2-fl]pyridines (63), but what there is indicates that reduction of the pyridine ring takes place preferentially to give the 5,6,7,8-tetrahydro derivatives (64) (77HC(30-2)117, 73JMC1272). 

Intramolecular cyclization of the imidazoles (433) also gave rise to 4,5,6,7-tetrahydro-imidazo[4,5-c]pyridines (434) (75JHC1039). 

Cleavage of perhydro-imidazo[l,2-a]pyridine (211) with diisobutyl-aluminum hydride produces 1,4-diazacyclononane (82TL4I8I). Addition of phenylmagnesium bromide to 2-phenyl-6,7,8,8a-tetrahydro-3//,5//-imi-dazo[l,2-a]pyridin-l-oxide (224) resulted in the formation of 2,2-diphenyl-perhydro-imidazo[l,2-a]pyridin-l-ol (225) (83AP47). 

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