“On Water” Palladium Catalyzed Direct Arylation of 1H‐Indazole and 1H‐7‐Azaindazole
The C3 direct arylation of 1H-indazole and 1H-7-azaindazole has been a significant challenge due to the lack of the reactivity at this position. In this paper, we describe a mild and an efficient synthesis of new series of C3-aryled 1H-indazoles and C3-aryled 1H-7-azaindazoles via a C3 direct arylation using water as solvent. On water, PPh3 was effective as a ligand along with a lower charge of the catalyst Pd(OAc)2 (5 mol%) at 100 oC, leading to C3-aryled 1H-indazoles or C3-aryled 1H-7-azaindazoles in moderate to good yields.
Pyrazolopyridines. The Preparation of 1-Protected-1H-pyrazolopyridines and Attempts to Remove the 1-Substituent. Some Reactions of 1-Benzyl-1H-pyrazolopyridine and its 7-Oxide
1-Protected-1H-pyrazolopyridines and -1H-pyrazolopyridin-6(7H)-ones have been obtained from 1-substituted-5-aminopyrazoles , and the removal of the protecting groups has been investigated.Cyclisation of 1-substituted-5-aminopyrazoles with ethyl acetoacetate under acidic conditions or of the β-aminopropionic acid derivative (19) under the same conditions gave only the 1H-pyrazolopyridin-6(7H)-one isomer .N-Oxidation of 1-benzyl-1H-pyrazolopyridine (4) gave the 7-oxide (21) which yielded (20) and the less usual β-substitution product (22) with acetic anhydride.Nitration of either (4) or (21) gave only substitution at the para-position of the 1-benzyl substituent, but bromination or chlorination gave substitution at the 3-position of the heterocycle.
Dorgan, Roderick J.J.,Parrick, John,Hardy, Christopher R.
p. 938 - 942
(2007/10/02)
More Articles about upstream products of 75427-06-4