Indazole 3-hydroxy

Indazole, 5,5-dimethyl-3-trifluoromethyl-4,5-dihydro-trichomonacidal activity, 5, 291 Indazole, 2-ethoxycarbonyl-reactions, 5, 269 Indazole, 3-fluoro-synthesis, S, 263 Indazole, 1-germyl-synthesis, 5, 236 Indazole, 1-glycosyl-synthesis, 5, 289 Indazole, 2-glycosyl-synthesis, 5, 289 Indazole, halo-reactions, S, 266 Indazole, 2-hydroxy-methylation, 5, 269 Indazole, 3-hydroxy-reactions, S, 264 Indazole, 6-hydroxy-diazo coupling, 5, 86 Indazole, hydroxyphenyl-synthesis, S, 288 Indazole, 3-iodo-synthesis, S, 241 Indazole, l-isopropyl-3-phenyl-reduction, 5, 243 Indazole, 3-mercapto-1 -substituted tautomerism, 5, 265 Indazole, methoxy-... 

Chemical Name 21-ester of 1(1-benzyl-1 H-indazol-3-yl-oxy]-acetic acid with 11/3,17a, tri-hydroxy-pregn-4-ene 3 0-dione... 

Pseudo-Cross-Conjugated 1 -Hydroxy-6,7,8,9-Tetrahydropyridazino[1,2-a]indazol-... 

Acid- and base-promoted methods have also been used in the syntheses of pyrazoles. Hydrogenation of methyl 2-Cbz(hydrazine)-3-hydroxy-4,4-dimethoxybutanoate 11 followed by cyclization in the presence of trifluoroacetic acid afforded the first asymmetric synthesis of the (4S,5.R)-5-carbomethoxy-4-hydroxy-A2-pyrazoline 12 <00TL8795>. Reaction of 2-nitrobenzyl triphenylphosphonium ylide (13) with aiyl isocyanates afforded 2-aryl-2H-indazoles 14 <00TL9893>. Base-promoted reaction of nitrobenzenes 15 with aryl imines 16 afforded aryl pyrazoles 17 . 

A much improved synthesis of a dioxino[23-e]indolemethanol was described. This procedure now allows the preparation of multigram quantities of the enantiomerically pure compound. Application of this methodology to different 5-hydroxy heterocycles enables access to furo[33- [l,4]benzodioxin, thieno[33-/l[l,4]benzodioxin and l,4-dioxino[23-e]indazole ring systems <99S1181>. 

The effect of amino, hydroxy or mercapto substituents is to increase hydrogen bonding properties. However, if stable hydrogen bonds are formed in the crystal, then this can decrease their solubility in water (63PMH(l)177), e.g. indazole and benzimidazole are less soluble than benzoxazole. 

Indazolinone exists as such (227) in the solid state but only as a minor isomer (15%) in DMSO solution, where the 3-hydroxy-17/-indazole tautomer (228) predominates (85%) (86JCS(P2)1677). No evidence for the existence of 3-hydroxy-2 f-indazole (229) has been found. 

Diazo coupling is expected to occur only with highly reactive systems, and experiment bears this out. Diazonium ions couple with the anions of A -unsubstituted imidazoles at the 2-position (e.g. 157 yields 158) and with indazoles (159) in the 3-position. In general, other azoles react only when they contain an amino, hydroxy, or potential hydroxy group, e.g. the 4-hydroxypyrazole (160), the triazolinone (161) and the thiazolidinedione (162) (all these reactions occur on the corresponding anions). 

Thermal cyclization was also the route employed to prepare 9-hydroxy-7-methyl-l/f-pyrazolo[3,4-/]quinoline (74) from the 6-aminoindazole/ethyl acetoacetate condensation adduct shown in Equation (41) <92JMC4595>. The hydroxyl substituent of compound (74) was then converted (POCl3, DMF) to a chloro, which in turn was displaced by treatment with aryl amines to give tricyclics with potent in vivo immunostimulatory activity like that noted for regioisomeric l//-imidazo[4,5-/]quinolines but unlike the inactive pyrazolo[4,3-/]quinolines. Although it was noted with some interest that none of the linear tricyclic isomer had been isolated, this finding actually parallels that reported earlier for the similar condensation of 1- and (V(6)-alkyl and unsubstituted 6-amino-indazoles with diethyl ethoxymethylenemalonate <83JHC1351>. 

Title 6-Hydroxy-indazole Derivatives for Treating Glaucoma... 

Pyrazin 3-Amino-2-cyan-5-(2-furyi)-E9b/2, 31 If. (N-Oxid-Red.) lH-Pyrazol 4-Diazo-5-oxo-3-phenyl-4,5-dihydro- X/4, 525/ El4b, 1114 (Amin 4- NaN02) lH-(Pyrimido 5,4-f]indazol) 5(bzw. 9)-Hydroxy- E8b, 849 (Pyrimidin-Ringschl.)... 

Amino-3-methoxy-2-(3-pyridyl-methylen-amino)-E15/2, 1809 [(NC)2CH-NH2 + R-CHO] Azetidin 3-Azido-4-(4-methyl-phenyl)-2-oxo- E16b, 371 (Nj-C-CO-Cl + Imin) Furazan 4-(Anilinomethylen-amino)-3-methyl- E8c, 673 (NH2 -> N=CH —NH —Ar) Hydrazin l,2-Bis-[2-pyrrylme-thylen]- -1-oxid X/2, 121 1 H-(Imidazo 1,2-a]-l,3,5-benzotriaze-pin), 10-Hydroxy-2,3-dihydro E9d, 476 [1 -(2-NH2 — Ar) — 2-imino — imidazolidin/COCl2) Imidazo[4,5-f indazol 5,6-Dimethyl-... 

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