5 arylamino-3-hydroxy

By taking advantage of the well-known conversion of the cyano into the carbamoyl group under the influence of alkaline hydrogen peroxide, A-aryl-A -cyanoisothioureas (120) (as their stable sodio derivatives) are directly cyclizable, in approximately 50% yield, to 5-arylamino-3-hydroxy-1,2,4-thiadiazoles (119) in one stage.130... 

Malonsaure-arylamid-diethylester und Methyl-hydrazin cyclisieren bei 20° in Ethanol zu 5-Arylamino-3-hydroxy-1 -methyl-1 H-pyrazolen485 ... 

Arylamino-3-hydroxy-l-methyl- 446 l-Aryl-4-arylazo-5-hydroxy- 437 l-Aryl-4-arylazo-5-hydroxy-3-mcthyl- 531, 642... 

Wu et al. reported the total synthesis of clausenaquinone A (112) using a palladium(ll)-mediated oxidative cyclization of the 2-arylamino-5-methoxy-l,4-benzoquinone 874 (107). This total synthesis was undertaken to establish the structure of natural clausenaquinone A (112). The key intermediate, 2-(3-hydroxy-4-methylanilino)-5-methoxy-l,4-benzoquinone (874), required for this synthesis, was obtained by the reaction of 5-amino-o-cresol (873) with 2-methoxy-l,4-benzoquinone (872) which was readily obtained by oxidation of methoxyhydroquinone (871). The palladium(ll)-mediated oxidative cyclization is non-regioselective. Thus, the cyclization of the 2-arylamino-5-methoxy-l,4-benzoquinone 874 with palladium(Il)... 

N-Acetylderivate der Aminocyclenole entstehen. Unter Nachbargruppen-beteiligung werden hierbei l-Arylamino-2(cis)-acetoxy-3(trans)brom-4-hydroxy (bzw. -acetoxy)-cyclane als einzige Produkte gebildet 50),... 

Arylisocyanid-dicbloride liefem unter milden Bedingungen mit Hydroxy-guanidinen die ent-sprechenden 3-Amino-5-arylamino-l, 2,4-oxadiazole in maBiger Ausbeute77. 

Auch die im alkalischen Medium ablaufende Isomerisierung der 5-Alkoxy-3-arylamino-l,2,4-oxadiazole zu 5-Hydroxy-1H-1,2,4-triazolen (s. S. 517) diirfte nach anderen Mechanismen ablaufen als die nach Boulton-Katritzky aufgefiihrten Beispiele274 z.B. ... 

Benzylische Acyloxy-Gruppen wie z.B. in 4,7-Diacetoxy-6-methoxy-2-methyl-l,2,3,4-te-trahydro-isochinolin werden bei der Reaktion mit primaren Aminen unter milden Bedin-gungen durch eine Alkylamino- Oder Arylamino-Gruppe ersetzt gleichzeitig wird die zwei-te Acetoxy-Gruppe im Molekul hydrolysiert, so daB man mit Ethylamin bzw. Anilin 4-Ethylamino-7-hydroxy-6-methoxy-2-methyl- (82%) bzw. 4-Anilino-7-hydroxy-6-meth-oxy-2-methyl-l,2,3,4-tetrahydro-isochinolin (66%) erhalt1. 

A synthesis of a-arylamino acids has been reported using Schiff-base anions 61 derived from amino esters, which are arylated with fluorobenzene complex la to give a-aryl imino esters 62 in 48-76 % yield (R = H, Me, CH2Ph) [49]. Using the same procedure, these authors reported a convenient synthesis of optically pure a-aryl amino acid precursors 64 by enantioselective substitution of fluorobenzene complex la using the Schiff base of L-alanine methyl ester with f 1 R.2R.5 R -2-hydroxy-3-pinanone 63 in the presence of LDA (Scheme 30) [50]. 

Reactions of 1,2,4-thiadiazoles with radicals and electron deficient species are virtually unknown. Catalytic and dissolving metal reductions usually result in S—N bond cleavage. For example, the 5-anilino-3-hydroxy derivative (51) gives a good yield of l-phenyl-2-thiobiuret (52) on Zn-HCl reduction (Scheme 27). Reduction of the diamino derivative (53) gives amidinothiourea (54) from which it may be prepared by oxidation (Scheme 28). Under similar conditions, cleavage of the 3,5-diphenyl derivative (55) results in loss of sulfur and formation of benzylbenzamidine (56 Scheme 29). Reduction of 5-alkylamino-or 5-arylamino-3-alkylthio derivatives (57) with H2S in pyridine-triethylamine or sodium in liquid ammonia yields 1-substituted dithiobiurets (58 Scheme 30). 

An alternative route that also gives good yields of 3-arylphthalazinium-l-olates (e.g., 205 Ar = Ph) has been described by Lund and involves thermolysis (100-120 C) of A-arylamino-3-hydroxyphthalimidines (197). This transformation (197 - 196) probably proceeds by formation of a hydrazide (198) prior to cyclodehydration (198 - 1%). Compound 205 (Ar = Ph) is obtained in low yields by lithium aluminum hydride reduction of 4-hydroxy-2-phenyl-l(2//)-phthalazinone 207 (R = OH, = Ph). ... 

Nitrosation of 4-hydroxythiocouTnarin leads to the 3-oxiniino-4-keto derivative (45). Replacement of the 4-hydroxy group by a chloro (46), arylamino (47), or phenylhydrazino group (48) is readily accomplished by heating the compound with phosphorus pentachloride in chloroform, aniline, or phenylhydrazine, respectively. ... 

Amino-1 -hydroxy-1,2-dihydro-E19b, 943 (Carben + En) Arylamino- XI/1, 165 Arylazo-chlor- E16d, 92 (OH -+ Cl)... 

N-Substituted 3-hydroxy-5-arylamino-isothiazole-4-carboxamidines are potent, orally available, in vitro MEKl allosteric inhibitors, <2006BML5561> while amino-heterocycle-substituted isothiazoles are inhibitors of the TrkA kinase in cell assays <2006BML3444>. Benzisothiazolone derivatives are inhibitors of different serine proteases, such as cell tryptase <1998JME4854> and HLE <2003EJM421>. 

The 2-amino and 2-hydroxy groups of the dihydropyrido[2,l-6]quinazo-linones 360 and 440 were converted to a 2-(arylamino) group by treatment with anilines in refluxing acetic acid for 2.5 hr under a nitrogen atmosphere. The pyrido[2,l-6]quinazolinones 441 and the 1,4-dihydro de-... 

Photochemical rearrangement of 2-arylamino-l-(4-tert-butylphenoxy)-9,10-anthraquinones involves migration of the tert-butylphenoxy group either to the peri carbonyl oxygen atom to produce 2-arylamino-9-(4-tert-butylphe-noxy)-l,10-anthraquinones, or to the nitrogen atom to give 2-aryl(4-tert-butylphenyl)amino-l-hydroxy-9,10-anthraquinones. ... 

Eine analoge Synthese von 2-Arylamino-4-hydroxy-l,3-thiazolen (bis 36%) ist ausge-hend von (a-Chlor-acyl)-isothiocyanaten und Aminen moglich, ohne daB intermediare N-Chlo-racetyl-thiohamstoffe isoliert werden704,1075. 

Die Curtius-Umlagerung von N-substituierten N-Aryl-carbamidsaure-aziden liefert als Pri-marprodukt Arylamino-isocyanate, die durch intramolekulare Cyclisierung 3-Hydroxy-1H-indazole liefern651. 

Arylamino-5-arylazo- 248 2-Arylamino-5-formyl- 263 2-Arylamino-4-hydroxy- 127 2-Arylamino-5-oxalyl- 265 2-Aryl-5-(2-aryl-4,5-dihydro-l,3-thiazol-... 

A simple and efficient route, which gives 5-hydroxy-l,3,6,8-tetrasubstituted or 1,3,8-trisubstituted pyrido[2,3-rf]pyrimidinetriones in 62-94% yield, is the thermal reaction of 6-(alkylamino)- or -(arylamino)uracils with ethyl malonates at 220-250 °C.566... 

The reaction of 2-arylamino-5-hydrazino[l,2,4]thiadiazoles (115) with methyl chloroformate gives 6-arylamino-3-hydroxy[l,2,4]triazolo[3,4- >][l,3,4]thiadiazoles (116) with carbon disulfide the corresponding 3-sulfonyl derivatives (117) are formed (Scheme 10) <92IJC(B)467>. 

R = Me2C=CH-CH2-CH2) with hydrazine hydrate leads to carbamate intermediates, which undergo cyclization to give 5-hydroxy-5.6-dihydro-4/f-l,3,4-oxadiazin-2(3//)-ones 311. The thermal dehydration of 311 gives 1,3,4-oxadiazin-2(3//)-ones 312 <2003CHE1057>. In contrast to the case with hydrazine hydrate, the reaction of aromatic hydrazines with l,3-dioxolan-2-ones 310 provides 3-arylamino-4-hydroxyoxazolidin-2(3//)-ones 313. 

The reaction of sugar isothiocyanates with aminosugars described above has also been studied with 1-amino (alkyl and arylamino)-l-deoxy-D-fructose 143 (Scheme 32). Thus, treatment of different 0-acylated sugar isoth-iocyanates with D-fructosamines 143 gave M-glycosyl-5-hydroxy-5-tetritolyl-imidazolidine-2-thiones 144 as pairs of diastereomers in almost quantitative yield [ 152]. The reaction times were shorter (15-20 min) for fructosamine or its M-methyl derivatives than in the cases of N-aryl derivatives (8-24 h). Acid-catalyzed dehydration of 144 with ethanolic TFA at rt led to 147 in 65-77% yield. These compounds can be considered simultaneously as M-nucleosides and acyclic C-nucleosides of imidazoline-2-thiones. 

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