3-Methyl-7- pyrazolo pyrimidine

Pyrazophos ethyl 2-[(diethoxyphosphinothioyl)oxy]-5-methyl pyrazolo[1,5-aJ pyrimidine-6-carboxylate Hoe 2873 Afugan Curamil... 

Uber die Cyclisierung von 3(5)-(3-Oxo-alkanoylamino)-lH-pyrazolen werden die 5-Hydroxy-Isomeren erhalten2171. Aus 3(5)-Amino-5(3)-hydroxy-l H-pyrazol und 3-Oxo-butansaure-ethyl-ester ist 2,7-Dihydroxy-5-methyl-(pyrazolo[l,5-a]pyrimidin (74% Schmp. > 300°) zugang-lich2174. 3,5-Diamino-lH-pyrazole kondensieren unter analogen Bedingungen zu 2-Amino-7-hydroxy-5-methyl-2165 2175 ... 

Ahnlich der Reaktion von 3(5)-Amino-lH-pyrazolen mit 3-Oxo-alkansaure-estern verlauft die Umsetzung mit 4-ChLorcarbonyl-3,5-dimethyl-l,2-oxazolen als Dicarbonyl-Aquivalent. Nach Acylierung des 3(5)-Amino-lH-pyrazols und Offnung des 1,2-Oxazol-Rings werden 6-Acetyl-5-hydroxy-7-methyl-[Pg.682]

In another synthesis of (fused) pyrimidine-4-thiones, o-aminonitriles were condensed with thioacetamide in ethanol that had been saturated with hydrogen chloride. Unstable 1,3-thiazines (such as 130) could be isolated as intermediates, but a final alkaline treatment gave, for example, 6-methyl-pyrazolo[3,4-d]pyrimidine-4-thione (131). When an unsubstituted 2-position was required, thioformanilide in dimethylformamide became the preferred reagent (loss of phenyl group). Yields varied from moderate to good, in favorable cases, but the reaction can be somewhat erratic.184,185 For another 4-thione-generating reaction, see Section VI,A,4. 

Ethyl 2-diethoxythiophosphoryloxy-5-methyl-pyrazolo (1,5-a) pyrimidine-6-carboxylate. See Pyrazophos... 

Synonyms 0,0-Diethyl-0-(5-methyl-6-ethoxy-carbonyl-pyrazolo (1,5-a) pyrimid-2-yl-thionophosphate Ethyl 2-diethoxythiophosphoryloxy-5-methyl-pyrazolo (1,5-a) pyrimidine-6-carboxylate Phosphorothioic acid, 0,0-diethyl ester, O-esterwith pyrazolo (1,5-a) pyrimidin-2-ol Empirical C14H20N3O6PS Properties Olive brn. to dk. grn. cryst. solid sol. in most org. soivs. sol. 4.2 mg/l in water (20 C) m.w. 

The palladium-catalysed reaction of the pyrazolo-pyrimidine derivative (141) with 3-bromotoluene may result in arylation at the 3-position in the pyrazole ring or at an sp hybridized site in the 7-methyl side-chain depending on the base and ligands used. After initial insertion of the palladium catalyst into the aryl halide bond, palladation of (141) occurs by a concerted metalation-deprotonation pathway and is followed by reductive elimination. Concerted metalation-deprotonation is also likely in the palladium-acetate-catalysed reaction of imidazo[l,2-a]pyridines with aryl bromides to give 3-substituted derivatives such as (142). A careful mechanistic study of the arylation of pyridine A-oxide by bromotoluene, catalysed by palladium acetate and t-butylphosphine, has shown that direct reactions of an aryl palladium complex with... 

Oxidative cyclization of the fully methylated 6-(benzylidenehydrazino)uracils (536) provides a 90% yield of the pyrazolo[3,4-J]pyrimidines (537) (75BCJ1484). 

Cyclopent-2-en-l-one, 2-hydroxy-3-methyl-synthesis, 3, 693 Cyclopentenone, 4-methoxy-formation, 1, 423 Cyclopenthiazide as diuretic, 1, 174 Cyclopent[2,3-d]isoxazol-4-one structure, 6, 975 Cyclophane conformation, 2, 115 photoelectron spectroscopy, 2, 140 [2,2]Cyclophane conformation, 2, 115 Cyclophanes nomenclature, 1, 27 Cyclophosphamide as pharmaceutical, 1, 157 reviews, 1, 496 Cyclopiloselloidin synthesis, 3, 743 Cyclopolymerization heterocycle-forming, 1, 292-293 6H-Cyclopropa[5a,6a]pyrazolo[l,5-a]pyrimidine pyrazoles from, 5, 285 Cydopropabenzopyran synthesis, 3, 700 Cyclopropachromenes synthesis, 3, 671 Cyclopropa[c]dnnolines synthesis, 7, 597 Cyclopropanation by carbenes... 

CN l-[[3-(4,7-dihydro-l-methyl-7-oxo-3-propyl-l//-pyrazolo [4,3- pyrimidin-5-yl)-4-ethoxyphenyl]sulfonyl]-4-methylpiperazine... 

Chloro-3-ethoxy-2-methyl-2//-pyrazolo[4,3-reacted with the sodium salt of dimethyl malonate in DMF to give (pyrazolo[4,3-c/]pyrimidin-7-yl)malonate (499) [88JAP(K)246377]. 

N-( l-Acetyl-3-methyl-5-pyrazolyl)aminomethylenemalonate (1103) was cyclized to pyrazolo[l,5-a]pyrimidine-6-carboxylate (1102, R = 2-Me) in 82% yield by heating in boiling diphenyl ether for 10 min (74AP177). 

Pyrazolo[l,5-a]pyrimidine-6-carboxylates (1402) were prepared in 70% yields in the reaction of 3-aminopyrazoles and diethyl amino(trichloro-methyl)methylenemalonate in boiling ethanol in the presence of sodium ethoxide for 6 hr (78JPR533). 

Methylation of some form of 6-mercaptopurine in man has been established by the identification of 6-(methylsulphinyl)-8-hydroxypurine (LXV), 6-(methylthio)uric acid (LX), and 6-(methylthio)-8-hydroxy-A -glucuronide (LXVll). The oxidation of 6-(methylthio)purine to 6-(methylthio)-8-hydroxy-purine (LXVl) is mediated much more rapidly by rabbit liver aldehyde oxidase than by xanthine oxidase, and the oxidation is not inhibited by 4-hydroxy-pyrazolo [3, 4-d] pyrimidine [269], which is known to be an effective inhibitor of xanthine oxidase, and consequently, of the oxidation of 6-mercaptopurine [12,268]. 

New pyrazolo[l,5-a]pyrimidine derivatives have been synthesized. These compounds are potent angiotensin-ll receptor antagonists <99CPB928>. Pyrazolot3,4-ri]dihydropyridazinone derivatives have been obtained by the reaction of 5-methyl-4-methoxycarbonyl-3-acetyl-1-phenylpyrazole with different hydrazines <99TL3891>. A direct synthesis of pyrazolo [3,4-b]pyridines 69 from pyrazole 67 and benzothiazole 68, through a Friendlander condensation, has been described <99SC655>. 

X-Ray diffraction studies of l-(4,6-dimethylethylsulfanyl-l-//-pyrazolo[3,4-r/ pyrimidinyl)-3-(5-methyl-6-methyl-sulfanyl-4-oxo-l,5-dihydropyrazolo[3,4-, pyrimidin-l-ylpropane 69, the Leonard trimethylene linker, showed unusual U-moieties formed due to intramolecular 7t—Jt stacking interactions, CH- -N, CH- -S, and S- -S interactions <2006JST106>. 

Reaction of 2-amino-3-phenylazo-5-methyl-6,7-dihydropyrazolo [ 1,5-a] -pyrimidine-7-one (209) with ACOH/H2SO4 gives the pyrazolo[l,5-a]-pyrimidine derivative 210 (77JHC155). This reaction can be looked at as electrophilic substitution of the arylazo function by the proton. Similarly, 4,5,6,7-tetrahydro-2-phenyl-3-phenylazo-5-oxopyrazolo[l,5-a] pyrimidine gives 4,5,6,7-tetrahydro-2-phenyl-5-oxopyrazolo[l,5-a]pyrimidine 212 by the action of acetic/hydrochloric acid (75T63). 

Pyrazolo[l,5-fl]pyrimidine derivative 222, when treated with water, partially changes into 223. This reaction is assumed to proceed via attack of base at C-7 (81CPB1548 81JHC163). The C-6=C-7 double bond in 222 adds a variety of electrophiles (81CPB1548 81JHC163 83H(22)1913). Thus, treatment of 222 with acetic acid and water at 70°C affords 8-carbeth-oxy-3-substituted-7-methyl-6W-pyrazolo[ 1,5-a]-1,3-diazepin-6-one (224). Compound 222 reacts with phenylhydrazine to yield the pyrazolo[3,4-6,7]pyrazolo[l,5-n]pyrimidine derivative 225. The double bond in 222 also adds diazoalkanes to yield the pyrazolo[l,5-a]pyrimidine derivatives 226 (81CPB1548 81JHC163 83H(22)1913). 

Diphenylhydrazine (Ph2NNH2) is converted into indazole (215) by Cl2C = NMe2. Oxidative cyclizations are also known thus, fully methylated 6-(benzylidenehydrazino)uracils (216) on photolysis or in hot AcOH give the pyrazolo[3,4-d]pyrimidines (217) (75BCJ1484,92KGS219). 

Pyrazolo[5,1 -6]pyrimidine HNMR, 5, 307 <75CJC119 Pyrazolo[5,l-6]pyrimidine, 8-methyl-UV, 5, 307 <62CPB620 ... 

Ethoxyphenyl)-l-methyl-3-n-propyl-l,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (10.0 g, 32.1 mmol) was added portionwise to chlorosulfonic acid (20 ml) at 0°C under a nitrogen atmosphere. After being stirred overnight, the reaction solution was cautiously added to ice-water (150... 

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