Synthesis of 6-substituted 9-(dihydroxyalkyl) purines

5-Amino-6-chloro-4-dihydroxyalkylaminopyrimidines, which are cyclized to 6-chloro-9-(dihydroxyalkyl)purines, were obtained by the condensation of 5-amino-4,6-dichloropyrimidine with 2-amino-1,3-dihydroxypropane or with 2-amino-1,4-dihydroxybutane. The corresponding 6-hydroxy and 6-amino derivatives were obtained by replacement of the chlorine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 262–264, February, 1971.     

Synthesis and structure of 6-substituted 9-(2-ethoxy-1,3-dioxan-5-yl)purines

The reaction of 4-chloro-5-amino-6-(1,3-dihydroxy-2-propyl)aminopyrimidine with excess ethyl orthoformate gave a cyclic acetal, viz., 6-chloro-9-(2-ethoxy-1,3-dioxan-5-yl)purine, amination of which yielded 6-amino-9-(2-ethoxy-1,3-dioxan-5-yl)purine. The presence of two configurational isomers with a diaxial orientation of the purine ring and the ethoxy group in the trans isomer and an equatorial orientation of the ethoxy group in the cis isomer was established for these compounds by ¹H and ¹³C NMR and IR spectroscopy. The three-dimensional structure of trans-6-chloro-9-(2-ethoxy-1,3-dioxan-5-yl)purine was determined by an x-ray difraction study, and the trans-diaxial orientation of the purine ring and the ethoxy group was confirmed; it is shown that the dioxane ring is in an anti conformation relative to the purine ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 976–983, July, 1979.     

6-(2-Alkylimidazol-1-yl)purines undergo regiospecific glycosylation at N9

[reaction: see text] Regioselective control of glycosylation of purines at N9 (versus N7) has been a continuing challenge. We now report Lewis acid catalyzed regiospecific glycosylations of 6-(2-alkylimidazol-1-yl)purines at N9. The 6-(2-alkyl)imidazole moiety also functions as a versatile leaving group that can be replaced by nucleophiles (S(N)Ar) and aryl groups (Suzuki cross-coupling).     

Nucleoside analogs. I. A synthesis of 1,3-dihydroxy-2-(6-substituted-9-purinyl)cyclohexane

Biologically active 1,3-dihydroxy-2-(6-substituted-9-purinyl)cyclohexanes (VI-X) were prepared by a reaction between trans-2-amino-1,3-cyclohexanediol (I) and 4,6-dichloro-5-amino-pyrimidine (II), followed by cyclization and nucleophilic substitution. Compounds VI and VII showed a weak inhibitory effect against Xanthomonas oryzae, a pathogenic bacteria of leaf blight of rice plant.     

New nucleoside analogs from 2-amino-9-(beta-D-ribofuranosyl)purine

Four novel derivatives of 2-amino-9-(beta-D-ribofuranosyl)purine (1) were synthesised and fully characterised. When 1 was reacted with chloroacetaldehyde (a), 2-chloropropanal (b), bromomalonaldehyde (c) and a mixture of chloroacetaldehyde + malonaldehyde (d), 3-(beta-D-ribofuranosyl)-imidazo-[1,2a]purine (2), 3-(beta-D-ribofuranosyl)-5-methylimidazo-[1,2a]purine (3), 3-(beta-D-ribofuranosyl)-5-formylimidazo-[1,2a]purine (4) and 9-(beta-D-ribofuranosyl)-2-(3,5-diformyl-4-methyl-1,4-dihydro-1-pyridyl)purine (5) were formed, respectively. The products were isolated, purified by chromatography and characterised by MS, complete NMR assignment as well as fluorescence and UV spectroscopy. The yields of these reactions were moderate (14-20%). The fluorescence properties differed from those of the starting compound and the quantum yields were considerably lower.     

Synthesis of optically active 6-substituted 2-(aminomethyl)chromans

Three novel, optically active, 6-substituted 2-(aminomethyl)chromans were synthesized from readily available chroman 2-carboxylic acid precursors. These chroman-containing primary amines are useful building blocks for the synthesis of chroman-derived pharmaceutical agents.     

Synthesis of 9-(2-fluorobenzyl)-6-methylamino-9H-purine

Synthesis of 9-(2-fluorobenzyl)-6-methylamino-9H-purine ( 1 ) from nine different precursors is reported. Compound 1 was prepared by methylamination of 6-chloro-9-(2-fluorobenzyl)-9H-purine ( 4 ), by alkylation of 6-methylaminepurine ( 5 ) or form 9-(2-fluorobenzyl)-1-methyladeninium iodide ( 8 ) via the Dimroth rearrangement. Selective 2-step methylation of 6-aminopurine 6 was accomplished by hydride reduction of 6-formamidopurine 9 , 6-dimethylaminomethyleneaminopurine 10 or 6-phenylthiomethyl purine 11 to give 1. Compound 1 was also prepared by dethiation or reductive dechlorination of 2-methylthiopurine 16 or 8-chloropurine 19 , respectively, or by hydrolysis of 6-N-methylformamidopurine 12 , which was prepared from 6-dimethylaminopurine 13 by selective oxidation.     

Synthesis of diverse 6-(1,2-disubstituted ethyl)purine bases and nucleosides via 6-(oxiran-2-yl)purines

Dihydroxylation of 6-vinylpurines with t-BuOOH and OsO₄ gave 6-(1,2-dihydroxyethyl)purines 2, while the epoxidation with H₂WO₄ and t-BuOOH afforded 6-(oxiran-2-yl)purines 3. Oxirane ring-opening reactions of 3 with diverse nucleophiles gave a series of title 6-(1,2-disubstituted ethyl)purine bases and nucleosides, which were tested for cytostatic and antiviral activities.     

微波辐射快速合成2-(2＇-羟苯基)-5(6)取代苯并咪唑衍生物

苯并咪唑衍生物具有一定的抗病毒能力[1],一些苯并咪唑衍生物已用作农用抗植物病毒剂[2].一锅煮合成反应时间较长,产率中等[3,4].本文用取代邻苯二胺和水杨酸为原料,吡啶为溶剂,POCl3为催化剂,微波辐射法合成了标题化合物.     

Facile and efficient synthesis of 6-(hydroxymethyl)purines

[reaction: see text] A facile and efficient methodology of the synthesis of 6-(hydroxymethyl)purine derivatives (bases and nucleosides) was developed based on Pd-catalyzed cross-coupling reactions of 6-halopurines with acyloxymethylzinc iodides followed by deprotection. Several title compounds are inhibitors of adenosine deaminase and exert cytostatic activity.     

Chemosensor activity of 2-(anthracen-9-yl)-substituted imidazolidines and hexahydropyrimidines

A number of 2-(anthracen-9-yl)-substituted imidazolidines and hexahydropyrimidines were synthesized by reaction of N,N′-bis[aryl(hetaryl)methyl]ethylene-1,2-diamines and N,N′-bis[aryl(hetaryl)methyl]-propane-1,3-diamines with anthracene-9-carbaldehyde. The obtained compounds showed chemosensor activity toward Cd²⁺, Cu²⁺, and Hg²⁺ ions.     

Regiospecific N9 alkylation of 6-(heteroaryl)purines: shielding of N7 by a proximal heteroaryl C-H1

Purine alkylations have been plagued with formation of mixtures of N9 (usually desired), N7, and other regioisomers. We have developed methods for synthesis of 6-(azolyl)purine derivatives whose X-ray crystal structures show essentially coplanar conformations of the linked azole-purine rings. Such ring orientations position the C-H of the azole above N7 of the purine, which results in protection of N7 from alkylating agents. Treatment of 6-(2-butylimidazol-1-yl)-2-chloropurine (9) with sodium hydride in DMF followed by addition of ethyl iodide resulted in exclusive formation of 6-(2-butylimidazol-1-yl)-2-chloro-9-ethylpurine (10), whereas identical treatment of 2-chloro-6-(4,5-diphenylimidazol-1-yl)purine (11) produced a regioisomeric mixture 12/13 (N9/N7, approximately 5:1). The linked imidazole and purine rings are coplanar in 9 (the butyl side chain is extended away from the purine ring and C-H is over N7) but are rotated approximately 57 degrees in 11, and the more bulky azole substituent in 11 did not prevent formation of the minor N7 regioisomer 13. Access to various regioisomerically pure 9-alkylpurines is now readily available.     

Studies on hypotensive agents. Synthesis of 1-substituted 3-(2-chlorophenyl)-6-ethoxycarbonyl-5,7-dimethyl-2,4(1H,3H)-quinazoline diones.

3-(2-Chlorophenyl)-6-ethoxycarbonyl-5,7-dimethyl-2,4(1H,3H)-quinazoline dione was newly prepared. 1-Hydrogen atoms of the compound were variously substituted in order to test for their hypotensive activities on relaxing effects of the blood vessels. The compounds with 2-(1-pyrrolidinyl) ethyl, 2-(1-piperidinyl)ethyl, 3-(dimethylamino)propyl, and 3-(N-benzyl-N-methylamino)propyl moieties showed significant activity. The 2-(1-piperidinyl)ethyl compound possessed activity approximately 23 times more potent than papaverine, however, it was less potent than cinnarizine.     

Folic acid analogs. III. N-(2-[2-(2,4-diarnino-6-quinazolinyl)ethyl]benzoyl)-l-glutamic acid

A trideaza analog of aminopterin, N-(4[2-(2,4-diamino-6-quinazolinyl)ethyl]benzoyl)-L-glutamic acid, was prepared by a Wittig condensation of 2,4-diaminoquinazoline-6-carboxaldehyde and [P-(N-[1,3-bis(ethoxycarbonyl)propan-1-yl]aminocarbonyl)phenylmethyl]triphenylphosphonium bromide followed by catalytic reduction and mild hydrolysis. This compound was found to have confirmed inhibitory activity against leukemia L1210 in mice.     

Synthesis of 6-Methyl-4-(1-methyl-2-buten-1-yl)-2-(2-cyclohexen-1-yl)- and 6-Methyl-4-(1-methyl-2-buten-1-yl)-2-(1-cyclohexen-1-yl)anilines

Alkenylation of 6-methyl-2-(2-cyclohexen-1-yl)- and 2-(1-cyclohexen-1-yl)anilines with piperylene in the presence of AlCl₃ and transformation of the resulting cyclohexenylanilines into carbazole structures were studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 441–443.Original Russian Text Copyright © 2005 by Gataullin, Ishberdina, Sotnikov, Abdrakhmanov.     

Synthesis and optical behaviors of 2-(9-phenanthrenyl)-, 2-(9-anthryl)-, and 2-(1-pyrenyl)-1-alkylimidazole homologues

Eight 2-(9-phenanthrenyl)-, 2-(9-anthryl)- and 2-(1-pyrenyl)-1-alkyl-benzimidazole compounds, three 2-(9-anthryl)-1-alkylphenanthroimidazole compounds and five 4,5-diphenyl-1-alkyl-2-(9-anthryl)imidazole compounds were synthesized by alkylation reactions of the corresponding benzimidazole, phenanthroimidazole or imidazole compounds. 2-(10-Bromo-9-anthryl)-1-alkyl-benzimidazole compounds were prepared by bromination reaction of 2-(9-anthryl)-1-alkylbenzimidazole compounds. All the synthesized compounds were characterized by elemental analysis, ¹H NMR, ¹³C NMR, MS or HRMS; their absorption coefficients (), maximum absorption λ_amax, fluorescence emission maximum λ_em, Stokes shifts and fluorescence quantum yields (Φ_F) in ethyl acetate were determined; their fluorescent lifetimes (T₁ and T₂) were measured in ethyl acetate and in solid state, respectively. The crystal structure of 2-(9-anthryl)-1-n-butyl-4,5-diphenylimidazole (12a) was determined to be triclinic, space group P-1 types, using single crystal X-ray crystallography technique. The results showed that these compounds exhibited moderate fluorescence-emission abilities and higher solubility in most organic solvents than their corresponding starting materials. The relationships between the optical behaviors and structures for these compounds were discussed.