2009-52-1Relevant academic research and scientific papers
Molecular and crystal structures of dialkylated adenines (N6,N9-Me2Ade, N3,N6-MeBnAde) and cytosines (N1,N4-Me2Cyt)
Krüger, Thomas,Wagner, Christoph,Bruhn, Clemens,Lis, Tadeusz,Steinborn, Dirk
, p. 110 - 114 (2008)
N6,N9-Dimethyladenine (N6,N9-Me2Ade, 1) and N1,N4-dimethylcytosine (N1,N4-Me2Cyt, 3) were obtained by conventional methods, whereas the reaction of N6-benzyladenine with MeI/NaOH resulted in the formation of N3,N6-MeBnAde (2a) and N6,N9-BnMeAde (2b). All compounds were fully characterized by microanalysis, NMR spectroscopy (1H, 13C) and 1, 2a·2MeOH and 3 also by single-crystal X-ray diffraction analyses. In single-crystals of 1, obtained from THF solutions, twofold N6-H···N7′ hydrogen-bonded dimeric units (N6,N9-Me2Ade)2 (AA12 type according to Jeffrey and Saenger, 1991) were found. This proved to be another modification than that obtained by crystallization N6,N9-Me2Ade from MeOH/PhCl (Sternglanz, 1978). Crystals of 2a·2MeOH exhibited an analogous hydrogen bond pattern as found in 1. The shorter N6···N7′ distance in 2a·2MeOH (2.932(2) A?) indicates slightly stronger hydrogen bonds than in 1 (3.078(3) A?). Crystals of 3 are built up from centrosymmetric dimers (N1,N4-Me2Cyt)2 having a twofold N4-H···N3′ hydrogen bond, thus exhibiting the CC32 hydrogen bond pattern. The hydrogen bonding patterns in the dialkylated nucleobase derivatives are discussed in terms of those found in crystals of the less substituted nucleobases N9-MeAde and Cyt/N1-MeCyt, respectively.
Reaction of 9-substituted 1-aminoadenine with hydrazine
Asano, Shoji,Itano, Keiji,Yamagata, Yuriko,Kohda, Kohfuku
, p. 1115 - 1121 (2007/10/03)
Reaction of 9-substituted (methyl or benzyl) 1-aminoadenines 1 with hydrazine afforded 9-substituted 6-hydrazinopurines 2 and 1-substituted 5-amino-4-(4-amino-1,2,4-triazol-3-yl)imidazole (4). The product ratio of 2 to 4 rose with increasing amounts of me
Synthesis and Properties of Purinophanes: Relationship between the Magnitude of Hypochromism and Stacking Geometry of Purine Rings
Seyama, F.,Akahori, K.,Sakata, Y.,Misumi, S.,Aida, M.,Nagata, C.
, p. 2192 - 2201 (2007/10/02)
Twelve purinophanes 1-12, in which two purine rings are fixed with different modes of stacking by two or three polymethylene chains, have been prepared by either stepwise introduction of the linking chains or quasi-dimerization of disubstituted purine der
Purines. XXVI. The Dimroth Rearrangement of 9-Substituted 1-Methyladenines: Accelerating Effect of a β-D-Ribofuranosyl Group at the 9-Position
Fujii, Tozo,Saito, Tohru
, p. 3635 - 3644 (2007/10/02)
The reaction rates in the Dimroth rearrangements of 9-substituted 1-methyladenines (5a-i) were measured in H2O at various pH's and ionic strength 1.0 at 40 deg C.In all cases, attack of hydroxide ion on the protonated species of 5 at the 2-position was fa
METHYLATION OF ADENINE AND THERMAL TRANSFORMATIONS OF ITS N-METHYL DERIVATIVES
Muravich-Aleksandr, Kh. L.,Pernikoza, V. G.,Girshovich, M. Z.,Ragozina, T. N.
, p. 2094 - 2099 (2007/10/02)
The methylation of adenine with methyl iodide in DMFA at 20-30 deg C gives the products from kinetically controlled reactions, i.e., 3-methyl- and 1-methyl-adeninium salts, and the reaction at 100 deg C gives 3-methyl- and 1,9-dimethyladeninium salts.The reaction mixture formed under more drastic conditions (150 deg C) consists mainly of thermodynamically stable 3,7- and 1,9-dimethyladeninium iodides.The transformation from the 1- and 3-methyladeninium iodides to the thermodynamically stable 9-methyladenine is only observed during fusion.
Purines. XXII. Methylation of 1-, 3-, 7-, 9-, and N6-Methyladenines Bearing a Methoxyl Group at the N6-Position: A Synthesis of 7,9-Dimethyladenine
Fujii, Tozo,Itaya, Taisuke,Tanaka, Fumiko,Saito, Tohru,Mohri, Kazuto,Yamamoto, Kiyomi
, p. 3149 - 3159 (2007/10/02)
In order to investigate the effect of the N6-methoxy group on the site of methylation, N6-methyl- (27), 1-methyl- (17), 3-methyl- (11), 7-methyl- (7), and 9-methyl-N6-methoxyadenine (2) were methylated with an excess of MeI in AcNMe2.The products isolated were the 3-methylated product 12*HClO4 (67percent yield) and 9-methylated product 3 (18percent yield) from 27; 3-methylated product 15 (X=I) (44percent) and 9-methylated product 18*HClO4 (38percent) from 17; 15 (X=I) (40percent) and 12*HClO4 (36percent) from 11; 9-methylated product 5 (X=I) (36percent) and 3-methylated product 8 (44percent) from 7; 5 (X=I) (59percent) and 3*HI (24percent) from 2.Further methylation of 18 in a similar manner was found to give N6-methoxy-1,7,9-trimethyladeninium iodide (33: X=I) in 92percent yield.A similar methylation of the betaine 32, generated from 5 (X=I) by treatment with 1,8-diazabicycloundec-7-ene (DBU), also produced 33 (X=I) in fair yield.The 7,9-dimethyl derivative 5 (X=I) thus obtained was converted into the perchlorate 5 (X=ClO4), and hydrogenolysis of 5 (X=ClO4) using Pd-C and hydrogen furnished hitherto unknown 7,9-dimethyladeninium perchlorate (6: X=ClO4) in good yield.The substrates 11 and 27 used for the methylation study were prepared in 87 and 86percent yields from 3-methyl-6-methylthiopurine (10) and 6-chloropurine (26) by amination with methoxyamine and N,O-dimethylhydroxylamine, respectively.For the synthesis of the substrate 17, 1-methoxyadenosine (25) was methylated to give the N6-methyl derivative 23.Treatment of 23 with hot water and hydrolysis of the resulting isomer 21 with 98percent formic acid afforded the desired compound 17. Keywords ----- regioselectivity in methylation; effect of N6-methoxy group; N6-methoxy-N-methyladenine; N6-methoxy-Nx,Ny-dimethyladenine; N6-methoxy-trimethyladenine; 1,3-dimethyladenine derivative; 7,9-dimethyladenine; catalytic hydrogenolysis of N-O bond; Dimroth rearrangement; hydrolysis
