کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1410591 1501873 2008 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Molecular and crystal structures of dialkylated adenines (N6,N9-Me2Ade, N3,N6-MeBnAde) and cytosines (N1,N4-Me2Cyt)
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Molecular and crystal structures of dialkylated adenines (N6,N9-Me2Ade, N3,N6-MeBnAde) and cytosines (N1,N4-Me2Cyt)
چکیده انگلیسی

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) Å) indicates slightly stronger hydrogen bonds than in 1 (3.078(3) Å). 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.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure - Volume 891, Issues 1–3, 26 November 2008, Pages 110–114
نویسندگان
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