Adenine hydrochloride

The determination of the structure of adenine hydrochloride (see Volume 2, Section IV,K, of article IV by Katritzky and Lagowski) is an example of extremely accurate X-ray crystallography whereby the positions of individual hydrogen atoms were located. An example of the deduction of structure from bond lengths between heavy atoms is provided by Penfold s investigation of pyrid-2-thione. ... 

After inconclusive early work,-" structure 218 was demonstrated for adenine hydrochloride using X-ray diffraction (cf. also reference 256) and was later supported by nuclear magnetic resonance evidence. Four possible structures have been advanced for guanine... 

The adenine radical cation was observed in a single crystal of adenine hydrochloride hemihydrate [43]. In this crystal, the adenine is protonated at Nl. After electron loss, the molecule deprotonates at Nl, giving Ade(Nl -l-H, Nl-H). This produces a radical that is structurally equivalent to the cation of the neutral adenine molecule with spin density on C8 and N6 [p(C8) = 0.17 and p(N6) = 0.25]. The adenine radical cation is strongly acidic (pi a< 1) [22]. This strong driving force makes the reaction independent of environmental conditions. In single crystals of adenosine [42] and anhydrous deoxyadenosine [44], the N6 deprotonated cation [Ade(N6-H) ] is observed which is characterized by p(C8) = 0.16 and p(N6) = 0.42. The experimental isotropic hyperfine couplings are N6-H = 33.9 MHz and C8-H = 12.4 MHz. 

As an example of the use of single-crystal photographs for identification, vitamin B4 was shown by Bernal and Crowfoot (1933 b) to be identical with adenine hydrochloride. The extensive survey of the crystallography of substances of the sterol group by Bernal, Crowfoot, and Fankuchen (1940) gives a vast amount of information on these crystals, including unit cell dimensions this paper also contains a discussion of the identification problems in this group. 

Fig. S--9.—A drawing showing the dimensions cf the moiecule of adenine as determined by x-iay analysis or ciystals of adenine hydrochloride bemihyd rate.

EHNA Erythro-9-(2-hydroxy-3-nonyl)adenine hydrochloride... 

ADENCH02. Adenine hydrochloride hemihydrate [2(C3H6N3+), 2(Cl-), H2OJ. Kistenmacher TJ, Shigematsu T (1974) Acta Crystallogr, Sect B 30 166 ADENIC. N-(3-(Aden-9-yl)propyl)-3-carbamoylpyridinium bromide hydrobromide dihydrate [C14H17NtO++, 2(Br-), 2(H20)]. Johnson PL, Frank JK, Paul IC (1973) J Am Chem Soc 95 5377... 

Bond length (angle) Purine" Adenine hydrochloride hemihydrate Guanine hydrochloride dihydrate" Hypoxanthine hydrochloride monohydrate°... 

T. J. Kistenmacher and T. Shigematsu, Acta Crystallogr., Sect. B, 30, 166 (1974). Adenine Hydrochloride Hemihydrate Three-Dimensional Data and Refinement. 

Figure 32. Adenine-stacks after (136, 137j. (a) RNA (b) A-DNA (c) B-DNA (d) C-DNA (e) de-oxyadenosine-monohydrate and adenosine-5 -phosphate (f) adenosine-3 -phosphate (g) adenine-hydrochloride and 9-methyl-adenine-dihydrobromide (h/k) 9-methyl-adenine (i)(A). ...

Fig. 5. A drawing showing the dimensions of the molecule of adenine as determined by x-ray analysis of crystals of adenine hydrochloride hemihydrate.

The dimensions of the molecules of two purines are given in Figs. 5 and 6. Figure 5 is from the investigation of adenine hydrochloride hemi-hydrate by Cochran (11), following an earlier study by Broomhead (12), and Fig. 6 from that of guanine hydrochloride monohydrate (13), by Broomhead. 

Fig. 12. A drawing of the crystal structure of adenine hydrochloride hemi-hydrate. Hydrogen bonds are indicated by dashed lines. The dimensions were calculated from the coordinates given by Cochran (11).

CsHgClNa, 2-Amino-6-chloro-4-methylpyrimidine, 11, 718 CsHgClNs 0.5 H2O, Adenine hydrochloride hemihydrate, 40B, 379 CsHgClaHgNs 1.5 HjO, Adeninium trichloromercurate(II) sesquihyd-rate, 41B, 464... 

C10H13N5, N -(A -Isopentenyl)adeninej 38B, 427 C10H13N5, 6-Amino-3-dimethylallylpurine, 43B, 521 Cl0H14CI2N1oO, Adenine hydrochloride hemihydrate, 11, 723 15, 492 CioHi N,05, cis syn 6-Methyluracil photodimer monohydrate, 37B, 227 Cl0H14N,05, 5a-Hydroxy-6,4 -(5 -methylpyrimidin-2 -one)-dihydrothy-mine monohydrate, 34B, 240... 

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