Further Studies on the Alkylation of Purines<sup>1</sup>

Hewson, Kathleen; Clayton, S. J.; Thomas, H. Jeanette

doi:10.1021/jo01345a030

Cited by 47 publications

(19 citation statements)

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“…lt is noteworthy, however, that in 9-methyladenine the residual charges on N ( I ) , N(3), and N ( 7 ) a r e -0.29, -0.24, and -0. (2) 2.14(2) 153 (2) N(6) H(62) N ( I ) 3.094 (2) 2.22 (2) 167 (2) than in 8-azaadenosine or formycin and is comparable to the N(6) atom in 6-azapyrimidines." W e are currently attempting to isolate the cation of 7-methyWazaadenine, and also metal complexes of this ligand, to investigate further the relative basicities of the ring nitrogen atoms.…”

Section: Resultsmentioning

confidence: 98%

“…T h e angles in the triazole portion are in the ranges tabulated by Purnell and Hodgson4' for substituted 8-azapurines, provided again that allowance is made for the N(7) rather than N(9) substitution here. Thus, for example, in 8 -a~a a d e n o s i n e~~ the substituent is at N (9) and the angle at N ( 9 ) is larger [109.8 (2)"] than that a t N ( 7 ) [ 108.6 (2)"]; in the present case, therefore, it is to be expected that the angle at N(7) [ 109.4 ( I ) " ] is larger than that a t N ( 9 ) (3) 1.454 (2) the observed range. All bond angles are tabulated in Table 1v.…”

Section: Resultsmentioning

confidence: 99%

“…Strong hydrogen bonds involving the NH and C=O functions of the y-lactam ring, present in all other cytochalasin structures, may be important in binding to the toxin's site of action. The toxin crystallizes from diethyl ether as stocky prisms with the monoclinic space group P21 and cell constants a = 7.338 ( 2 ) A, b = 13.053 ( 6 ) This structural and N M R study was undertaken to unambiguously determine the identity of the new toxin and to examine its relationship with the known cytochalasins.…”

Section: Introductionmentioning

confidence: 99%

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Structure of 7-methyl-8-azaadenine. A crystallographic and molecular orbital study

Shoemaker¹,

Hodgson²

1977

J. Am. Chem. Soc.

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The crystal and molecular structure of 7-methyl-8-azaadenine (6-amino-7-niethyl-8-azapurine), CzH6N6, has been determined from three-dimensional x-ray counter data obtained using Mo Ka radiation. The material crystallizes in the orthorhombic space group Pbcn with eight formula units in a cell of dimensions a = 7.578 (2), b = 13.328 (3), and c = 12.566 ( 4 ) A. The observed and calculated densities are 1 .57 (3) and 1.572 g cmW3, respectively. The structure has been refined to a final value of the conventional R factor (on F ) of 0.041 using 1 I25 independent intensities. The azapurine ring is approximately planar. w i t h no atom deviating from the least-squares plane by more than 0.03 A. There is considerable intermolecular hydrogen bonding in the crystals, involving N ( I ) and N(3) as acceptors and the amino group as the donor. I t is noteworthy that neither N(8) nor N ( 9 ) participate in hydrogen bonding. A C N D 0 / 2 molecular orbital calculation provides a n explanation for this observation b j showing that the residual negative charges on K( I ) and N(3) (-0.27 and -0.23 electron, respectively) are much larger than those on N(8) and N(9) (-0.01 and -0.16 electron, respectively).T h e 8-azapurines ( I ) , which a r e purines (11) in which the imidazole ring has been changed t o a 1,2,3-triazole, a r e of H

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structure of 7-methyl-8-azaadenine. A crystallographic and molecular orbital study

Shoemaker¹,

Hodgson²

1977

J. Am. Chem. Soc.

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“…These imidazoles were presumably formed from the cyclonucleoside of inosine. Montgomery and his coworkers (174,206) also found that derivatives of aminoimidazolecarboxamides were formed from quaternary salts under mild conditions as follows: CVIIa and LXXXIIg from 1,3-dibenzyland 1,3,7-tribenzylhypoxanthinium bromides, respectively ; and CVIIc from 3,9-dibenzyl-6-(dimethylamino)purinium bromide (CIVd). Compounds CVIIb and CVIId were prepared from CVIIa and CVIIc, respectively.…”

Section: Hn=c-nhmentioning

confidence: 99%

“…Further, mild basic treatment hydrolyzed the amidine and the formamide groups, yielding an AIC ribonucleoside analog (CVIa). Michelson (204) mentioned the formation of a similar amidine (CVb, Rl = H) from the cyclonucleoside of 2',3'-isopropylideneadenosine (CIVb); Montgomery et al(174) observed the formation of an N-benzyl-AIC ribonucleoside analog (CVIb) by facile ring cleavage of the isopropylidene-protected cyclonucleoside of 1benzylinosine, a hypoxanthinium salt. Kusashio and Yoshikawa (205) isolated small amounts of CVIc and carbonitrile analogs of CVIc (R1 = CHO and H) during studies of the phosphorylation of 2',3'-0isopropylideneinosine with phosphorus oxychloride…”

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confidence: 99%