bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of Fused Tetracyclic Quinazolinones by Combinations of Aza‐Wittig Methodologies and CuI‐Catalysed Heteroarylation Processes
Authors: Bleda Juan Antonio , Fresneda Pilar M. , Orenes Raul , Molina Pedro 
Published: April 2009

AbstractA number of linear quinazolinones fused to five‐membered rings – benzimidazo[2,1‐b]quinazolinones 8 and benzothiazolo[2,3‐b]quinazolinones 10 – have been prepared from iminophosphoranes 4, derived from N‐substituted o‐azidobenzamides by a combination of the aza‐Wittig methodology and CuI‐catalysed heteroarylation. The presence of a nitrogen functionality in the N‐aryl substituent of 4 promotes heterocyclization after an aza‐Wittig reaction/reductive process, either across the 2‐position, to afford quinazolino[2,1‐b]quinazolinones 11–14, or across the 4‐position, to afford the benzimidazo[1,2‐c]quinazoline 16 from the initially formed 3H‐quinazolin‐4‐one. When an acetyl group is present in the N‐aryl substituent of 4, aza‐Wittig reactions with isocyanates lead directly to 4‐methylene‐4H‐3,1‐benzoxazines 18; this transformation involves the initial formation of a carbodiimide, which undergoes ring‐closure through the enol form of the carboxamide group and eventually an unprecedented iminobenzoxazine/methylenebenzoxazine rearrangement. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Autoregressive models for maxima and their applications to CH4and N2O
Authors: Toulemonde Gwladys , Guillou Armelle , Naveau Philippe , Vrac Mathieu , Chevallier Frederic 
Published: April 2009

AbstractRecordings of daily, weekly, or yearly maxima in environmental time series are classically fitted by the generalized extreme value (GEV) distribution that originates from the well‐established extreme value theory (EVT). One special case of such GEV distribution is the Gumbel family which corresponds to the modeling of maxima stemming from light‐tailed distributions. To capture temporal dependencies, linear autoregressive (AR) processes offer a simple and elegant framework. Our objective is to extend linear AR models in such a way that they handle Gumbel distributed maxima. To reach this goal, we take advantage of the stability of Gumbel random variables when added to the logarithm of a positive α‐stable random variable. This allows us to propose a linear Gumbel distributed AR model whose main theoretical properties are derived. For the atmospheric scientist, this link between linear AR processes and EVT widens the statistical treatment of extreme environmental recordings in which temporal dependencies are present. For example, our model is fitted to daily and weekly maxima of methane (CH4) and daily maxima of nitrous oxide (N2O) measured in Gif‐sur‐Yvette (France). Simulation results are also presented in order to assess the quality of our parameter estimations for finite samples. Copyright © 2009 John Wiley & Sons, Ltd.
Functional connectivity in the default network during resting state is preserved in a vegetative but not in a brain dead patient
Authors: Boly M. , Tshibanda L. , Vanhaudenhuyse A. , Noirhomme Q. , Schnakers C. , Ledoux D. , Boveroux P. , Garweg C. , Lambermont B. , Phillips C. , Luxen A. , Moonen G. , Bassetti C. , Maquet P. , Laureys S. 
Published: April 2009

AbstractRecent studies on spontaneous fluctuations in the functional MRI blood oxygen level‐dependent (BOLD) signal in awake healthy subjects showed the presence of coherent fluctuations among functionally defined neuroanatomical networks. However, the functional significance of these spontaneous BOLD fluctuations remains poorly understood. By means of 3 T functional MRI, we demonstrate absent cortico‐thalamic BOLD functional connectivity (i.e. between posterior cingulate/precuneal cortex and medial thalamus), but preserved cortico‐cortical connectivity within the default network in a case of vegetative state (VS) studied 2.5 years following cardio‐respiratory arrest, as documented by extensive behavioral and paraclinical assessments. In the VS patient, as in age‐matched controls, anticorrelations could also be observed between posterior cingulate/precuneus and a previously identified task‐positive cortical network. Both correlations and anticorrelations were significantly reduced in VS as compared to controls. A similar approach in a brain dead patient did not show any such long‐distance functional connectivity. We conclude that some slow coherent BOLD fluctuations previously identified in healthy awake human brain can be found in alive but unaware patients, and are thus unlikely to be uniquely due to ongoing modifications of conscious thoughts. Future studies are needed to give a full characterization of default network connectivity in the VS patients population. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Inhibition of mammalian target of rapamycin signaling potentiates the effects of all‐trans retinoic acid to induce growth arrest and differentiation of human acute myelogenous leukemia cells
Authors: Nishioka Chie , Ikezoe Takayuki , Yang Jing , Gery Sigal , Koeffler H. Phillip , Yokoyama Akihito 
Published: April 2009

AbstractOur study explored the drug interaction of all‐trans retinoic acid (ATRA) and RAD001 (everolimus), the inhibitor of mammalian target of rapamycin complex 1 (mTORC1), in acute myelogenous leukemia (AML) NB4 and HL60 cells. RAD001 (10 nM) significantly enhanced the ATRA‐induced growth arrest and differentiation of these cells, as measured by colony‐forming assay and cell cycle analysis, and expression of CD11b cell surface antigen and nitroblue tetrazolium reduction, respectively. ATRA (0.1–1 μM) upregulated levels of RTP801, a negative regulator of mTORC1, and inhibited mTORC1 signaling as assessed by measurement of the levels of p‐p70S6K and p‐4E‐BP1 in HL60 and NB4 cells. ATRA (0.1–1 μM) in combination with RAD001 (10 nM) strikingly downregulated the levels of p‐70S6K and p‐4E‐BP1 without affecting the total amount of these proteins. Notably, RAD001 (10 nM) significantly augmented ATRA‐induced expression of CCAAT/enhancer‐binding protein ε (C/EBPε) and p27kip1 and downregulated levels of c‐Myc in these cells. Furthermore, RAD001 (5 mg/kg) enhanced the ability of ATRA (10 mg/kg) to inhibit the proliferation of HL60 cells growing as tumor xenografts in immune‐deficient nude mice. Taken together, concomitant blockade of the RA and mTORC1 signaling may be a promising treatment strategy for individuals with AML. © 2009 UICC
HLA‐DR expression is associated with better prognosis in sporadic Australian clinicopathological Stage C colorectal cancers
Authors: Walsh Michael D. , Dent Owen F. , Young Joanne P. , Wright Caroline M. , Barker Melissa A. , Leggett Barbara A. , Bokey Les , Chapuis Pierre H. , Jass Jeremy R. , Macdonald Graeme A. 
Published: April 2009

AbstractPredicting patient outcome for colorectal carcinoma (CRC) with lymph node but not distant metastases remains challenging. Various prognostic markers have been identified including microsatellite instability (MSI) and possibly expression of the MHC Class II protein, HLA‐DR. About 15% of sporadic CRC exhibits MSI associated with methylation of the DNA mismatch repair gene hMLH1 promoter. In addition, a significant proportion of unselected CRC demonstrates expression of HLA‐DR. We sought to examine the relationship between HLA‐DR expression, MSI status and prognosis in sporadic Australian Clinicopathological (ACP) Stage C CRC. Two hundred seventy consecutive patients with sporadic ACP Stage C CRC were treated at Concord Repatriation General Hospital between 1986 and 1992. None of these patients received adjuvant chemotherapy and all were followed for a minimum of 5 years or until death. DNA was extracted from paraffin sections and MSI status determined by PCR. HLA‐DR expression was determined immunohistochemically using an antibody against the HLA‐DR α chain. MSI status could be assigned in 235 cases: 176 CRCs (74.9%) were microsatellite stable, whereas 23 (9.8%) had high levels of MSI (MSI‐H) and 36 (15.3%) had low levels of MSI (MSI‐L). HLA‐DR expression by CRC cells was seen in 148 (60.1%) cases and correlated with the presence of tumor‐infiltrating lymphocytes (p = 0.0005) and peritumoral lymphocytes (p = 0.003), but not other clinicopathological features or MSI status. HLA‐DR‐positive CRCs were strongly associated with better patient outcome (p < 0.0001). © 2009 UICC
Testing for cointegration using the Johansen approach: are we using the correct critical values?
Authors: Turner Paul 
Published: April 2009

AbstractThis paper presents Monte Carlo simulations for the Johansen cointegration test which indicate that the critical values applied in a number of econometrics software packages are inappropriate. This is due to confusion in the specification of the deterministic terms included in the vector error correction model (VECM). The result is a tendency to reject the null of no cointegration too often. Copyright © 2009 John Wiley & Sons, Ltd.
Are dispersal‐dependent behavioral traits produced by phenotypic plasticity?
Authors: Meylan Sandrine , de Fraipont Michèle , Aragon Pedro , Vercken Elodie , Clobert Jean 
Published: April 2009

AbstractDispersal is a common response to deteriorating conditions such as intense competition, food limitation, predation or parasitism. Although it provides obvious advantages, dispersal is often assumed to be costly. Selection is therefore likely to have acted to decrease these costs, and indeed several studies demonstrated that dispersers and philopatric individuals differ in their morphology, physiology and/or behavior. Using the common lizard (Lacerta vivipara) as our model system, we examined the contribution of phenotypic plasticity to the establishment of dispersal‐dependent behavioral traits. We used a reciprocal transplant experiment in which conditions at the maternal site of origin, during offspring development in utero, and at the release site were manipulated. We then compared activity, social interactions and foraging behavior between individuals that stayed philopatric and those that dispersed. Most behavioral traits were also measured at birth and after the dispersal phase.This study demonstrates that (a) 10 months after the dispersal phase, there were still marked behavioral differences between dispersing and philopatric individuals, (b) the reaction when confronted to another individual was also dispersal‐status dependent, a result which strongly suggests that individuals are able to recognize the dispersal status of same‐age conspecifics and (c) none of the behavioral characteristics were found to be dependent on the environmental conditions (maternal and natal environment) indicating a lack of phenotypic plasticity in the building of the dispersal‐dependent behavioral traits examined. J. Exp. Zool. 311A:377–388, 2009. © 2009 Wiley‐Liss, Inc.
The synthesis and chemistry of a bis‐pyrazolinylketone and the structure determination
Authors: Lin Tay‐Yean , Cromwell Norman H. , Kingsbury Charles A. 
Published: April 2009

AbstractThe synthesis and spectral characteristics of a bis‐spiro compound: 2,6‐bis(4‐phenyl‐3‐δ1‐pyrazolinyl)cyclo‐hexanone are reported. Unlike literature reports, this particular δ1‐pyrazoline does not readily rearrange to the 2 isomer on heating. Pyrolysis gives 2,6‐bis(α‐methylbenzylidene)cyclohexanone. A monopyrazolinylket‐one was also isolated which is most likely an intermediate in the bis‐denitrogenation. A mechanism for the denitrogenation‐rearrangement is proposed.
Synthesis of heterocyclic compounds. XXXIX. Synthesis of 5‐cyano‐2‐phenyl‐4‐thioxo‐3,4‐dihydropyrimidines
Authors: Lorente A. , García Navío J. L. , Vaquero J. J. , Soto J. L. 
Published: April 2009

AbstractThe reaction of thiobenzamide with 3‐alkoxy‐3‐aryl(or alkyl)‐2‐cyanopropenenitriles 1 and sodium 2‐propoxide in 2‐propanol afforded after acidic treatment 6‐aryl(or alkyl)‐5‐cyano‐2‐phenyl‐4‐thioxo‐3,4‐dihydropyrimidines 3 through formation of the 3‐aryl(or alkyl)‐2‐cyano‐3‐thiobenzamidopropenenitrile 2 that has been isolated in one case (2a, R1 = Ph).
Synthesis of 7‐oxopyrrolo[3,2‐B]pyridine‐6‐carboxylic acid derivatives as potential antimicrobial agents
Authors: Bayomi Said M. , Price Kenneth E. , Sowell J. Walter 
Published: April 2009

AbstractA route for the synthesis of various derivatives of 7‐oxopyrrolo[3,2‐b]pyridine‐6‐carboxylic acid from 2‐methyl‐3‐carbomethoxy‐4‐aminopyrrole is reported.
Synthesis of 4,10‐dihydro‐4,10‐dioxo‐1H[1]benzothiopyrano[3,2‐B]pyridine and 7‐oxo‐7,13‐dihydro[1]benzothiopyrano[2,3‐b]‐1,5‐benzodiazepine
Authors: Nakazumi Hiroyuki , Endo Takashi , Nakaue Toshiyuki , Kitao Teijiro 
Published: April 2009

Abstract3‐Amino‐4H‐1‐benzothiopyran‐4‐one (3‐aminothiochromone) was easily prepared by reaction of 3‐bromo‐thiochromen‐4‐one with sodium azide in methanol‐water. Condensation of 3‐aminothiochromone with diethyl ethoxymethylenemalonate and with dimethyl acetylenedicarboxylate gave intermediates, which were thermally cyclized to give 4,10‐dihydro‐4,10‐dioxo‐1H[1]benzothiopyrano[3,2‐b]pyridinecarboxylates. 3‐Formyl‐thiochromone was condensed with o‐phenylenediamine to give 7‐oxo‐7,13‐dihydro[1]benzothiopyrano[2,3‐b]‐1,5‐benzodiazepine.
Synthesis using pyridinium anhydrobases, preparation of indolizine derivatives
Authors: Molina P. , Fresneda P. M. , Lájara M. C. 
Published: April 2009

AbstractA number of derivatives of indolizine ring system have been prepared from 1‐substituted 4,6‐diphenyl‐2‐phenacylidene‐1,2‐dihydropyridines either by metallation with LDA or acylation and further basic treatment. Similarly, I‐arylmethyl‐4,6‐diphenyl‐2‐dicyanomethylene‐1,2‐dihydropyridines by action of LDA undergo cyclization to the corresponding 2‐amino‐1‐cyano‐3‐aryl indolizines.
Synthesis of 2‐(2‐imidazolinyl) substituted 2,3‐dihydro‐4H‐1,4‐benzothiazine and 3,4‐dihydro‐2H‐1,4‐benzoxazines
Authors: Butler Richard C. M. , Chapleo Christopher B. , Myers Peter L. , Welbourn Anthony P. 
Published: April 2009

AbstractAn investigation into the synthesis of benzoxazine, benzoxathiane and benzothiazine derivatives of 2‐(2‐imidazolinyl)‐1,4‐benzodioxane has been carried out.
Novel nucleophilic substitution of alkyl bromo‐2(1H)‐pyridones
Authors: Pessolano A. A. , Witzel B. E. , Graham P. M. , Clark R. L. , Jones H. , Dorn C. P. , Carty J. , Shen T. Y. 
Published: April 2009

AbstractNucleophilic substitution of certain alkyl bromo‐2(1H)‐pyridones gave some unexpected products where the alkyl group is substituted and the ring bromine is replaced by hydrogen. The expected ring substituted product is also formed, but only as the minor product in most cases. Many reactions are cited with various nucleophiles, and a plausible mechanism is also presented.
E‐ and Z‐isomerism of 2‐acetylthiophene oximes
Authors: Conde Santiago , Corral Carlos , Lissavetzky Jaime 
Published: April 2009

AbstractA study on the oximation of a number of 2‐acetylthiophenes in order to ascertain the validity of contradictory results previously described is reported. The fact that the steric hindrance is smaller in 2‐acetylthiophenes unsubstituted at position‐3 than in acetylbenzenes allows in these cases the formation of Z oximes, which even can predominate on the E oximes in the case of a + M substitution at position‐5. In the paper is also shown that the E/Z ratio of 2‐acetylthiophene oximes can be deduced from the 1H‐nmr spectrum of the crude oxime mixture.
Substituted 2‐Pyrones and 5,6‐Dihydropyrones
Authors: Groutas William C. , Huang Tien L. , Stanga Michael A. , Brubaker Michael J. , Moi Min K. 
Published: April 2009

AbstractA series of substituted 2‐pyrones and 5,6‐dihydropyrones have been synthesized and investigated for their inhibitory activity toward human leukocyte elastase, procine pancreatic elastase and chymotrypsin.
Electron impact induced fragmentation of some 7‐(o‐ and p‐R‐benzylidene)‐3‐(o‐ and p‐R‐phenyl)‐3,3a,4,5,6,7‐hexahydro‐2H‐indazoles. I
Authors: Cortés E. , Martínez R. , Arzacoya E. 
Published: April 2009

AbstractThe mass spectral fragmentation patterns of ten 7‐(o‐ and p‐R‐benzylidene)‐3‐(o‐ and p‐R‐phenyl)‐3,3a,4,5,6,7‐hexahydro‐2H‐indazoles, I, obtained by electron impact have been studied. All the spectra analyzed contain molecular ions and the principal fragmentation routes take place either from the molecular ion, or from (M+‐1) ion. Likewise, our investigation of the mass spectra of these compounds revealed interesting relationships between the substitution pattern in the framework of I and the fragmenation pathways.
Purine analog inhibitors of xanthine oxidase ‐ structure activity relationships and proposed binding of the molybdenum cofactor
Authors: Robins Roland K. , Revankar Ganapathi R. , O'Brien Darrell E. , Springer Robert H. , Albert Thomas Novinson Anthony , Senga Keitaro , Miller Jon P. , Streeter David G. 
Published: April 2009

AbstractA number of new hypoxanthine analogs have been prepared as substrate inhibitors of xanthine oxidase. Most noteworthy inhibitory new hypoxanthine analogs are 3‐(m‐tolyl)pyrazolo[1,5‐a]pyrimidin‐7‐one (47), ID50 0.06 μM and 3‐phenylpyrazolo[1,5‐a]pyrimidin‐7‐one (46), ID50 0.40 μM. 5‐(p‐Chlorophenyl)pyrazolo[1,5‐a]pyrimidin‐7‐one (63) and the corresponding 5‐nitrophenyl derivative 64 exhibited an ID50 of 0.21 and 0.23 μM, respectively. 7‐Phenylpyrazolo[1,5‐a]‐s‐triazin‐4‐one (40) is shown to exhibit an ID50 of 0.047 μM. The structure‐activity relationships of these new phenyl substituted hypoxanthine analogs are discussed and compared with the xanthine analogs 3‐m‐tolyl‐ and 3‐phenyl‐7‐hydroxypyrazolo[1,5‐a]pyrimidin‐5‐ones (90) and (91), previously reported from our laboratory to have ID50 of 0.025 and 0.038 μM, respectively. The presence of the phenyl and substitutedphenyl groups contribute directly to the substrate binding of these potent inhibitors. This work presents an updated study of structure‐activity relationships and binding to xanthine oxidase. In view of the recent elucidation of the pterin cofactor and the proposed binding of this factor to the molybdenum ion in xanthine oxidase, a detailed mechanism of xanthine oxidase oxidation of hypoxanthine and xanthine is proposed. Three types of substrate binding are viewed for xanthine oxidase. The binding of xanthine to xanthine oxidase is termed Type I binding. The binding of hypoxanthine is termed Type II binding and the specific binding of alloxanthine is assigned as Type III binding. These three types of substrate binding are analyzed relative to the most potent compounds known to inhibit xanthine oxidase and these inhibitors have been classified as to the type of inhibitor binding most likely to be associated with specific enzyme inhibition. The structural requirements for each type of binding can be clearly seen to correlate with the inhibitory activity observed. The chemical syntheses of the new 3‐phenyl‐ and 3‐substituted phenylpyrazolo[1,5‐a]pyrimidines with various substituents are reported. The syntheses of various 8‐phenyl‐2‐substituted pyrazolo‐[1,5‐a]‐s‐triazines, certain s‐triazolo[1,5‐a]‐s‐triazines and s‐triazolo[1,5‐a]pyrimidine derivatives prepared in connection with the present study are also described.
Addition de dérivés maloniques sur des β‐énaminones cycliques
Authors: Bellassoued‐Fargeau Marie‐Claude , Graffe Bernadette , Sacquet Marie‐Claude , Maitte P. 
Published: April 2009

AbstractL'addition d'acétonitriles activés 6 sur des β‐énaminocétones 5 dérivées de cétones cycliques et benzyliques, en milieu basique (éthylate de sodium ou triton B) est étudiée. Cette réaction conduit à la formation d'α‐py‐rone 8 à l'exclusion du cycle pyridinique. La structure des nouveaux dérivés 8 est établie par rmn et ir.
Synthesis and spectral characterization of some new N‐substituted 2‐aminobenzothiazoles, 2‐aminothiazolopyridines and 2‐aminothiazoloquinolines
Authors: Sarkis George Y. , Faisal Essam D. 
Published: April 2009

AbstractA series of N‐substituted 2‐aminobenzothiazoles, 2‐aminothiazolopyridines, and 2‐aminothiazoloquinolines were prepared by the cyclization of N,N'‐disubstituted thiourea derivatives by bromine in acetic acid. The uv, ir and nmr data for these compounds are presented and discussed.
Synthèse de nouveaux réactifs génotoxiques, les dérivés nitrés d'anthrafurannes
Authors: Bilger Christine , Demerseman Pierre , Royer René 
Published: April 2009

AbstractOn décrit diverses voies d'accès au formyl‐1 hydroxy‐2 anthracène, au formyl‐2 hydroxy‐1 anthracène et au formyl‐1 hydroxy‐2 méthoxy‐6 anthracène. Ces composés sont employés pour la synthèse des dérivés nitrés sur l'hétérocycle d'anthrafurannes, dans le but de comparer leurs propriétés mutagènes à celles des dérivés nitrés correspondants de naphtofurannes.
The deoxydative substitution reactions of nicotinamide and nicotinic acid N‐oxides by 1‐adamantanethiol in acetic anhydride
Authors: Prachayasittikul Supaluk , Bauer Ludwig 
Published: April 2009

AbstractThe reaction of nicotinamide N‐oxide with 1‐adamantanethiol in acetic anhydride yielded a mixture of 2‐and 6‐(1‐adamantylthio)nicotinamides (49%, in the ratio of 24:1) and 2‐, 5‐, and 6‐(1‐adamantylthio)nicotino‐nitriles (18%, in the ratio of 79:1:20). From a reaction of nicotinic acid N‐oxide with 1‐adamantanethiol, there was isolated 2‐(1‐adamantylthio)nicotinic acid as the only sulfide in 23% yield. Carbonsulfur bond cleavage took place when 2‐(1‐adamantylthio)nicotinic acid, or the corresponding amide or nitrile, were boiled with concentrated hydrochloric acid to furnish 2‐mercaptonicotinic acid and 1‐chloroadamantane, quantitatively. The reaction of nicotinamide N‐oxide alone in acetic anhydride at 135° formed N‐acetyl‐2‐hydroxynicotinamide (61%), 2‐hydroxynicotinonitrile (0.5%) and N,N‐diacetyl‐2‐acetoxynicotinamide (0.8%).
Synthesis and structure of 6‐ and 7‐(acylmethyl)pteridines
Authors: Abdel‐Hady Sayed A. L. , Badawy Mohamed A. , Mosselhi Mosselhi A. N. , Ibrahim Yehia A. 
Published: April 2009

Abstract6‐(Acylmethyl)‐7‐hydroxypteridines 7‐14 as well as the isomeric 7‐(acylmethyl)‐6‐hydroxypteridines 15‐22 were prepared by condensation of 5,6‐diaminouracils 1 and 2 with ethyl aroylpyruvates 3‐6 in pyridine and hydrochloric acid, respectively. The structures of the newly synthesized compounds were confirmed by their hydrolysis into the 7‐hydroxy‐6‐methyl‐23, 24 and 6‐hydroxy‐7‐methylpteridines 25 and 26. The synthesis of the 2‐(methylthio) derivative 28 is also described.
Synthesis of water soluble 8‐substituted 5‐deazaflavins
Authors: Link P. A J. , Van Der Plas H. C. , Müller F. 
Published: April 2009

AbstractBy oxidative cyclization of 5,5′‐arylmethylenebis(6‐methylaminouracil) derivatives with diethyl azodicarb‐oxylate a number of 5‐deazaisoalloxazines were synthesized having at the C(8) position a substituent that causes a bathochromic shift varying between 20 and 130 nm, depending on the substituent. To increase the solubility in aqueous media 8‐substituted 5‐deazaflavins were prepared having a carboxymethyl group at the N(3) position. The carboxymethyl group was introduced prior to the oxidative cyclization.
Presence of an N‐6 acetate group shifts the alkylation site of the ambident nucleophile sodium 1‐N‐methylisoguanide
Authors: Nachman Ronald J. 
Published: April 2009

AbstractInclusion of an N‐6 acetate into the ambident nucleophile, sodium 1‐N‐methylisoguanide, resulted in a shift in alkylation preference from N‐9 to N‐3. The preparation of the N‐6 acetate of 1‐N‐methylisoguanine, 9‐N‐acetyl‐1‐N‐methylisoguanine (4), and related acetate analogs are described and evidence presented for their structural determination. Analysis of long range 13C‐1H coupling data facilitated the structural elucidation of the predominant alkylation products and provided evidence for the unusual N‐7 hydrogen tautomeric form in one of them, 3‐N‐benzyl‐6‐N‐acetyl‐1‐N‐methylisoguanine (8).