bluuebunny/crossref_metadata_2025_split huggingface dataset:
Henry Gray's Anatomy
Authors: Pearce J.M.S. 
Published: March 2009

AbstractLittle is generally known of Henry Gray, the author of Gray's Anatomy, and even less of his colleague Henry Vandyke Carter, who played a vital role in the dissections and illustrations leading to the production of the first volume in 1859. This essay attempts to sketch briefly the salient, know aspects of these two men and their divergent careers. It traces succinctly the subsequent fate of the unique anatomy book that has influenced and instructed almost every student of medicine. Clin. Anat. 22:291–295, 2009. © 2009 Wiley‐Liss, Inc.
Attitudes to anatomy dissection in an Irish medical school
Authors: Cahill Kevin C. , Ettarh Raj R. 
Published: March 2009

AbstractMany studies around the world have looked at the stresses placed on medical students by cadaveric dissection. Although these studies have linked the use of cadavers in medical teaching to stress, some investigations have suggested an association with severe psychological stress and even post‐traumatic stress disorder. This study assessed the attitudes of medical and biomedical sciences students in an Irish medical school towards cadaveric dissection by recording, through a questionnaire, their perceptions and experience before initial exposure to dissection and subsequently examining their attitudes after the first dissection and after 9 weeks. Student attitudes towards the dissecting room remained consistently positive for the duration of the study with only a minority of respondents reporting negative symptoms. Pre‐existing attitudes to the idea of dissection were unaffected by exposure and subsequent continuous experience of dissection. The majority of students in this study did not find the dissecting room experience stressful, and considered time spent in the dissecting room valuable. However, the proportion of students with negative experiences in the dissecting room was higher than has been reported in previous studies. Many respondents felt they could be better prepared for the dissecting room experience, indicating an increasing requirement for effective preparatory programmes. Clin. Anat. 22:386–391, 2009. © 2009 Wiley‐Liss, Inc.
Cover Picture: Exploring the Implications of Vitamin B12 Conjugation to Insulin on Insulin Receptor Binding (ChemMedChem 3/2009)
Authors: Petrus Amanda K. , Allis Damian G. , Smith Robert P. , Fairchild Timothy J. , Doyle Robert P. 
Published: March 2009

AbstractThe cover picture shows three views of a vitamin B12–insulin conjugate bound to transcobalamin II, docked in the insulin receptor (IR). This study reveals how the structure of an orally deliverable insulin changes in solution after vitamin B12 conjugation and its effect on IR binding capacity. The results demonstrate that chemical modification of insulin by linking relatively large pendant groups does not interfere with IR recognition. For more details, see the Full Paper by T. J. Fairchild, R. P. Doyle, et al. on p. 421 ff.magnified image
The dependence on gp130 cytokines of axotomy induced neuropeptide expression in adult sympathetic neurons
Authors: Habecker Beth A. , Sachs Hilary Hyatt , Rohrer Hermann , Zigmond Richard E. 
Published: March 2009

AbstractAdult peripheral neurons exhibit dramatic changes in gene expression after axonal injury, including changes in neuropeptide phenotype. For example, sympathetic neurons in the superior cervical ganglion (SCG) begin to express vasoactive intestinal peptide (VIP), galanin, pituitary adenylate cyclase activating polypeptide (PACAP), and cholecystokinin after axotomy. Before these changes, nonneuronal cells in the SCG begin to express leukemia inhibitory factor (LIF). When the effects of axotomy were compared in LIF−/− and wild‐type mice, the increases in VIP and galanin expression were less in the former, though significant increases still occurred. LIF belongs to a family of cytokines with overlapping physiological effects and multimeric receptors containing the subunit gp130. Real‐time PCR revealed large increases in the SCG after axotomy in mRNA for three members of this cytokine family, interleukin (IL)‐6, IL‐11, and LIF, with modest increases in oncostatin M, no changes in ciliary neurotrophic factor, and decreases in cardiotrophin‐1. To explore the role of these cytokines, animals with selective elimination of the gp130 receptor in noradrenergic neurons were studied. No significant changes in mRNA levels for VIP, galanin, and PACAP were seen in axotomized ganglia from these mutant mice, while the increase in cholecystokinin was as large as that seen in wild‐type mice. The data indicate that the inductions of VIP, galanin, and PACAP after axotomy are completely dependent on gp130 cytokines and that a second cytokine, in addition to LIF, is involved. The increase in cholecystokinin after axotomy, however, does not require the action of these cytokines. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2009
Electrical signals polarize neuronal organelles, direct neuron migration, and orient cell division
Authors: Yao Li , McCaig Colin D. , Zhao Min 
Published: March 2009

AbstractDuring early brain development, the axis of division of neuronal precursor cells is regulated tightly and can determine whether neurons remain in the germinal layers or migrate away. Directed neuronal migration depends on the establishment of cell polarity, and cells are polarized dynamically in response to extracellular signals. Endogenous electric fields (EFs) orient cell division and direct migration of a variety of cell types. Here, we show that cell division of cultured hippocampal cells (neuron‐like cells and glial‐like cells) is oriented strikingly by an applied EF, which also directs neuronal migration. Directed migration involves polarization of the leading neurite, of the microtubule‐associated protein MAP‐2 and of the Golgi apparatus and the centrosome, all of which reposition asymmetrically to face the cathode. Pharmacological inhibition of Rho‐associated coiled‐coil forming protein kinases (ROCK) and phosphoinositide 3‐kinase decreased, leading neurite orientation and Golgi polarization in the neurons in response to an EF and in parallel decreased the directedness of EF‐guided neuronal migration. This work demonstrates that the axis of hippocampal cell division, the establishment of neuronal polarity, the polarization of intracellular structures, and the direction of neuronal migration are all regulated by an extracellular electrical cue. © 2009 Wiley‐Liss, Inc.
Diosgenin targets Akt‐mediated prosurvival signaling in human breast cancer cells
Authors: Srinivasan Sowmyalakshmi , Koduru Srinivas , Kumar Raj , Venguswamy Guhan , Kyprianou Natasha , Damodaran Chendil 
Published: March 2009

AbstractIn recent years, Akt signaling has gained recognition for its functional role in more aggressive, therapy‐resistant malignancies. As it is frequently constitutively active in cancer cells, several drugs are being investigated for their ability to inhibit Akt signaling. The purpose of this study is to determine effect of diosgenin (fenugreek), a dietary compound on Akt signaling and its downstream targets on estrogen receptor positive (ER+) and estrogen receptor negative (ER−) breast cancer (BCa) cells. Diosgenin inhibits pAkt expression and Akt kinase activity without affecting PI3 kinase levels, resulting in the inhibition of its downstream targets, NF‐κB, Bcl‐2, survivin and XIAP. The Raf/MEK/ERK pathway, another functional downstream target of Akt, was inhibited by diosgenin in ER+ but not in ER− BCa cells. Additionally, we found that diosgenin caused G1 cell cycle arrest by downregulating cyclin D1, cdk‐2 and cdk‐4 expression in both ER+ and ER− BCa cells resulting in the inhibition of cell proliferation and induction of apoptosis. Interestingly, no significant toxicity was seen in the normal breast epithelial cells (MCF‐10A) following treatment with diosgenin. Additionally, in vivo tumor studies indicate diosgenin significantly inhibits tumor growth in both MCF‐7 and MDA‐231 xenografts in nude mice. Thus, these results suggest that diosgenin might prove to be a potential chemotherapeutic agent for the treatment of BCa. © 2009 UICC
Reactions of furocoumarins. II. Synthetic aminomethyl psoralens via chloromethylation or benzylic bromination
Authors: Kaufman Kurt D. , Erb Dennis J. , Blok Thomas M. , Carlson Robert W. , Knoechel Donald J. , Mcbride Lincoln , Zeitlow Thomas 
Published: March 2009

AbstractSeveral psoralen derivatives have been synthesized in order to evaluate their efficacy as photochemotherapeutic (PUVA) agents, including a variety of 4′‐substituted‐4,5′,8‐trimethypsoralen compounds (1d‐j). Improved synthesis of the very potent photosensitizers 8‐methylpsoralen (6a) and 4,8‐dimethylpsoralen (6b) are described and 6a has been shown to undergo formylation in the 4′‐position. Free radical bromination of 6a and 6b with NBS affords primarily 8‐bromomethyl derivatives (8a and d), which are readily converted into the 8‐aminomethyl derivatives (8c and f) by the Gabriel method. If the 4′‐position is blocked, electrophilic substitution apparently occurs primarily in the 5′‐position of the psoralen system. At least, chloromethylation of 4′‐methylpsoralen (9) affords mainly 5′‐chloromethyl derivatives (10a and d), which also lead to aminomethylpsoralens (10c and f).
Pyranopyrazoles. II. Synthesis and reactions of 1H,6H‐pyrano[2,3‐c]pyrazol‐6‐ones
Authors: Khan Misbahul Ain , Cosenza Alina Guerra , Ellis Gwynn Pennant 
Published: March 2009

AbstractVarious 1H,6H‐pyrano[2,3‐c]pyrazol‐6‐ones (III‐XXIII) were obtained from β‐keto esters and 1H‐pyrazol‐5‐ones or hydrazines. Nitrations, chlorinations and brominations of these pyranopyrazoles were also carried out giving the corresponding derivatives (XXIV‐LXIV). The pyrone ring is the more reactive one in these reactions and the preferred position of attack is the 5‐position. The substitution products are formed by the addition‐elimination route.
Synthesis of 2‐substituted isothiazolopyridin‐3‐ones
Authors: Baggaley Keith H. , Jennings L. John A. , Tyrrell A. William R. 
Published: March 2009

AbstractThe synthesis of some 2‐substituted derivatives 1–4 of all four isomeric isothiazolopyridin‐3‐ones is described. Several novel 1,2‐dithiolopyridin‐3‐ones and 3‐thiones were prepared as intermediates.
The substitution reaction of pyrazine‐2,3‐dicarbonitrile derivatives with ammonia, amines, water and alcohols
Authors: Hirano Hideki , Lee Rachel , Tada Masaru 
Published: March 2009

Abstract5‐Arylpyrazine‐2,3‐dicarbonitriles 1 and 2 give 2‐alkylamino‐5‐arylpyrazine‐3‐carbonitriles 3 and 5 and 3‐alkylamiono‐5‐arylpyrazine‐2‐carbonitriles 4 and 6 by the substitution reaction with amines but give only 3‐aminopyrazine‐2‐carbonitrile derivative on the reaction with ammonia. The reaction of 5‐arylpyrazine‐2,3‐dicarbonitriles (1 and 2) with alcohols in the presence of a base gives 2‐alkoxypyrazine‐3‐carbonitrile derivatives 9 and 13 and 3‐alkoxypyrazine‐2‐carbonitrile derivatives 10 and 14. The reaction of water gives two pyrazinonecarbonitrile derivatives 11 and 12. In these reactions the aryl groups on the pyrazine ring are 3,4‐dimethoxyphenyl and benzo‐15‐crown‐5.
1,2,4‐triazines. III. A convenient and general synthesis of 4H‐[1,3,4]thiadiazolo[2,3‐c][1,2,4]triazin‐4‐ones
Authors: Mizutani Masato , Sanemitsu Yuzuru 
Published: March 2009

Abstract4H‐[1,3,4]Thiadiazolo[2,3‐c][1,2,4]triazin‐4‐ones were prepared by cyclization of 3‐thio‐4‐amino‐1,2,4‐tri‐azine‐3,5(2H,4H)‐diones with a variety of acids in the presence of concentrated sulfuric acid. The synthesis appears to be general.
Nitrogen bridgehead compounds, Part 311H and 13C NMR study of tetra‐ and octahydro‐11H‐pyrido[2,1‐b]quinazolin‐11‐ones
Authors: Hermecz István , Podányi Benjamin , Mészáros Zoltán , Kökösi József , Szász György , Tóth Gábor 
Published: March 2009

AbstractConformational analysis of some tetra‐and octahydro‐11H‐pyrido[2,1‐b]quinazolin‐11‐ones 1‐3 by 1H and 13C nmr revealed that the 9‐methyl‐6,7,8,9‐tetrahydro derivative exists mainly in the conformation containing the methyl group in a quasi‐axial orientation. Of the 1,2,3,4,5,6,7,8‐octahydro compounds, the 9‐methyl derivative 3e contains the methyl group in a quasi‐axial position, while that in the 7‐methyl and the 8‐methyl derivatives 3c,d is in the equatorial position, and the 6‐methyl derivative 3b is a mixture of the two conformers.
The synthesis of 3,5‐dimethylpyrazol‐1‐yl‐vl‐v‐triazolo[4,5‐d]pyridazines and substituted 3,5‐dimethylpyrazol‐1 ‐ylimidazo[4,5‐d]pyridazines
Authors: Draper Randall E. , Castle Raymond N. 
Published: March 2009

AbstractThe synthesis of 4‐(3,5‐dimethylpyrazol‐1‐yl)‐v‐triazolo[4,5‐d]pyridazine, 4‐(3,5‐dimethylpyrazol‐1‐yl)imid‐azo[4,5‐d]pyridazine and several S‐substituted derivatives of 4‐(3,5‐dimethylpyrazol‐1‐yl)imidazo[4,5‐d]pyrid‐azine‐2‐thiol is reported. These syntheses were carried out to provide a variety of interesting compounds for biological screening.
Synthesis of crown‐ether precocenes
Authors: Camps F. , Coll J. , Ricart S. 
Published: March 2009

AbstractPreparation of potential insect antijuvenile hormone agents with 15‐crown‐5 and 18‐crown‐6 moieties connecting the C‐6 and C‐7 positions of the 2 H‐chromene ring of precocenes is described.
1H‐pyrazolo[3,4‐d]thieno[2,3‐b]pyridine and its derivatives
Authors: Khan Misbahul Ain , Rolim Alice Maria Coimbra , Guarçoni Antonio Elydio 
Published: March 2009

AbstractThe synthesis of the parent ring system and some of the derivatives of 1H‐pyrazolo[3,4‐d]thieno[2,3‐b]pyridine are described.
Oxidation of bis‐aroylhydrazones of 3,3‐dimethylpentane‐2,4‐dione and thermal decomposition of the oxidation products
Authors: Stephanidou‐Stephanatou J. 
Published: March 2009

AbstractOxidation of the title bis‐aroylhydrazones 2 with lead tetraacetate gives l‐aroyl‐5‐aroylazo‐3, 4, 4, 5‐tetramethyl‐2‐pyrazolines 6 in good yields. The aroylazopyrazolines 6 decompose by refluxing in chloroform or ethanol solution to l‐aroyl‐5‐hydroxy‐3, 4, 4, 5‐tetramethyl‐2‐pyrazolines 3, l‐aroyl‐5‐methylene‐3, 4, 4‐trimethyl‐2‐pyrazoles 10 and 1‐aroyl‐3, 4, 4, 5‐tetramethyl‐2‐pyrazolines 11. The spectral data of the prepared compounds, as well as the reaction mechanisms are discussed.
Potential cerebral perfusion agents. Synthesis and evaluation of new radioiodinated barbituric acid analogs
Authors: Srivastava Prem C. , Guyer Clarence E. , Knapp Furn F. 
Published: March 2009

AbstractTwo new 125I‐labeled barbituric acid analogs, 5‐ethyl‐5‐(E‐1‐iodo‐1‐penten‐5‐yl)2‐thiobarbituric acid (4) and 5‐ethyl‐5‐(m‐iodophenyl)barbituric acid (7), have been prepared and evaluated in rats as potential cerebral perfusion agents. Annulation of 2‐ethyl‐2‐(E‐1‐iodo‐1‐penten‐5‐yl)malonate (3) with thiourea in the presence of sodium ethoxide gave the 5‐ethyl‐5‐(E‐1‐iodo‐1‐penten‐5‐y1)‐thiobarbituric acid (4). Diethyl 2‐ethyl‐2‐phenyl‐malonate was treated with thallium(III) trifluoroacetate followed by addition of aqueous potassium iodide to provide diethyl 2‐ethyl‐2‐(m‐iodophenyl)malonate (10). The malonic ester derivative 10 was condensed with urea in the presence of sodium hydride to give the desired 5‐ethyl‐5‐(m‐iodophenyl)barbituric acid (7), and a decarbethoxylation product, 2‐(m‐iodophenyl)butyric acid (11). Iodine‐125‐labeled 4 and 7 were synthesized in the same manner and the tissue distribution of these new agents evaluated in rats. Both [125I] 4 and [125I] 7 showed high brain uptake. Significant in vivo deiodination was detected with [125I] 4 whereas [125I] 7 was found to be stable to deiodination.
Strained heterocyclic systems. 11. Crystal and molecular structure of 1,2‐dihydrocyclobuta[b]quinoline
Authors: Deroski Betty R. , Markgraf J. Hodge , Ricci John S. 
Published: March 2009

AbstractThe structure of the title compound (1) has been elucidated by an X‐ray crystal determination. The crystals are triclinic, space group PI with a unit cell of dimensions a = 6.6109(5), b = 7.5939(4), c = 9.3171(6), α = 77.133(5), β = 75.566(6), γ = 63.575(5). The model was refined to an R value (unweighted) of 4.3% for 1551 independent reflections. The distortion of the heterocyclic ring, with a CNC bond angle of 112.5,° is in accordance with a prior calculation and relates to the observed reduction in basicity.
Regioselective arylation of 3‐bromopyridine
Authors: Comins Daniel L. , Mantlo Nathan B. 
Published: March 2009

AbstractThe addition of aryl Grignard reagents to the 1‐phenoxycarbonyl salt of 3‐bromopyridine affords 2‐aryl‐5‐bromo‐1‐phenoxycarbonyl‐1,2‐dihydropyridines and 4‐aryl‐3‐bromo‐1‐phenoxycarbonyl‐1,4‐dihydropyridines. The crude dihydropyridines were aromatized with o‐chloranil in refluxing toluene to give 4‐ and 6‐aryl‐3‐bromopyridines. The regioselectivity of this two‐step process, 6‐ vs. 4‐substitution, was examined and found to be dependent upon the structure of the Grignard reagent. Unhindered aryl Grignard reagents, e.g., phenyl and 2‐naphthyl, gave mainly 6‐aryl‐3‐bromopyridines (49‐52%) along with 9% of the 4‐substituted isomer and less than 4% of the 2‐aryl‐3‐bromopyridine. Hindered aryl Grignard reagents, e.g., o‐tolyl and 1‐naphthyl, are less regioselective. When a catalytic amount of cuprous iodide is present during the Grignard reaction, nearly exclusive 1,4‐addition results. The crude 4‐aryl‐3‐bromo‐1,4‐dihydropyridines were aromatized with p‐chloranil to provide 4‐aryl‐3‐bromopyridines in good yield and high isomeric purity. The sequential use of the cuprous iodide‐catalyzed Grignard reaction and the “normal” Grignard reaction provided a regiospeci‐fic synthesis of 3‐bromo‐6‐(p‐methoxyphenyl)‐4‐phenylpyridine from 3‐bromopyridine.
Functionalization of substituted 2(1H)‐ and 4(1H)‐pyridones. III. The preparation of substituted 6‐Vinyl‐1,2‐dihydro‐2‐oxo‐ and 1,4‐dihydro‐4‐oxo‐3‐pyridinecarboxylic acids through the chemistry of pyridone dianions
Authors: Dejohn Dana , Domagala John M. , Kaltenbronn James S. , Krolls Uldis 
Published: March 2009

AbstractThe synthesis of various substituted 6‐vinyl‐1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxylic acids from the dianions of 1,2‐dihydro‐6‐methyl‐2‐oxo‐3‐pyridinecarbonitrile and the corresponding 3‐t‐butyl ester is reported. The dianions were generated with LDA in THF at low temperature and reacted with various carbonyl substrates. Several conditions for the dehydration and hydrolysis of these adducts to the vinyl pyridone acids are discussed. Employing the conditions used for the 2‐pyridone analogs, a series of substituted 6‐vinyl‐1,4‐di‐hydro‐4‐oxo‐3‐pyridinecarboxylic acids was prepared through the new dianion of 1,4‐dihydro‐6‐methyl‐4‐oxo‐3‐pyridinecarboxylic acid, t‐butyl ester.
1,4‐benzothiazine derivatives from 2‐aminobenzenethiol and hydrazonoyl halides
Authors: Almirante Nicoletta , Forti Luciana 
Published: March 2009

Abstract2‐Aminobenzenethiol was condensed with alkyl α‐chlorophenylhydrazonoglyoxylates yielding alkyl 2‐(2‐aminophenylthio)‐2‐arylhydrazonoglyoxylates which were cyclized to the corresponding 2‐arylhydrazono‐2,3‐dihydro‐4H‐1,4‐benzothiazin‐3‐ones. Starting from α‐chloro‐α‐arylhydrazonoacetones the corresponding 2‐arylhydrazono‐3‐methylbenzo‐1,4‐benzothiazines were formed.
Mass Spectral Fragmentation Patterns of 11‐(o‐ and p‐R‐Anilino)‐5H‐dibenzo[b,e][1,4]diazepines. IV
Authors: Cortés E. , Martínez R. , Zarza A. 
Published: March 2009

AbstractThe mass spectral fragmentation patterns of eleven 11‐(o‐ and p‐R‐anilino)‐5H‐dibenzo[b,e][1,4]diazepines obtained by electron impact have been studied. All the spectra analyzed contain molecular ions, which are base peak for para isomers and the principal fragmentation routes takes place either from the molecular ion, or from (M+ ‐ 1) ion. There are, however, some deviations from the general fragmentation pattern in the case of 1,4‐dibenzodiazepines with o‐amino and p‐methoxy substituents caused by direct interaction of these groups with the dibenzodiazepine ring.
Pyrrolothiénopyrazines: Etude chimique de la pyrrolo[1,2‐a]thiéno[2,3‐e]pyrazine
Authors: Effi Yamien , Lancelot Jean‐Charles , Rault Sylvain , Robba Max 
Published: March 2009

AbstractLa réactivité de la pyrrolo[1,2‐a]thiéno[2,3‐e]pyrazine 1 est étudiée vis à vis des réactions de quaternarisation, bromation, nitration, Friedel‐Crafts, Vilsmeier‐Haack et de Reissert. La structure des produits obtenus est déduite de l'analyse de leur spectre de rmn ou de masse ou par synthèse univoque.
A synthesis of 2‐β‐D‐ribofuranosyl‐4‐selenazolecarboxamide (selenazofurin) and certain N‐substituted amide derivatives suitable for large scale syntheses
Authors: Dan Cook P. , Mcnamara Dennis J. 
Published: March 2009

AbstractA new process suitable for large scale synthesis of the antitumor‐antiviral agent, 2‐β‐D‐ribofuranosyl‐4‐selenazolecarboxamide (selenazofurin, 1), has been developed. Thus, 1‐O‐acetyl‐2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranose (3) was converted with cyanotrimethylsilane and stannic chloride to the crystalline 2,5‐anhydro‐3,4,6‐tri‐O‐benzoyl‐β‐D‐allononitrile (4) without chromatography. Cyanosugar 4 in ethanol was treated with hydrogen selenide gas to afford stereospecifically the unstable 2,5‐anhydro‐3,4,6‐tri‐O‐benzoyl‐β‐D‐allonoselenoamide (5) which was converted in situ by ethyl bromopyruvate to the stable ethyl 2‐(2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranosyl)‐4‐selenazolecarboxylate (6). Selenazole ethyl ester 6 was deprotected with sodium methoxide affording methyl 2‐β‐D‐ribofuranosyl‐4‐selenazolecarboxylate (7) which was aminated with ammonia to provide selenazofurin (1) or with other amines to provide N‐substituted selenazofurin amides.
Synthesis of [1]benzothieno[2,3‐e]pyrrolo[1,2a]pyrazines and related compounds
Authors: El‐Kashef Hussein , Rault Sylvain , Lancelot Jean‐Charles , Robba Max 
Published: March 2009

AbstractThe synthesis of several [1]benzothieno[2,3‐e]pyrrolo[1,2‐a]pyrazines and other related heterocycles has been described. A study of the nmr spectra of these compounds was also reported.
Synthesis of 7‐substituted imidazo[1,2‐a]pyrimidin‐5(1H)‐ones
Authors: Nugent Richard A. , Murphy Megan 
Published: March 2009

AbstractThe synthesis of 7‐substituted imidazo[1,2‐a]pyrimidin‐5(1H)‐ones by either of 2 methods is reported.
Purine acyclic nucleosides. Unambiguous synthesis of acyclovir via a furazano[3,4‐d]pyrimidine
Authors: Kelley James L. , Schaeffer Howard J. 
Published: March 2009

AbstractAcyclovir was synthesized in five steps from 7‐formamido‐5‐methylthiofurazano[3,4‐d]pyrimidine 2. Alkylation of 2 with 2‐(benzoyloxy)ethoxymethyl chloride, followed by reductive cleavage of the furazan ring gave 9‐[[2‐(benzoyloxy)ethoxy]methyl]‐2‐(methylthio)adenine 5. Hydrolysis of the 6‐amino group of 5, followed by amination of 7 with ammonia gave 9‐[(2‐hydroxyethoxy)methyl]guanine (1, acyclovir).
Facile synthesis of fluorine‐containing [4‐aryl‐4,5‐dihydro‐5‐imino‐1,3,4‐thiadiazol‐2‐ylaryl]methanone, 2‐amino‐4‐aryl‐5‐arylazothiazoles and 3‐aroyl‐4‐acetyl/benzoyl‐5‐methyl‐1‐phenylpyrazoles through N‐aryl‐α‐oxo‐α‐arylethanehydrazonoyl bromide
Authors: Joshi Krishna C. , Pathak Vijai N. , Sharma Sharda 
Published: March 2009

AbstractN‐Aryl‐α‐oxo‐α‐arylethanehydrazonoyl bromides 2 react with potassium thiocyanate in ethanol leading to the formation of [4‐aryl‐4,5‐dihydro‐5‐imino‐1,3,4‐thiadiazol‐2‐ylaryl]methanone 5 in quantitative yield. Treatment of 2 with thiourea and β‐diketones affords 2‐amino‐4‐aryl‐5‐arylazothiazoles 4 and 3‐aroyl‐4‐acetyl/benzoyl‐5‐methyl‐1‐phenylpyrazoles 6 in 65–70 and 60–70% yields respectively. Compound 5 has also been subjected to acetylation and chloroacetylation. All the compounds are characterized by their analytical and spectral (ir, 1H‐nmr and ms) data. Mass fragmentation patterns of these compounds are discussed.