bluuebunny/crossref_metadata_2025 huggingface dataset:
The roles of monocytic heat shock protein 60 and Toll‐like receptors in the regional inflammation response to wear debris particles
Authors: Hao Hsiao‐Nan , Zheng Bingrong , Nasser Sam , Ren Weiping , Latteier Michael , Wooley Paul , Morawa Lawrence
Published: April 2009

The biological response to orthopaedic wear debris is central to peri‐prosthetic tissue inflammation and osteolysis, through mechanisms that include local inflammatory cytokine production. In particular, interleukin‐1 β (IL‐1β) and tumor necrosis factor‐α (TNF‐α|) are generated in high quantities following monocyte accumulation in periprosthetic inflammatory tissue, and these cytokine combine with other inflammatory mediators to trigger osteolysis. Since the precise mechanisms involved in debris‐associated inflammation remain unclear, it is important to understand how wear debris particles initially interact with inflammatory cells. We have previously demonstrated that the severity of the inflammation response is influenced by the size, shape, and quantity of particles accumulated in tissues. The current in vitro and in vivo results indicate that heat‐shock protein (Hsp) expression is elevated when monocytes are exposed to wear debris particles. We have also addressed the mechanisms by which heat‐shock protein 60 (Hsp60) positively modulates inflammatory cytokines via Toll‐like receptor‐4 (TLR4) signal transduction pathway on mononuclear cells. Furthermore, down‐regulation of TLR4 expression using antisense oligonucleotides targeted to TLR4 mRNA suppressed cytokine production in both exogenous Hsp60 and particles stimulated cultures. Collectively, these data indicate that monocytic Hsp60 is an additional inducible immunoregulatory mediator in response to particle‐induced cell stress. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Surface hydration of polymeric (bio)materials: A molecular dynamics simulation study
Authors: Raffaini Giuseppina , Ganazzoli Fabio
Published: April 2009

The surface hydration of some crystalline polymeric (bio)materials is investigated at room temperature using molecular mechanics and molecular dynamics techniques through the statistical distribution of the water molecules as a function of their distance from the surface atoms. Considering different crystalline polymers such as polyethylene, poly(vinylidene fluoride), and poly(m‐phenylene isophthalamide), and in particular their different crystal faces, we can take into account unlike surface chemistries and their subnanoscale topologies. Such features are ultimately related to the intermolecular forces between the exposed groups of the specific crystal face and the water molecules, and those among the polymer chains, which also affects the thermal motion of the surface repeat units. We find that the parallel grooves and depressions that can be formed at the surface by the ordered hydrophobic chains may trap the nearest water molecules at short times, unless the (sub) nanoscale pattern is effectively blurred by the thermal motion of the surface units. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Starch‐based polymeric carriers for oral‐insulin delivery
Authors: Mahkam Mehrdad
Published: April 2009

The objective of this study is to utilize the pH sensitivity of modified carboxymethyl starch (CMS) for oral delivery of insulin. The chemical modification of natural polymers by grafting has received considerable attention in recent years because of the wide variety of monomers available. Methacrylic‐type polymeric prodrugs were synthesized by free radical copolymerization of methacrylic acid, poly(ethyleneglycol monomethyl ether methacrylate) (PEGMA), and carboxymethyl starch (CMS) in the presence of bis‐acrylamide as a cross‐linking agent (CA) and persulfate as an initiator. The pH sensitive nature and ability to control gel permeability indicate that these materials have significant potential for drug delivery applications. Equilibrium swelling studies were carried out in enzyme‐free simulated gastric and intestinal fluids (SGF and SIF, respectively). Insulin was entrapped in these gels, and the in vitro release profiles were established separately in both (SGF, pH 1) and (SIF, pH 7.4). Drug release studies showed that the increasing content of MAA in the copolymer enhances hydrolysis in SIF. In these cases, the biological activity of insulin was retained. These results were used to design and improve protein release behavior from these carriers. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
In vitro kinetic study of growth and mineralization of osteoblast‐like cells (Saos‐2) on titanium surface coated with a RGD functionalized bisphosphonate
Authors: Beuvelot Johanne , Portet David , Lecollinet Grégory , Moreau Marie‐Françoise , Baslé Michel Félix , Chappard Daniel , Libouban Hélène
Published: April 2009

Osteoconduction and osseointegration are the critical stages for implantation success. Peptides containing RGD (Arg‐Gly‐Asp) adhesive sequence are known to promote cell adhesion and consequently to favor osseointegration of medical devices. In this study, RGD peptides were coupled to a bisphosphonate used as an anchor system and chemically adsorbed on polished titanium discs. Two different concentrations, 10−10 mol/L (RGD 10−10) and 10−4 mol/L (RGD 10−4) were compared to non coated discs (RGD 0). Adhesion, spreading, and mineralization of osteoblast‐like cells (Saos‐2) were assessed. Mineralization kinetic was done at 3, 6, 10, 14, and 18 days of culture; the extent of mineral deposits was quantified by image analysis. Histogram repartitions of nuclear area, characterizing cell spreading, showed a shift to higher values in cells cultured on RGD coated titanium disks. Mineralization started at day 3 in the three groups, but had a faster development in the RGD 10−10 group from day 6 to day 18 compared to RGD 0 and RGD 10−4. At day 18, the percentage of mineralized area was significantly higher for RGD 10−10 compared to RGD 0 (p < 0.05). In the present study, this new method was found suitable to anchor RGD containing species on titanium: this favored adhesion and spreading of osteoblast‐like cells and mineralization compared to noncoated titanium. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009
First principles investigation on the ultra‐incompressible and hard TaN
Authors: Zhao Erjun , Hong Bo , Meng Jian , Wu Zhijian
Published: April 2009

The structural, electronic, and mechanical properties of TaN were investigated by use of the density functional theory (DFT). Eight structures were considered, i.e., hexagonal WC, TaN, NiAs, wurtzite, and CoSn structures, cubic NaCl, zinc‐blende and CsCl structures. The results indicate that TaN in TaN‐type structure is the most stable at ambient conditions among the considered structures. Above 5 GPa, TaN in WC‐type structure becomes energetically the most stable phase. They are also stable both thermodynamically and mechanically. TaN in WC‐type has the largest shear modulus 243 GPa and large bulk modulus 337 GPa among the considered structures. The volume compressibility is slightly larger than diamond, but smaller than c‐BN at pressures from 0 to 100 GPa. The compressibility along the c axis is smaller than the linear compressibility of both diamond and c‐BN. The estimated hardness is 34 GPa. Thus, TaN in WC‐type structure is a potential candidate to be ultra‐incompressible and hard. The unique mechanical properties of TaN in WC‐type structure would make it suitable for applications under extreme conditions. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009
Transcranial Doppler detection of venous‐to‐arterial circulation shunts: Criteria for patent foramen ovale
Authors: Sastry S. , MacNab A. , Daly K. , Ray S. , McCollum C.
Published: April 2009

Purpose

As paradoxical embolism is associated with stroke in young adults, migraine, and decompression sickness, the detection of venous‐to‐arterial circulation shunt (v‐aCS), such as patent foramen ovale (PFO), is increasingly important. We compared a rigorous transcranial Doppler (TCD) protocol with transesophageal echocardiography (TEE) to develop criteria for PFO.

Methods

Standardized TCD was performed 2 weeks before simultaneous TEE and TCD in 39 patients aged 15–39 following ischemic stroke (n = 33) or myocardial infarction (n = 6). V‐aCS was investigated by contrast sonography. During standardized TCD, contrast injections were performed twice, at rest and with cough and Valsalva maneuvers. TCD and TEE were recorded and analyzed independently by ‘blinded’ observers.

Results

All 16 of the 39 patients with PFO on TEE had more than 15 micro‐emboli on standardized TCD; in 14 of these 16, paradoxical embolization required no provocation. Three of 9 patients with ‘major’ v‐aCS (>50 microbubble emboli at rest or >10 at rest with >80 on provocation) on standardized TCD were not identified by TEE as having large shunts.

Conclusion

The standardized TCD protocol is sensitive in the diagnosis of PFO and with the use of provocation maneuvers measures the functional importance of v‐aCS more accurately than TEE. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Sonographic measurements of subcutaneous fat in obese individuals may correlate better with peripheral artery disease indices
Authors: Tsitsilonis Serafim , Vlachos Ioannis S. , Bampali Andromachi , Revenas Konstantinos , Votteas Vassilios , Perrea Despina N.
Published: April 2009

Purpose.

The purpose of this study was to investigate the association of various methods for body fat assessment with indices of peripheral artery disease in the deep and superficial femoral arteries.

Methods.

The intima–media thickness (IMT), maximal IMT (max IMT), femoral wall thickness (FWT), maximal FWT (max FWT), cross‐sectional intima media area (CIMA), and atherosclerotic burden score (ABS) were measured sonographically in 26 subjects. The minimum thickness of the abdominal subcutaneous fat layer (Smin) was measured sonographically close to the xyphoid process, and body fat percentage was calculated using various formulas.

Results.

Smin correlated significantly with body fat percentage calculated with all formulas and was the sole parameter that was associated significantly with all the femoral artery atherosclerotic indices IMT: r = 0.74, p < 0.001; max IMT: r = 0.53, p < 0.05; FWT: r = 0.78, p < 0.001; max FWT: r = 0.57, p < 0.005; ABS: r = 0.52, p < 0.05; CIMA: r = 0.86, p < 0.001; Smin was the major independent predictor of femoral IMT on a multiple stepwise regression analysis (β = 0.02; SE = 0.008, R2 = 0.35, p < 0.05).

Conclusions.

Smin correlates better than indirect indices and formulas of body fat estimation with markers of extracoronary atherosclerosis. Sonographic measurement of Smin may serve in the future as a useful tool in everyday clinical practice. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Sonographic diagnosis of ectopic pregnancy 2 years after total hysterectomy
Authors: Barhate Kishor P. , Domkundwar Shilpa , Patil Nirupama , Pai Bhujang
Published: April 2009

We report a case of a 35‐year‐old multigravida with a chief complaint of 8 days of mild pain in the lower abdomen with history of vaginal hysterectomy 2 years prior. Ultrasonography and MRI showed a gestational sac‐like structure with a fetal pole in the pelvis. Urine pregnancy test was positive with increased beta‐HCG levels. Diagnosis of ectopic pregnancy was made. Surgical exploration and subsequent histopathology confirmed the sonographic findings. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Ultrastructural changes of platelet aggregates and fibrin networks in a patient with renal clear cell adenocarcinoma: A scanning electron microscopy study
Authors: Pretorius Etheresia , Bornman Maria S. , Reif Simon , Oberholzer Hester M. , Franz Robert C.
Published: April 2009

A 47‐year‐old male patient presented with weight loss, hematuria, and a left renal mass, which proved to be a clear cell renal carcinoma with multiple liver, pulmonary and bone metastases. The platelet count was raised initially (414 × 109/L) but declined 10 weeks after a debulking procedure followed by chemotherapy. Fibrin clots were prepared for scanning electron microscopy (SEM) by adding human thrombin to platelet rich plasma (derived by differential centrifugation of fresh blood samples taken from the patient as well as controls). The clots were washed, fixed in 2.5% glutaraldehyde and Dulbecos phosphate buffered saline and prepared for SEM with a Zeiss Ultra 55 FEG SEM. The SEM photographs revealed an altered morphology of the platelet aggregates with multiple breakages in the platelet membrane, showing a pock‐marked, crenated, prune‐like appearance as opposed to the smooth rounded globular membrane of the controls. The ultrastructural morphology of the fibrin bound platelet aggregates in this patient with renal carcinoma therefore showed a disrupted cytoskeletal architecture which appears to be similar to the apoptotic changes of programmed cell death as described by Bornman et al. (2007) and Pretorius et al. (2008). These features may well be a distinct ultrastructural hematological manifestation of a previously unidentified paraneoplastic syndrome. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc.
Synthesis of some novel tetracyclic imidazole derivatives
Authors: Lombardino Joseph C.
Published: April 2009

Representatives have been made of three new heterocyclic systems (IIH) containing an imidazole ring. Synthetic routes are described for compounds of type II where X = CH2 (8H‐dibenzo[3,4: 6,7]cyclohept[1,2‐d] imidazoles), and X = CH2CH2 (8,9‐dihydrodibenzo[3,4:7,8]cyclooct[1,2‐d] imidazoles) and X = S (dibenzo[2,3:6,7] thiepin] 4,5‐d] imidazoles). In addition, improved syntheses are presented for some previously known compounds employed as intermediates in this work.
Synthesis of benz[e] indole and benz[g] indole carboxaldehydes
Authors: Hosmane R. S. , Hiremath S. P. , Schneller S. W.
Published: April 2009

The Vilsmeier‐Haack formylation reaction and several additional reactions have been employed to prepare a variety of benz[e]‐ and benz[g] indole‐2‐ and 3‐carboxaldehydes. Similar conditions have been utilized to prepare several 2,3‐disubstituted benz[g] indole‐5‐carboxaldehydes.
Macrocyclic polycther sulfide syntheses. The preparation of thia‐crown‐5, 6 and 7 compounds
Authors: Bradshaw J. S. , Hui J. Y. , Chan Y. , Haymore B. L. , Izatt R. M. , Christensen J. J.
Published: April 2009

Macroeyclic polyether sulfides have been prepared by reacting an oligoethylene glycol dichloride with a dimercaptan or sodium sulfide as reported in a previous paper (6). The following new compounds were prepared: 1,4,7‐trithia(15‐crown‐5) (1); 1,4,10‐trithia(15‐crown‐5) (II): 1,4,7,10‐tetrathia(15‐crown‐5) (III); I‐thia(18‐crown‐6) (IV); 1,4‐dithia(18‐crown‐6) (V); 1,7‐dithia(18‐crown‐6) (VI); 1,4,7‐trithia(18‐crown‐6) (VII); 1,7‐dithia(21‐crown‐7) (VIII); and 1,4,7‐trithia(21‐crown‐7) (IX). The melting points of these and previously reported thia‐crown compounds correlate with their structures. X‐ray analyses of two thia‐crown compounds indicate that the large sulfur atoms are directed away from the center of the ring.
Synthesis of nucleosides of 5‐substituted‐1,2,4‐triazole‐3‐carboxamides
Authors: Naik S. R. , Witkowski J. T. , Robins Roland K.
Published: April 2009

Nucleosides of 5‐substituted‐1,2,4‐triazole‐3‐carboxamides were prepared by the acid‐catalyzed fusion procedure and by glycosylation of the appropriate trimethylsilyl derivative. The following nucleosides were obtained in two steps starting from methyl 4‐substituted‐1,2,4‐triazole‐3‐carboxylates: 5‐chloro‐1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐3‐carboxamide (6), 3‐chloro‐1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐5‐carboxamide (5), 3‐nitro‐1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐5‐carboxamide (12), 3‐amino‐1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐5‐carboxamide (13), 5‐methyl‐1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐3‐carboxamide (15), and 3‐methyl‐1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐5‐carboxamide (16). In addition, 5‐amino‐1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐3‐carboxamide (7), and 1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐3‐carboxamide‐5‐thiol (8) were prepared from 6.
1,3‐Dipolar addition of formonitrile oxide, and hydroxyiminoacetonitrile oxide to some olefins. The synthesis of isoxazolidino[2,3‐b]‐Δ3‐l,2,5‐oxadiazolines
Authors: Fajkos J. , Edwards J. A.
Published: April 2009

The 1,3‐dipolar addition of formonitrile oxide and hydroxyiminoacetonitrile oxide to a variety of olefins is described. The 3‐anti‐aldoximino‐Δ2‐isoxazolines, resulting from the addition of the dimerie hydroxyiminoacetonitrile oxide to the olefinie substrate, undergo base‐catalyzed cyclization to yield novel isoxazolidino[2,3‐b]‐Δ3‐l,2,5‐oxadiazolines. The latter products are rearranged to α‐oximino‐γ‐lactones after additional treatment with base.
Quinazolines and 1,4‐benzodiazepines. LXI. Syntheses of 7‐Acetyl‐1,4‐benzodiazepines
Authors: Ning Robert Y. , Madan Pradeep B. , Sternbach Leo H.
Published: April 2009

Methods for the synthesis of the biologically active 7‐acetyl‐1,3‐dihydro‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐one (6) are described. This includes two new methods for the preparation of 5‐acetyl‐2‐aminobenzophenone (4). The crucial steps in these syntheses involve, respectively, the oxidation of an ethyl group to an acetyl group with permanganate or ceric ions (2 → 3; 5 → 6), the selective reaction of methyl lithium with the cyano group of 7‐cyano‐1,3‐dihydro‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐one (8) and the efficient condensation of benzyl cyanide with the ethylene ketal of p‐nitroacetophenone to form the anthranil 11.
Sur quelques analogues fluores des [1] benzothiopyrano[4,3‐b]indoles et des 6H[1] benzothiopyrano[4,3‐b] quinoleines
Authors: Jacquignon A. Croisy Et P. , Fravolini A.
Published: April 2009

La synthèse d'analogues fluorés en 2,3 ou 4 des [1]benzothiopyrano[4,3‐b]indoles cancérogènes et des 6H[1]benzothiopyrano[4,3‐b]quinoléines a été effectuée a partir des fluoro thiochromannones correspondantes.

Les spectres de RMN à 60 Mc sont décrits pour les six molécules de base.

Les tests biologiques relatifs à la recherche d'un éventuel pouvoir cancérogène sont actuellement en cours et permettent d'ores et déjà de classer une des molécules obtenues dans la famille des sarcomogènes puissants.
Synthesis of substituted thieno[2,3‐b]pyrroles
Authors: Crochet Roy A. , Boatright Joan T. , Blanton C. Dewitt , Wie Chwang T. , Hochholzer W. E.
Published: April 2009

A relatively simple route for synthesis of substituted thieno[2,3‐b]pyrroles from readily available starting material and data for structural assignment are reported.
Degradative ring opening of pyrido and pyrazino 3‐benzenesulfonyloxyuracils and their conversion to condensed pyrazolones and triazolones
Authors: Tserng Kou‐Yi , Bauer Ludwig
Published: April 2009

Ring opening, followed by an immediate Lossen rearrangement, of 3‐benzenesulfonyloxypyrido[3,2‐d, 3,4‐d and 4,3‐d]pyrimidine‐2,4(1H,3H)diones with sodium methoxide in methanol furnished good yields of the methyl esters of 3‐[2‐(methoxycarbonyl)hydrazino]‐2‐, 3‐[2‐(methoxycarbonylhydrazino]‐4‐ and 4‐[2‐(methoxycarbonyl)hydrazino]‐3‐pyridinecarboxylic acids, respectively. These hydrazino esters were cyclized to the corresponding pyridopyrazolones. However, the reaction of 3‐benzenesulfonyloxypyrido[2,3‐d]pyrimidine‐2,4(1H,3H)dione with sodium methoxide produced 8‐methoxycarbonyl‐s‐triazolo[4,5‐a]pyridin‐3(2H)one. In similar fashion, sodium methoxide converted 3‐benzenesulfonyloxylumazine to 8‐methoxycarbonyl‐s‐triazolo[4,3‐a]pyrazin‐3(2H)one.
Synthesis of new heterocycles of the benzo[a] quinolizine group V. Synthesis of the 1‐methylhexahydrobenzo[a] quinolizin‐2‐ones. Preparation of the cis‐junction isomer
Authors: Buzas A. , Cossais F. , Jacquet J. P. , Novák L. , Szántay C. S.
Published: April 2009

The reaction of 3,4‐dihydro‐6,7‐dimethoxyisoquinoline hydrochloride on ethyl vinyl ketone yields two cis and trans benzo[a quinolizinone isomers in variable proportions depending on the pH of the reacting medium. The cis junction isomer can be stabilized and isolated as the β‐propionylethylquinolizinium chloride quaternary salt.
Studies on the syntheses of heterocyclic compounds. Part DLIV. A total synthesis of (±)‐coreximine by thermolysis
Authors: Kametani Tetsuji , Takemura Makoto , Ogasawara Kunio , Fukumoto Keiichiro
Published: April 2009

Thermolysis of the dibenzyloxy‐substituted benzocyclobutene IXc effected cyclization and mono‐O‐debenzylation to provide a facile route to the total synthesis of the protoberberine isoquinoline (±)‐coreximine (XIII).
Heterocyclic synthesis with β‐ketosulfoxides IV. Synthesis of 3‐substituted chromones
Authors: Klutchko S. , Cohen M. P. , Shavel J. , Von Strandtmann M.
Published: April 2009

A novel synthesis of 3‐(hydroxymethyl)chromones from o‐hydroxy‐ω‐(methylsulfinyl)acetophenones has been developed. These have been utilized in the synthesis of 3‐formyl, 3‐cyano, 3‐carboxy, 3‐carboxamido, 3‐chloromethyl, 3‐aminomethyl and 3‐methoxymethylchromones.
A study of the spectra and acidity of 4,5‐dihydro‐1H‐benz[g]indazol‐7‐ol and 2,3a,4,5‐tetrahydro‐7‐hydroxy‐3a‐methyl‐3H‐benz[g]indazol‐3‐one
Authors: Thyvelikakath George X. , Bramlett Linda J. , Snider Theodore E. , Morris Don L. , Haslam Donald F. , White Wesley D. , Purdie Neil , Durham N. N. , Berlin K. Darrell
Published: April 2009

The synthesis of 2,3a,4,5‐tetrahydro‐7‐hydroxy‐3H‐benz[g]indazol‐3‐one is recorded for the first time. Infrared, pmr, and uv spectral analysis of this pyrazolone and of 4,5‐dihydro‐1H‐benz[g]indazol‐7‐ol strongly support the presence of one tautomer in each case. Measurements of pKa values are in agreement with the proposed tautomeric structures based upon comparisons with simpler model systems. The data are taken in aqueous solution since the compounds are soluble at 10−5 M and the results may more closely approximate that for the structure under physiological conditions.
The synthesis and chemical reactions of certain pyrazolo[1,5‐a]‐1,3,5‐triazines
Authors: Kobe Jože , Robins Roland K. , O'Brien Darrell E.
Published: April 2009

3‐Aminopyrazole was utilized as a starting material for the preparation of certain pyrazolo‐[1,5‐a]‐1,3,5‐triazines. 4‐Chloro‐2‐methylthiopyrazolo[1,5‐a]‐1,3,5‐triazine was prepared and used for studies of nucleophilic displacement reactions, and it has been found that both the chloro and methylthio groups may be displaced by nucleophiles. By modifications of these procedures we have prepared the adenine, hypoxanthine, and xanthine analogs of the pyrazolo‐[1,5‐a]‐1,3,5‐triazine ring system. Electrophilic substitution occurs in the 8‐position of this ring system. The methyl group was introduced into the 4‐position by a novel ring opening and ring closing of the 1,3,5‐triazine ring.
Synthesis of 2‐chloro‐2‐imidazoline and its reactivity with aromatic amines, phenols, and thiophenols
Authors: Trani Aldo , Bellasio Elvio
Published: April 2009

2‐Chloro‐2‐imidazoline has been synthesized by the reaction of ethylene‐thiourea with chlorine in aqueous solution at 50°. The compound was reacted with aromatic amines, phenols, and thiophenols.
Thienyl methacrylates
Authors: Hawkins Richard T.
Published: April 2009

Thienyl methacrylates have been synthesized and characterized. Thienyl methacrylate has been homo‐ and copolymerized.
5‐vinyl pyrimidines. I. Synthesis
Authors: Feit B. A. , Teuerstein A.
Published: April 2009

A total synthesis of 5‐vinyl pyrimidine and some of its substituted derivatives is described. The following vinyl pyrimidines have been prepared: 5‐vinyl pyrimidine, 5‐vinyl‐4,6‐dimethoxy pyrimidine, 5‐(α‐bromo) vinyl‐4,6‐dimethoxy pyrimidine.
Chemical constitution and activity of bipyridyliium herbicides. Part VIII. 4‐Bromo‐6,7‐dihydrodipyrido[1,2‐α:2′,1′‐c]‐pyrazinediium dibromide and related compounds
Authors: Pojer P. M. , Summers L. A.
Published: April 2009

6‐Chloro‐2,2′‐bipyridyl reacts with sodium alkoxides to afford the corresponding 6‐alkoxy‐2,2′‐bipyridyls, which form 6,7‐dihydro‐4‐oxodipyrido[1,2‐a:2′,1′‐c]pyrazinium bromide on treatment with 1,2‐dibromoethane. 6‐Chloro‐2,2′‐bipyridyl with this reagent gives 4‐bromo‐6,7‐dihydrodipyrido[1,2‐a:2′,1′‐c]pyrazinediium dibromide.
Stereoselective additions of phenylmagnesium bromide to N‐substituted‐2‐azabicyclo[2.2.2]octa‐5‐ and 6‐ones
Authors: Borne Ronald F. , Clark C. Randall , Wade Norman A.
Published: April 2009

The addition of phenylmagnesium bromide to ketones derived from 2‐azabieyclo[2.2.2]‐octane was shown to proceed in a stereoselective manner to produce only one of two possible phenyl alcohol derivatives. Factors affecting the course of addition and the determination of relative stereochemistry of the resulting phenyl alcohols are discussed.
Novel protecting groups. III. A study of the reaction of 2‐picolyl 1‐oxide derivatives with acetic anhydride
Authors: Ikeda Kazuyoshi , Tsuchida Kiyomi , Monma Taeko , Mizuno Yoshihisa
Published: April 2009

2‐Picolyl 1‐oxides (I‐VIII) were prepared and the reaction of I‐VII with acetic anhydride was followed by the gas chromatography. In this reaction, the increasing order of the rate of disappearance of the 2‐pieolyl 1‐oxide derivatives was found to be IV>III>VII>I>VI>II>V. Under comparable conditions, a half‐life of VIII is midway between that of I and VI. The 2‐picolyl 1‐oxide group was found to be potentially useful for the blocking of hydroxyl functions of phosphates (viz., VIII), although ca. 4% of the organic phosphate remained unblocked after the deblocking procedure (acetic anhydride treatment and subsequent hydrolysis).
1,2,4‐Triazines. VI. Imidazo[1,2‐b]‐as‐triazines
Authors: Lalezari I. , Levy Y.
Published: April 2009

Imidazo[1,2‐b]‐as‐triazines were obtained in high yields by heating substituted glyoxaldoximes with 1,2‐diaminoimidazoles in the presence of hydrochloric acid. Phenylglyoxal hydrate in a similar reaction afforded a mixture of 2‐ and 3‐diphenyl‐6‐arylimidazo[1,2‐b]‐as‐triazines. α‐Ketoacids and 1,2‐diaminoimidazoles in the presence of hydrochloric acid afforded 2,6‐disubstituted‐4H‐imidazo[1,2‐b]‐as‐triazin‐3‐ones.
Novel polycyclic heterocycles. XI. Synthesis of 11,12‐dihydropyrido[2,1‐b] [1,3]benzodiazepines, 6H‐pyrido[1,2‐c] [1,3,5]benzoxadiazepines, and 6H‐Pyrido[1,2‐c] [1,3,5]benzothiadiazepines
Authors: Petigara R. B. , Yale Harry L.
Published: April 2009

An unusually facile dehydrobromination, involving the ortho‐bromine atom and the = NH proton of a 2‐imino‐1‐(phenethyl)‐, 2‐imino‐1‐(phenoxymethyl)‐, or 2‐imino‐1‐(phenylthiomethyl)‐pyridine (2a‐e) has led to the synthesis of three novel bridgehead nitrogen tricyclic systems: 11,12‐dihydropyrido[2,1‐b] [1,3]benzodiazepines (3a,b), 6H‐pyrido[1,2‐c] [1,3,5]benzoxadiazepines (3c,d) and 6H‐pyrido[1,2‐c][1,3,5]benzothiadiazepines (3e). As anticipated, these cyclizations required a base, e.g., potassium carbonate, and a catalyst, e.g., copper bronze. What was unusual, was that these reactions occurred in methanol or n‐propanol, under reflux, either under anhydrous conditions, or in the presence of large amounts of water. The pmr spectra of these compounds are discussed.
Synthése, stéréochimie, et réactivité thermique de (N‐méthylidenealkylamino)‐2 aziridines
Authors: Gelas‐Mialhe Yvonne , Hierle Rolland , Vessière Roger
Published: April 2009

1‐Alkyl‐2‐(N‐methylidenealkylamino)aziridines are obtained by the reaction of primary amines with either α‐chloroacraldehyde or α‐chlorocrotonaldehyde. Structural assignments are made by nmr spectroscopy. The thermal rearrangement of 1‐alkyl‐2‐(N‐methylidenealkylamino)‐3‐methylaziridines to pyrroles is described.
Reaction of alkylhydrazines. II. vic‐disubstituted pyridines and pyridopyridazines
Authors: Nematollahi Jay , Kasina Sudhakar , Maness Dale
Published: April 2009

A series of 2,3‐disubstituted pyridines and pyrido[2,3‐d]pyridazines have been synthesized. The molecular structure of the compounds have been elucidated by using chromatography; ir, nmr, and mass spectrometry; and chemical methods, in particular metal complexation. The new compounds offer interesting chemistry and are envisaged to function as potential chemotherapeutic and pharmacodynamic agents.
Chemistry of thienopyridines. XVIII. Lithiation as a route to 2‐ and 3‐substituted thieno[2,3‐b]pyridines
Authors: Klemm L. H. , Merrill R. E.
Published: April 2009

Treatment of thieno[2,3‐b]pyridine (1a) with n‐butyllithium in hexane‐tetramethylethylene‐diamine at −70° plus subsequent addition of dimethylformamide produced 2‐formyl‐Ia (66%). Halogen‐metal exchange between 3‐bromothieno[2,3‐b]pyridine and n‐butyllithium was effected in ether at −70. Further reaction of the 3‐lithio‐Ia intermediate with a variety of carbonyl compounds gave 3‐substituted thieno[2,3‐b]pyridines bearing formyl (77%), acetyl, benzoyl, chloroacetyl, ethoxycarbonyl, N‐phenylcarbamyl, and diphenyl hydroxymethyl groups. Common characteristics of these derivatives in pmr and mass spectra are noted.
A new synthesis of 2,3‐disubstituted indoles
Authors: Hillard J. , Reddy K. V. , Majumdar K. C. , Thyagarajan B. S.
Published: April 2009

A novel synthesis of 2,3‐disubstituted indoles starting from N‐alkyl‐N‐propvnyl anilines is described. The reactions employed are analogous to the thermal rearrangement of aryl propynyl sulfoxides.
Selenium heterocycles XIV. 2,6‐diaryltetrahydroselenopyran‐4‐ones
Authors: Lalezari I. , Ghanbarpour A. , Ghapgharan F. , Niazi Jafari‐Namin M. , Jafari‐Namin R.
Published: April 2009

In our previous communications, we have reported that selenium heterocycles could be easily obtained either by using selenium dioxide (3) or by selenium (4). In continuation of our studies on the synthesis and chemistry of selenium heterocycles, it was of interest to use aluminum selenide as the precursor of selenium in the preparation of selenium heterocycles.
Strained heterocyclic systems. VIII. The mass spectral fragmentations of some arylquinolines and quinoline N‐oxides
Authors: Koch Charles W. , Milberg Richard M. , Katt Robert J. , Markgraf J. Hodge , Wege P. M.
Published: April 2009

High resolution mass spectra of compounds 1—8 were investigated. For the quinolines (1–3) the absence of major peaks other than M+ and (M‐1)+ reflects the stability of those systems. The N‐oxides (4–6) all exhibit major peaks at M+, (M‐16)+, and (M‐17)+. In addition, 4 shows prominent fragmentations reflecting loss of hydrogen and carbon monoxide. The pathways are related to the geometries of the N‐oxides; deuterated compounds (7–8) aided these assignments.
Rearrangement of tetrazole ethers willi iodide ions
Authors: Vollmar Arnulf , Hassner Alfred
Published: April 2009

O to N Alkyl migration in 1‐aryl‐5‐alkoxytetrazoles was observed on healing the substrates in the presence of sodium iodide. Unlike in similar rearrangements, methyl transfer did not occur in the presence of methyl iodide alone. Solvent effects were also investigated.
Synthesis in the diazasteroid group. III . Syntheses of the 8,16‐ and 8,17‐diazasteroid systems
Authors: Yamazaki Takao , Matoba Katsuhide , Isomura Kazumasa , Nagata Masanori , Castle Raymond N.
Published: April 2009

By using 3‐pyrrolidone derivatives as a source of the D ring, the following five diazasteroids were synthesized: 8,16‐diaza‐2,3‐dimethoxy‐15,15,16‐trimethylgona‐1,3,5(10),13‐tetraen‐12‐one (VII), 8,16‐diaza‐2,3‐dimethoxy‐16‐acetylgona‐1,3,5(10),13‐tetraen‐12‐one (X), 8,17‐diaza‐2,3‐dimethoxy‐17‐acetylgona‐1,3,5(10),13‐tetracn‐12‐one (XI), 8,16‐diaza‐16‐acetylgona‐1,3,5(10), 13‐tetraen‐12‐one (XII), and 8,17‐diaza‐17‐acetylgona‐1,3,5(10),13‐tetraen‐12‐one (XIII).
Pentatomie heteroaromatic cations. Note II. Chemical properties of 2‐phenyl‐1,3‐benzoxathiolium perchlorate
Authors: Degani Iacopo , Fochi Rita , Tundo Piero
Published: April 2009

The reactions of 2‐phenyl‐1,3‐benzoxathiolium perchlorate with common nucleophilic reagents (water, sodium hydroxide, ethanol, thiophenol, morpholine, phenylmagnesium bromide), with reducing agents (zinc, lithium aluminium hydride) and with manganese dioxide, were studied. In every case the reactions proceed by attack of the reagents at the C‐2 position of the cationic system, giving rise either to 1,3‐benzoxathiole derivatives or to ring‐opening products. The 1,3‐benzoxathiolium salts were shown to be suitable intermediates for converting the carboxylic acids into aldehydes and ketones.
Darstellung einiger diazaphenanthrene durch photocyclisierung der benzylidenaminopyridine und pyridinalaniline
Authors: Perkampus H.‐H. , Behjati B.
Published: April 2009

Alle isomeren Benzylidenaminopyridine und Pyridinalaniline wurden nach bekannten Methoden hergestellt. Bei ihrer Bestrahlung mit UV‐Licht in konz. Schwefelsäure konnten sechs Diazaphenanthrene synthetisiert werden. Das Ausbleiben der Photocyclisierung der Benzylidenaminopyridine und Pyridinalaniline in neutralen organischen Lösungsmitteln konnte durch eine der Photocyclisierung vorgelagerte schnelle cis‐trans‐Isomerisierung und durch die nicht planare Gemetric dieser Schiff'schen Basen erklärt werden.
Photolysis and Thermolysis of N‐Alkoxycarbonyl‐α‐diazoamide Acetals
Authors: Graziano M. L. , Scarpati R. , Fattorusso E.
Published: April 2009

In the photoysis and thermolysis of 1‐phenyl‐2,2‐dimethoxy‐2‐(N‐alkoxycarbonylamino)‐diazoethanes the presence of the N‐alkoxyearbonylamino substituent is of fundamental importance. In both cases the carbene intermediate, through intramolecular addition to carbonyl oxygen, gives, as main products, oxazole derivatives. In the thermolysis, especially at relatively low temperature (160°), the diazoamide acetals in part cyclize to form triazole derivatives.
Folic acid analogs. Modifications in the benzene‐ring region. 5. 2′,6′‐diazafolic acid
Authors: Roberts Eugene C. , Shealy Y. Fulmer
Published: April 2009

The synthesis of 2′,6′‐diazafolic acid was accomplished by the condensation of 2‐acetylamino‐4(3H)pteridinone‐6‐earboxaldehyde (XIV) with diethyl N‐[(5‐amino‐2‐pyrimidinyl)carbonyl]‐L‐glutamate (XIII) followed by reduction of the anil double bond and alkaline hydrolylic cleavage of the N2‐acetyl and ethyl ester protecting groups. Intermediate XIII was prepared by starling with 5‐nitro‐2‐styrylpyrimidine (VI) and proceeding via 5‐arnino‐2‐styrylpyrimidine (IX). The henzyloxycarbonyl derivative of IX was prepared and oxidized to the corresponding 5‐benzyloxycarbonylaminopyrimidine‐2‐carboxylic acid (XI). The coupling of XI with diethyl L‐glutamate followed by hydrogenolysis of the henzyloxycarbonyl function afforded the desired intermediate XIII. 2′,6′‐Diazafolic acid was a potent inhibitor of Streptococcus faecium and displayed marginal activity against leukemia 1,1210 in mice.
The effects of lanthanide shift reagents on the NMR spectra of diaza‐and dithiacyclophanes
Authors: Ricci A. , Danieli R. , Phillips R. A. , Ridd J. H.
Published: April 2009

The effect of a lanthanide shift reagent Eu(dpm)3 on the spectra of 3 diazacyclophanes (Ia‐c) has been studied together with the effect of a fluorinated shift reagent En(fod)3d27 on the nmr spectra of three dithiacyclophanes (IIa‐c). The shift reagents remove certain unexpected accidental degeneracies in the original spectra and permit the assignment of the peaks in the expanded spectra to the individual methylene groups. The comparison of the chemical shifts for the methylene groups above the aromatic rings with those of related compounds provides evidence of an upfield shift deriving from the aromatic ring current. The synthesis of two new dithiacyclophanes (IIb‐c) is reported.
Mass spectra of 5‐styryl and 5‐acylpyrazoles
Authors: El Khadem Hassan , Foltz Rodger L. , Horton Derek
Published: April 2009

High‐resolution, electron‐impact, mass‐spectrometric measurements have been made on three types of pyrazoles. Type 1 comprised ethyl 5‐styrylpyrazole‐3‐carboxylates having in the α‐position of the styryl group either a hydrogen atom, a methyl, or a phenyl group. Type II were 1,3,5‐trisubstituted pyrazoles having phenyl (or p‐substituted phenyl) groups in position 1, amide or carboxylate groups in position 3, and styryl (or α‐substituted styryl) groups in position 5. Type III differed from type II in possessing a readily cleaved acyl or aroyl group instead of the styryl group. The compounds containing styryl groups gave significant ions corresponding to the formation of polycyclic heteroaromatic rings, in addition to various other fragments derived from such rings. Intensities and accurate mass‐measurements are given for all ions having intensities exceeding 5% of the base peak.
Mono‐N‐amino salt of benzodiazines and naphthyridines
Authors: Tamura Yasumitsu , Miki Yasuyoshi , Minamikawa Jun‐Ichi , Ikeda Masazunu
Published: April 2009

The mono‐N‐amino salts of 3‐phenylcinnoline, phthalazine, 1‐phenylphthalazine, 4‐phenylquinazoline, 2‐phenylquinoxaline, 1,5‐ and 1,8‐naphthyridines are in high yields prepared by direct N‐amination of the parent heterocycles with O‐mesitylenesulfonylhydroxylamine. With the one expection of 3‐phenylcinnoline, the site of N‐amination was determined by mass and nmr spectral techniques. The results indicate that the N‐amination occurs preferentially at the least sterically hindered nitrogen atom.
Glyoxal bishydrazones through facile ring cleavage of hydrazinopyrazine by hydrazines
Authors: Tserng Kou‐Yi , Bauer Ludwig
Published: April 2009

The reaction of chloropyrazine and hydrazine was reinvestigated and was shown to produce hydrazinopyrazine and glyoxal bishydrazone. The latter was obtained also when hydrazine hydrochloride was allowed to react with Hydrazinopyrazine. The fusion of hydrazinopyrazine at 160° produced glyoxal his(pyrazinythydrazone). The interconversions of glyoxal bishydrazone with Hydrazinopyrazine were studied. Mechanisms to explain the various transformations are discussed.
Competitive and consecutive eliminations of N2 and CO (or C2H4) from some heterocyclies under electron impact
Authors: Tou James C.
Published: April 2009

High resolution mass spectrometry was used to study two types of expected primary competing reactions triggered by two isobaric structural groups in some heterocyclic compounds, I‐V, under 70 eV electron impact. The reactions are

In both cases, it was found that the primary loss was exclusively a N2 molecule which is then followed by the loss of CO or C2 H4.
(1‐Adamantanethio)pyridines and tetrahydropyridines from the reaction of 1‐adamantanethiol with pyridine I‐oxide in acetic anhydride
Authors: Mikrut Bernard A. , Khullar Krishan K. , Chan Pamela Y. P. , Kokosa John M. , Bauer Ludwig , Egan Richard S.
Published: April 2009

The reaction of pyridine 1‐oxide with 1‐adamantanethiol in acetic anhydride produced a mixture of 2‐ and 3‐(1‐adamantanethio)pyridines, 1‐aeetyl‐2‐(1‐adamantanethio)‐3‐hydroxy‐4‐acetoxy‐1,2,3,4‐telrahydropyridine and the corresponding 3‐acetoxyderivative. Pure substances were separated by means of column chromatography on alumina. The tetrahydropyridines were identified by means of their proton magnetic and mass spectra. 4‐(1‐Adamantanethio)pyridine was synthesized from 4‐chloropyridinc and 1‐adamantanethiol. The three isomeric (1‐adamantanethio)‐pyridines were, each, cleaved by concentrated hydrochloric acid to give 1‐chloroadamantane and the corresponding pyridinethiol.
The reaction of propane sultone with cuanosine, adenosine, and related compounds
Authors: Goldschmidt B. M. , Frenkel K. , Van Duuren B. L.
Published: April 2009

Propane sultone (3‐hydroxypropanesulfonic acid‐γ‐lactone) which is a monofunctional directacting alkylating carcinogen, has been shown to react irreversibly with DNA from various sourcesin vitro.It reacts with guanosine in DMSO to yield the N‐7 alkyl nucleoside, while reaction with 2′‐deoxyguanosine yields the corresponding N‐7 alkyl purine. Evidence for the structure of these products and of one formed when adenosine and propane sultone react is presented.
Enamines derived from the reactions of 2‐amino‐3‐(o‐bromobenzyloxy)pyridine with esters of acetoacetic and β‐aminocrotonic acids. Enamines as intermediates in the formation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones
Authors: Yale Harry L.
Published: April 2009

Two stable crystalline enamines, 10 and 11, have been isolated from the reactions of 2‐amino‐3‐(o‐bromobenzyloxy)pyridine, 4, with esters of acetoacetic or β‐aminocrotonic acids. The formation of 10 and 11 occurred in the absence of a solvent or in diethylbenzene at 100–175°, and was always accompanied by the formation of the cyclized derivative, 9‐(o‐bromobenzyloxy)‐2‐methylpyrido[1,2‐a]pyrimidin‐4‐one, 12. Molecular models, ir, and pmr spectra were employed to establish the structure of the enamines and to demonstrate that in solution, 10 and 11 existed as six‐membered chelate structures, with intramolecular hydrogen bonding between the NH proton and the ester carbonyl oxygen atom. The thermal cyclization of 10 and 11 to 12 occurred under a variety of conditions: (a) in diethylbenzene at 170–175°, (b) fusion at 175–180° under atmospheric pressure, or (c) heating at 175–180°/1 mm, thus suggesting that an enamine is the intermediate in cyclization reactions that lead to the formation of pyrido [1,2‐a]pyrimidin‐4‐ones.
Pyridazines. VI. Some 6‐substituted 3(2H)pyridazinones
Authors: Steck Edgar A. , Brundage R. Pauline , Fletcher Lynn T.
Published: April 2009

A series of 6‐substituted 3(2H)pyridazinones was prepared. The 6‐substituent was either aromatic of heter‐aromatic in structure. A few basically‐substituted representatives were also made.
Ring closure, of 2‐benzylamino‐1‐phenylethanols to 4‐phenyltetrahydroisoquinolines
Authors: Schwan Thomas J. , Lougheed Guy S. , Burrous Stanley E.
Published: April 2009

The, facile preparation of 4‐pbenyltetrabydroisoquinolines by the acid‐catalyzed cyclization of 2‐benzylamino‐1‐pbenyletbanols and related compounds is described along with a discussion of the scope, limitations, and possible mechanism of the reaction.
Nucleophilic displacement of aromatic fluorine, Part II Indazoles, indazolo[2,3‐c]quinazolines, indazolo[2,3‐d] [1,4]benzodiazepines and indazolo[2,3‐c]benzo‐1,2,3‐triazenes
Authors: Walser A. , Zally W. J. , Fryer R. Ian
Published: April 2009

3‐(2‐Arninophenyl)indazoles 2 were prepared by the reaction of the o‐fluorobenzophenones 1 with hydrazines. These indazoles were converted to the tetracyclic title compounds by conventional methods.
Synthesis of substituted 5‐oxo‐1‐thiocarbamoyl‐3‐pyrazoline‐4‐alkanoic acid derivatives
Authors: Santilli Arthur A. , Hofmann Bruce R. , Kim Dong H.
Published: April 2009

Cyclization of the 4‐methyl‐3‐thiosemicarbazone of diethyl acetylsuccinate (1a) by the action of ammonium hydroxide followed by acidification afforded ethyl 3‐methyl‐1‐methylthiocarbamoyl‐5‐oxo‐3‐pyrazoline‐4‐acetate (11a). Pmr spectral analyses using shift reagent, Eu(fod)3, in deuteriochloroform indicated the presence also of approximately 15% of a second tautomer, ethyl 5‐hydroxy‐3‐methyl‐1‐(methylthiocarbamoyl)pyrazole‐4‐acetate (11a'). 3‐Methyl‐1‐methyl‐thiocarbamoyl‐5‐oxo‐pyrazoline‐4‐acetamide (11b) was prepared by extending the reaction time of 1a with ammonium hydroxide. Alkaline hydrolysis of 11a provided the corresponding acid 3‐methyl‐1‐methylthiocarbamoyl‐5‐oxo‐3‐pyrazoline‐4‐acetie acid (11c). Regeneration of 11a was achieved by the reaction of ethyl 3‐methyl‐5‐oxo‐3‐pyrazoline‐4‐acetate (IV) with methyl isothiocyanate. The latter reaction provided confirmation of structure for 11a. The preparation of other pyrazolin‐5‐ones by cyclization of thiosemicarbazones of ethyl formylsuccinate and ethyl acetylglutarate also is presented. All spectra are in accord with the proposed structures.
Nucleophilic displacement of aromatic fluorine, part I, synthesis of benzisoxazoles
Authors: Walser Armin , Flynn Thomas , Fryer R. Ian
Published: April 2009

The quinazoline 3‐oxides 2 were found to convert to the benzisoxazoloquinazolines 3 by heating in acetic anhydride. The dihydroquinazoline 3‐oxides 1 underwent aromatization to 4 under the same conditions. Hydrolysis of 3 or 2 led to the 3‐(2‐aminophenyl)benzisoxazoles 8 which could be rearranged to the 3‐(2‐hydroxyphenyl)indazoles 11 by treatment with hydride. Possible mechanisms are discussed.
The ultraviolet spectra of the chloropyridines and chlorinated pyridines possessing a sulfur (‐SR), nitrogen (‐NR2), or oxygen (‐OR) substituent in either the 2 or 4‐position: A convenient method for distinguishing such positional isomers
Authors: Giacobbe Thomas J. , Mcgregor Stanley D. , Beman Floyd L.
Published: April 2009

The ultraviolet spectra for a series of 15 chlorinated pyridines which contain a sulfur, nitrogen or an oxygen substituent at either the 2 or 4‐position have been examined. A correlation has been established between the position (2 vs 4) of the S, N, or O substituent on the chlorinated pyridines and their ultraviolet spectra. It was found that the chlorinated pyridines with S, N, or O substitution at the 2‐position gave ultraviolet spectra whose longest wavelength absorption maxima were enhanced (moved to a greater wavelength and an increased extinction coefficient) when compared to the spectra of the 4‐substituted isomers. The difference is great enough so that an easy identification of positional isomers can be made with a relatively high degree of confidence even when only one positional isomer is available. The ultraviolet spectra of all the chlorinated pyridines has been recorded, and it was observed that the number of chlorine atoms, and not their position, was the more significant factor in determining the overall character of the spectra.
Substituted macrocyclic aryl tetraethers
Authors: Gilbert Everett E.
Published: April 2009

Macrocyclic ethers have been prepared by reading 1,5 dichloro‐2,4‐dinitrobenzene with various halogenated and alkylated resorcinols and hydroquinones. Electrophilic substitution (nitration, bromination, and sulfonation) of several has been studied, with special emphasis on nitration. Macrocycles derived from the hydroquinones and the 2‐substituted resorcinols are more resistant to substitution than those derived from the 4‐, 5‐, or 6‐substituted resorcinols; possible explanations are given.
Reaction of cis‐3‐bromo‐1,2‐dibenzoylpropene with amines
Authors: Weiss Douglas E. , Cromwell Norman H.
Published: April 2009

The reaction of cis‐3‐bromo‐1,2‐dibenzoylpropene (1) with amines proceeds by means of a substitution‐rearrangement attack to give the 2‐(α‐aminoacetophenonyl)acrylophenones (2). Like similar structures, 2 undergoes further substitution‐rearrangement by amines to give 3‐benzoyl‐5‐phenylpyrroles (5) and an enaminoketone, α‐acetophenonyl‐β‐aminoacrylophenone (3). Competitive with substitution‐rearrangement, amine addition to 2 followed by loss of hydrogen and then water leads to formation of the 3‐benzoyl‐4‐amino‐5‐phenylpyrroles (4). The enaminoketones (3) by contrast with 2 are quite stable. Structure 2 when in polar solvents or in the presence of amines undergoes substitution‐rearrangement to give 3, which can be induced to give the pyrroles (5) when exposed to acid conditions. When neat or in solvents of low polarity, 2 undergoes intermolecular substitution‐rearrangement‐dehydration to give 5 almost exclusively.

A novel addition reaction of 3‐benzoyl‐5‐phenylfuran involving attack by isopropyl‐ or cyclohexylamine provides a quantitative method of synthesizing the appropriate N‐substituted examples of 3 and an efficient method of deriving the corresponding pyrroles (5).
Systèmes aromatiques à 10 électrons π derivés de l'aza‐3a pentalène. XVII. Tautomérie azido/tétrazole dans la série du pyrazole
Authors: Alcalde Ermitas , De Mendoza Javier , Elguero José
Published: April 2009

L'étude par IR et RMN de douze azido‐3 (ou −5) pyrazoles en milieu neutre a montré que la seule forme présente est l'azide. Dans le cas des dérivés N‐acétylés et N‐H c'est l'isomère (tautomère) azido‐3 qui est le plus stable. Les azido‐3 pyrazoles sont les seuls polyazoles pour lesquels on observe en RMN (solvant: DMSO) des couplages entre les protons du cycle et le proton fixé sur l'azote. En milieu Basique, on obtient les anions correspondants aux azido‐3 pyrazoles N‐H: ces anions évoluent lentement, en suivant une cinétique d'ordre I, vers des anions bicycliques dérivés de l'aza‐3a pentalène, les pyrazolo[1,5‐d]tétrazoles. Cette évolution a été suivie par IR et RMN.