bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tobacco
Authors: Dhingra Amit , James Victoria A. , Koop Hans U. , Mok Machteld C. , De Paepe Rosine , Gallo Maria , Folta Kevin M. 
Published: March 2009

AbstractJanuary of 1983 was a turning point for plant biotechnology when tobacco was immortalized as a surrogate biological system for testing gene function at a conference on “Advances in Gene Technology: Molecular Genetics of Plants and Animals” hosted by the Miami Winter Symposia series. AlthoughArabidopsishas now become the system of choice for nuclear gene integration due to the ease of transformation and a short generation cycle, tobacco remains the only established system for plastid transformation. This review summarizes the use of tobacco in dissecting plant biology concepts pertaining to the three important compartments of the cell that harbor genetic material within them. Recent studies inN. benthamianahave brought the genus back to the limelight as an outstanding system for transient protein expression. Overall, this chapter also brings out the advantages and limitations of tobacco as a system for discovery in plant biology. As a nonfood and nonfeed crop tobacco retains a remarkable potential for use as a biofactory. Ironically, this genus with a notorious health reputation may prove to be indispensable for the production of medically relevant compounds.
Sex differences in humeral bilateral asymmetry in two hunter‐gatherer populations: California Amerinds and British Columbian Amerinds
Authors: Weiss Elizabeth 
Published: March 2009

AbstractThis study uses two prehistoric Amerindian populations of hunter‐gatherer subsistence patterns to determine whether levels of sexual dimorphism in humeral bilateral cross‐sectional asymmetry are related to sex‐specific differences in activities among these populations. Results confirmed that males of the California Amerind population who engaged in the more unimanual activities of spear hunting and warfare were more asymmetrical than were their female counterparts who engaged in the more bimanual activities of grinding acorns. California Amerind males were also more asymmetrical than British Columbian Amerind males who rowed (using both arms) extensively. Sex differences within British Columbian Amerinds were not statistically significant, nor were female differences between populations. In general, levels of humeral asymmetry appear to be more dependent on sex and population‐specific behaviors rather than broad subsistence patterns. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.
p21WAF1/CIP1 and cancer: A shifting paradigm?
Authors: Gartel Andrei L. 
Published: March 2009

AbstractThe cyclin‐dependent kinase inhibitor p21WAF1/CIP1 is a key mediator of p53‐dependent cell cycle arrest and may play the role of a tumor suppressor in cancer. However, it has been shown that p21 may also act as an oncogene, because it inhibits apoptosis and may promote cell proliferation in some tumors. These data point out to “antagonistic duality” of p21, because it possesses anticancer and procancer properties at the same time. New data suggest that more and more proteins also may play contradictory roles in cancer thus challenging current paradigm of established oncogenes and tumor suppressors. © 2009 International Union of Biochemistry and Molecular Biology, Inc.
A practical near constant bandwidth amplifier
Authors: Maundy Brent , Gift Stephan , Westwick David 
Published: March 2009

AbstractThis paper presents a simple near constant bandwidth amplifier constructed from two operational amplifiers. The near constant bandwidth is obtained by reducing the normally high input impedance of the opamp via local and overall feedback. Experimental results obtained using identical opamps and different opamps verify the expected theoretical results. Copyright © 2009 John Wiley & Sons, Ltd.
Flavonoid consumption and esophageal cancer among black and white men in the United States
Authors: Bobe Gerd , Peterson Julia J. , Gridley Gloria , Hyer Marianne , Dwyer Johanna T. , Brown Linda Morris 
Published: March 2009

AbstractFlavonoids and proanthocyanidins are bioactive polyphenolic components of fruits and vegetables that may account for part of the protective effect of raw fruit and vegetable consumption in esophageal cancer. We studied the relationship between esophageal cancer and dietary proanthocyanidins, flavonoids and flavonoid subclasses (anthocyanidins, flavan‐3‐ols, flavanones, flavones, flavonols and isoflavonoids) using recently developed USDA and Tufts flavonoid and proanthocyanidin databases. The study was a population‐based, case–control analysis of 161 white men with esophageal adenocarcinoma (EAC), 114 white and 218 black men with esophageal squamous cell carcinoma (ESCC) and 678 white and 557 black male controls who lived in 3 areas of the United States. Neither total flavonoid nor proanthocyanidin intake was associated with EAC and ESCC in either white or black men. In white men, inverse associations were observed between anthocyanidin intake and EAC (4th vs. 1st quartile odds ratio [OR], 0.47, 95% confidence interval [CI], 0.24–0.91; ptrend = 0.04) and between isoflavonoid intake and ESCC (4th vs. 1st quartile OR, 0.43, 95% CI, 0.20–0.93; ptrend = 0.01). None of the associations remained significant after adjusting for dietary fiber, which is strongly correlated with flavonoid consumption. We conclude that total flavonoids and proanthocyanidins do not have strong protective effects in either EAC or ESCC. Some protective effects were evident in flavonoid subclasses and population subgroups. In white men, foods rich in anthocyanidins may have chemopreventive effects in EAC and those rich in isoflavonoids may do so in ESCC. © 2009 UICC
Chondrogenic differentiation of mesenchymal stem cells embedded in a scaffold by long‐term release of TGF‐β3 complexed with chondroitin sulfate
Authors: Park Ji Sun , Yang Hyun Jung , Woo Dae Gyun , Yang Han Na , Na Kun , Park Keun‐Hong 
Published: March 2009

AbstractIn this study, mesenchymal stem cells (MSCs) embedded in biodegradable and water‐swollen, elastic block copolymer scaffolds were assessed for MSC chondrogenesis. To determine the optimal conditions for chondrogenesis of the embedded rMSCs, transforming growth factor‐β3 (TGF‐β3) was physically conjugated with chondroitin sulfate (CS) and mixed into scaffolds, which were subsequently evaluated for the differentiation of transplanted rMSCs. In determination of CS‐bound growth factors for chondrogenesis, scaffold mixed with rMSCs and TGF‐β3 was then tested by growth factor release profiles, confocal laser microscopy, RT‐PCR analysis, real time‐QPCR, and histology. The results of several different analyses of the transplanted rMSCs embedded in the scaffolds showed that rMSCs coupled with a CS‐bound TGF‐β3 encapsulated scaffold evidenced superior cartilage tissue formation as measured by an assay of specific gene and protein expression. Moreover, the scaffold exhibited more rapid and more distinct morphology of differentiated rMSCs than was observed with other scaffolds, as determined by histology and immunochemical histology analysis. These results indicate that the elastic block copolymer scaffolds combined with a CS‐bound TGF‐β3 should prove very suitable matrix for cell‐based cartilage tissue engineering. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Long term in vivo degradation and tissue response to photo‐cross‐linked elastomers prepared from star‐shaped prepolymers of poly(ε‐caprolactone‐co‐D,L‐lactide)
Authors: Chapanian Rafi , Tse Man Y. , Pang Stephen C. , Amsden Brian G. 
Published: March 2009

AbstractLong term in vivo degradation, and tissue response to, cylindrical elastomers made of photo‐cross‐linked star‐poly(ε‐caprolactone‐co‐D,L‐lactide) triacrylate were investigated through subcutaneous implantation in rats. The elastomers were prepared via UV initiated crosslinking of prepolymers of equimolar amounts of monomers; a high crosslink density elastomer (ELAST 1250) was prepared from a prepolymer of 1250 Da and a low crosslink density elastomer (ELAST 7800) was prepared from a prepolymer of 7800 Da. The elastomers were characterized using cross‐polarization magic angle spinning solid state 13C NMR and attenuated total reflectance fourier transform infrared spectroscopy. The progress of the in vivo degradation process was followed by employing SEM, uniaxial tensile, mass loss, water uptake, and sol content measurements. The rate of in vivo degradation was faster than the rate of in vitro degradation for both ELAST 1250 and ELAST 7800. Long term in vivo degradation studies indicated that both elastomers undergo bulk hydrolysis along with surface erosion occurring due to the physiological environment. In the case of low cross‐link density elastomers, the onset of mass loss was accompanied with an increase in both water uptake and sol content, whereas, in the case of high crosslink density elastomers, only the water uptake increased. This degradation pattern was due to crazing of the high crosslink density elastomers. ELAST 7800 cylinders were totally degraded, and ELAST 1250 cylinders had lost 80% of their mass, within 30 weeks. Aminor host reaction with minimal vascularity and inflammation was invoked, with a milder tissue response observed with more highly crosslinked cylinders. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Evaluation of self‐expandable, FK506‐coated, covered stents in canine animal model
Authors: Sato Sachiko , Nakayama Yasuhide , Matsuhashi Toshio , Seiji Kazumasa , Matsunaga Kenichi , Takasawa Chiaki , Ishibashi Tadashi , Zhou Yue‐Min , Ishibashi‐Ueda Hatsue , Okamoto Yoshihiro , Asano Hiroyuki , Takahashi Shoki 
Published: March 2009

AbstractThis study aimed to evaluate whether drug coating of the recently developed covered SENDAI stents—self‐expandable stents covered with segmented polyurethane (SPU) films—reduces neointimal thickening in animal model. FK506, which is one of the most effective immunosuppressants, was used. Bare stents; non‐coated, covered stents; and FK506‐coated, covered stents were placed bilaterally in the external iliac arteries of beagle dogs. After 1‐month observation period, angiography did not show significant stent‐induced stenosis. Histological evaluation revealed a completely endothelialized intravascular lumen and the absence of thrombus formation. The area of the intimal thickening induced by the FK506‐coated stents was significantly smaller than that induced by the non‐coated stents, whereas it was larger in the case of both the covered stents than that in the case of the bare stent. In conclusion, FK506 treatment of the self‐expandable, covered stents was confirmed to effectively inhibit intimal thickening, although the SPU film used for covering functioned as a drug carrier in addition to a scaffold for intimal formation. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009
Bone responses to rough titanium implants coated with biomimetic Ca‐P in rabbit tibia
Authors: He Fuming , Yang Guoli , Wang Xiaoxiang , Zhao Shifang 
Published: March 2009

AbstractA new technique to biomimetic deposition calcium phosphate (BDCaP) coating onto rough titanium substrates has been developed recently. This biomimetic deposition technique seems to be promising. It appears to have some advantages such as an inexpensive and simple set‐up, and the possibility to synthesize layers with a defined surface morphology. The aim of this study was to examine the bone responses to BDCaP‐coated implants in a rabbit model. Thirty one implants (16 BDCaP and 15 rough) were inserted into both tibia of 15 rabbits. After 2, 4, and 8 weeks following the implantation, the tibias were retrieved and prepared for histological evaluation. After 2 weeks, BDCaP‐coated implant showed more bone ingrowth inside threads than the rough implants in medullary region (31.43% vs. 24.38%). Histological and quantitative histomorphometrical measurements demonstrated no more bone ingrowth and bone‐implant contact for coated implant as compared with uncoated implant in cortical region at all experiment periods. From the histological viewpoint, the BDCaP coating did not have any positive effect on new bone formation. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009
Synthesis of some 4‐carboxy‐3‐ and 5‐(2‐hydroxyalkyl)pyrazole lactone derivatives
Authors: Gelin Suzanne , Chantegrel Bernard , Deshayes Christian 
Published: March 2009

AbstractThe synthesis and biological activities of some 4‐oxo‐1‐or‐2‐substituted 1H‐or‐2H‐pyrano[4,3‐c]pyrazole derivatives are described.
Diphenyl cyanocarbonimidate. A versatile synthon for the construction of heterocyclic systems
Authors: Webb R. Lee , Labaw Clifford S. 
Published: March 2009

AbstractA simple high yield synthesis of diphenyl cyanocarbonimidate is reported. This synthon may be used to prepare functionalized benzimidazoles, benzoxazoles and triazoles in good yield under mild conditions.
Selenium heterocycles. XXXV . Synthesis and pyrrolysis of aryloxy‐, arylthio‐, and arylseleno‐1,2,3‐selenadiazoles
Authors: Shafiee A. , Toghraie S. , Aria F. , Mortezaei‐Zandjani G. 
Published: March 2009

AbstractA series of 4‐substituted‐5‐arylthio‐1,2,3‐selenadiazoles, 4‐substituted‐5‐arylseleno‐1,2,3‐selenadiazoles and 4‐aryloxymethyl‐1,2,3‐selenadiazoles were synthesized. Pyrrolysis of these compounds afforded the corresponding acetylenes XI, XIII (X = S, Se) and XII, respectively. Oxidation of 4‐substituted‐5‐arylthio‐1,2,3‐selenadiazoles (XIV) with m‐chloroperbenzoic acid gave 4‐substituted‐5‐arylsulfinyl‐1,2,3‐selenadiazoles (XV) and 4‐substituted‐5‐arylsulfonyl‐1,2,3‐selenadiazoles (XVI).
A New Synthesis of 4‐(Alkyl)aminopteridines
Authors: Hara Hiroshi , Van Plas Henk C. Der 
Published: March 2009

AbstractOn treatment of pteridine with potassium permanganate in liquid ammonia, 4‐aminopteridine is obtained in good yield. The C4 σ adduct 4‐amino‐3,4‐dihydropteridine is the intermediate species. Similarly, 2‐chloropteridine undergoes amination at C4, yielding 4‐amino‐2‐chloropteridine; thus no replacement of the chloro atom occurs. By this amination‐oxidation procedure 4‐ethylaminopteridine and its 2‐chloro derivatives are also easily obtained.
A novel synthesis of 1H‐pyrrole‐2,3,4,5‐tetracarboxylates
Authors: Zaima Tadataka , Matsunaga Yoshiharu , Mitsuhashi Keiryo 
Published: March 2009

AbstractA novel and convenient synthesis of 1H ‐pyrrole‐2,3,4,5‐tetracarboxylates is described. Photocyclization of 1,1′‐bis(methoxycarbonyl)divinylamine with acetylenedicarboxylates gave 7‐azabicyclo[2.2.1]hept‐2‐ene‐1,2,3,4‐tetracarboxylates 2a‐i, which on melting split ethylene off to yield 1H‐pyrrole‐2,3,4,5‐tetracarboxylates 3a‐i quantitatively.
On the amination of 3‐nitro‐1,8‐naphthyridines
Authors: Wozniak Marian , Van Der Plas Henk C. , Van Veldhuizen Beb 
Published: March 2009

AbstractA number of 3‐nitro‐2‐X‐1,8‐naphthyridines (X = H,Cl,NH2,OEt) were successfully aminated into the corresponding 4‐amino‐3‐nitro‐2‐X‐naphthyridines, using liquid ammonia and potassium permanganate as reagents. 4‐Amino‐1,4‐dihydro‐3‐nitro‐2‐X‐1,8‐naphthyridines are the actual species being oxidized by the potassium permanganate; their existence has been by 1H nmr spectroscopy.
Chemistry of 5‐pyrimidinecarboxaldehydes
Authors: Bell Lawrence , McGuire H. Michael , Freeman G. Andrew 
Published: March 2009

AbstractSelective hydrolysis of 2‐amino‐4,6‐dichloro‐5‐pyrimidinecarboxaldehyde, 2, gave 2‐amino‐4‐chloro‐1,6‐dihydro‐6‐oxo‐5‐pyrimidinecarboxaldehyde, 5. The oxime of 2 rearranged to 2‐amino‐4‐chloro‐1,6‐dihydro‐6‐oxo‐5‐pyrimidinecarbonitrile, 8. Reaction of 8 with 4‐phenylbutylamine resulted in the displacement of the 4‐chloro atom to give compound 9. Hydrolysis of the cyano function of 9 gave amides 12, 13, and 14 depending on reaction conditions. A discussion of the 1H‐nmr spectrum of 2‐amino‐1,6‐dihydro‐6‐oxo‐4‐[(4‐phenylbutyl)amino]‐5‐ pyrimidinecarboxaldehyde, 6, is presented.
Synthesis and mass spectral fragmentation of 2‐methylthio‐7‐(p‐R‐phenyl)‐8‐phenoxy‐4,5‐benzo‐3‐aza‐2‐nonem. III
Authors: Cortés E. , Martínez R. 
Published: March 2009

AbstractA series of new 2‐methylthio‐7‐(p‐R‐phenyl)‐8‐phenoxy‐4,5‐benzo‐3‐aza‐2‐nonem, IIIa, have been synthesized by regiospecific cycloaddition of phenoxyacetyl on to 2‐methylthio‐4‐(p‐R‐phenyl)‐3H‐1,5‐benzodiazepines IV. The structure was established by ir, 1H‐nmr and ms spectral data together with 13C‐nmr spectral data of desulfurization products, VIa. Likewise, a study has been made of the fragmentation upon electron impact of IIIa and IV. All the spectra analyzed contain molecular ions and the principal fragmentation routes takes place either from the molecular ion or from m/e (M+ — 134) ion. This ion is the base peak for all the compounds analyzed.
Synthesis of phenyl‐substituted 2H‐3,4‐dihydro‐3‐aminomethyl‐1,4‐benzoxazines. Intermediates for 1H‐2,3,3a,4‐tetrahydroimidazo[5,1‐c][1,4]benzoxazin‐1‐one derivatives. Part II
Authors: Banzatti Carlo , Heidempergher Franco , Melloni Piero 
Published: March 2009

AbstractThe synthesis of 2H‐3, 4‐dihydro‐3‐aminomethyl‐1, 4‐benzoxazines substituted by one phenyl group in the 2, 3 or α‐position is reported. The two diastereoisomers of the 2‐phenyl‐derivative were independently synthesized from ethyl trans‐3‐phenylglycidate by a stereospecific route. A previous attempt at the synthesis of these same compounds gave rise to an unexpected aliphatic‐aromatic ketone rearrangement.
Synthetic studies on potential metabolites of carcinogenic aza aromatic hydrocarbons. Part II. Non‐k‐region oxidised and reduced derivatives of 7‐methylbenz[c]acridine
Authors: Lap Bui Vinh , Boux L. J. , Cheung H. T. A. , Holder G. M. 
Published: March 2009

AbstractTwo phenolic derivatives of the weakly carcinogenic aza aromatic hydrocarbon 7‐methylbenz[c]acridine were prepared as reference compounds for studies of the mammalian metabolism of the carcinogen. Also, 1, 2, 3, 4‐ and 8, 9, 10, 11‐tetrahydro‐7‐methylbenz[c]acridine were made as intermediates for synthetic studies directed toward preparation of dihydrodiols of 7‐methylbenz[c]acridine.
Heterocycles from nitrile oxides. I. 5‐imino‐Δ2 ‐1,4,2‐oxathiazolines
Authors: Hussein Ahmed Q. , El‐Abadelah Mustafa M. , Sabri Wail S. 
Published: March 2009

AbstractThe reaction of some arylnitrile oxides with potassium thiocyanate in acetone at ambient temperature, has been investigated. Those having para‐ or meta‐halo (or nitro)substituents give 3‐aryl‐5‐imino‐Δ2‐1,4,2‐oxathiazolines as stable cycloadducts. ortho‐Substitutionn, on the other hand, led directly to the corresponding 5‐ (carbamido) imino analogues. The structures of these new heterocycles are supported by elemental analyses and spectral data.
The structure of sulfonium ylides stabilized by the malonylide moiety
Authors: Galloy J. , Watson W. H. , Craig D. , Guidry C. , Morgan Michael , Mckellar Robert , Ternay A. L. , Martin G. 
Published: March 2009

AbstractThe crystal structures of four thioxanthenium bis(carbomethoxy)methylides and methylides of di‐(p‐nitro‐phenyl)sulfonium and dimethylsulfonium have been determined. The carbanion moiety in all cases is planar and the pi‐system is rotated 90° with respect to the sulfur lone pair. All compounds exhibit a pseudo‐equatorial orientation of the carbanion system except for the 2,4‐dimethylthioxanthenium ylide. The compounds are described in terms of the geometries around the sulfur atom, the interplanar angles and sulfur‐oxygen and oxygen‐oxygen interactions. Surprisingly, the sulfur atom is not symmetrically placed with respect to the two phenyl rings in the thioxanthenium compounds. The sulfur is coplanar with one phenyl ring but is significantly out of the plane of the other. The 13C and 1H spectra of the ylides are discussed along with the temperature dependence which indicates restricted rotation about the +SC− bond in several cases. The factors contributing to the stability of the ylides are analyzed.
Synthesis of 1H,3H‐imidazo[1,5‐c]thiazole‐5,7‐[6H,7aH]‐dione and 7,8‐dihydro‐5‐H‐imidazo[1,5‐c][1,3]thiazine‐1,3‐[2H,8aH]‐dione and derivatives
Authors: Lalezari I. , Seifter S. , Thein A. 
Published: March 2009

Abstract1H,3H‐Imidazo[1,5‐c]thiazole‐5,7‐[6H,7aH]‐dione and the corresponding 7‐thione derivatives as well as 7,8‐dihydro‐5H‐imidazo[1,5‐c][1,3]thiazine‐1,3‐[2H,8aH]‐dione and the corresponding 3‐thione derivatives were synthesized starting from L‐cysteine and DL‐homocysteine thiolactone, respectively. The second group of bicyclic compounds represents a new heterocyclic ring system. The structures of the compounds were confirmed by spectroscopic studies and elemental analyses.
Synthesis of 5H‐pyrazolo[5,1‐c][1,4]benzodiazepine
Authors: Cecchi Lucia , Filacchioni Guido 
Published: March 2009

AbstractThe reaction of 2‐nitrobenzyl bromide with dimethyl pyrazole‐3, 5‐dicarboxylate gave dimethyl 1‐(2‐nitrobenzyl)pyrazole‐3, 5‐dicarboxylate which through a few steps procedure afforded the key intermediate 5, 10‐dihydro‐11‐oxopyrazolo[5, 1‐c][l, 4]benzodiazepine. The latter was reduced and dehydrogenated to yield the new tricyclic system 5H‐pyrazolo[5, 1‐c][1, 4]benzodiazepine.
Nucleophilic substitution by 3‐amino‐1,2‐propanediol in nitropyrazines and nitroquinoxalines
Authors: Hartman George D. , Schwering John E. 
Published: March 2009

AbstractTreatment of 2‐chloro‐3‐nitropyrazine and 2‐chloro‐5‐nitropyrazine with 3‐amino‐1, 2‐propanediol affords products derived from displacement of chloride, while similar reaction of methyl 3‐nitropyrazinoate and 2‐chloro‐3‐nitroquinoxaline gives clean nitro group replacement. Analogous reaction of methyl 6‐chloro‐3‐nitropyrazinoate affords a mixture containing products derived from competitive displacement of chloride and nitrite.
Reaction of 2‐acetamido‐3,7‐dihydropyrrolo[2,3‐d]pyrimidin‐4‐one with dimethylamine and formaldehyde. Formation of two isomeric mannich bases
Authors: Benghiat Eric , Crooks Peter A. 
Published: March 2009

Abstract2‐Acetamido‐3, 7‐dihydropyrrolo[2, 3‐d)pyrimidin‐4‐one reacts with dimethylamine and formaldehyde in glacial acetic acid to afford the two isomeric Mannich products, 2‐acetamido‐3, 7‐dihydro‐5‐dimethylamino‐methylpyrrolo[2, 3‐d]pyrimidin‐4‐one, and 2‐acetamido‐3, 7‐dihydro‐6‐dimethylaminomethylpyrrolo[2, 3‐d]‐pyrimidin‐4‐one, in a ratio of 3:1, respectively.
Synthesis and characterization of 5H‐1,3‐dioxolo[4,5‐f]indoleethylamines
Authors: Grotjahn Douglas B. 
Published: March 2009

AbstractTwelve new N, N‐dialkylated‐5, 6‐methylenedioxytryptamines and N‐cyclopropyl‐5, 6‐methylenedioxytrypt‐amine were prepared as hybrids of known psychoactive phenylethylamines and tryptamines. Novel, more convenient syntheses of N‐methyl‐ and N‐benzylcyclopropylamine are described.
Synthesis of some substituted pyrido[1,2‐a]pyrimidin‐4‐ones and 1,8‐naphthyridines
Authors: Ferrarini Pier Luigi , Mori Claudio , Livi Oreste , Biagi Giuliana , Marini Anna Maria 
Published: March 2009

AbstractThe substituted 4H‐pyrido[1, 2‐a]pyrimidin‐4‐ones (I) were obtained by the condensation of substituted 2‐aminopyridines with δ‐ketocarboxylic esters in PPA. Some of the derivatives I were transformed into the corresponding 1, 8‐naphthyridines II and III.
Synthesis of 6‐methoxy‐2,2‐dimethyl‐2H‐1‐benzothiopyran and 6,7‐dimethoxy‐2,2‐dimethyl‐2H‐1‐benzothiopyran, sulfur analogues of precocene I and precocene II
Authors: Camps F. , Colomina O. , Coll J. , Messeguer A. 
Published: March 2009

AbstractPreparation of title compounds 5, sulfur analogues of the natural insect antijuvenile hormones precocene I and II, is described. The synthetic pathway involves conversion of the appropriate thiophenol 2 into the corresponding thiochroman‐4‐one 4 followed by reduction and dehydration. The 13C nmr data for all the above products are also reported.