bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclin D1 polymorphism (G870A) and risk for esophageal adenocarcinoma
Authors: Casson Alan G. , Zheng Zuoyu , Evans Susan C. , Geldenhuys Laurette , van Zanten Sander Veldhuyzen , Veugelers Paul J. , Porter Geoffrey A. , Guernsey Duane L. 
Published: June 2005

AbstractBACKGROUNDTo investigate individual susceptibility to gastroesophageal reflux disease, Barrett esophagus, and esophageal adenocarcinoma, the authors studied the frequency of the common G870A polymorphism of CCND1, which encodes cyclin D1, a key cell cycle regulatory protein.METHODSThe study population included 307 patients who were enrolled in a prospective case–control study to evaluate lifestyle risk factors and molecular alterations in gastroesophageal reflux disease (n = 126 patients), Barrett esophagus (n = 125 patients), and esophageal adenocarcinoma (n = 56 patients). A control group included 95 strictly asymptomatic individuals. Genomic DNA was extracted from cases and controls, and polymerase chain reaction was used to amplify exon 4 of CCND1. After digestion with BsrI, acrylamide gel electrophoresis was used to identify the wild type and common G870A polymorphic alleles. The frequency of alleles (G/G, G/A, A/A) was compared between cases and controls. Immunohistochemistry was used to study cyclin D1 distribution in among patients in the case group.RESULTSCompared with the asymptomatic control group, and adjusted for age and gender, increasing frequencies were seen for the A/A genotype in patients with gastroesophageal reflux disease (odds ratio [OR], 2.83; 95% confidence interval [95% CI], 1.09–7.34), Barrett esophagus (OR, 3.69; 95% CI, 1.46–9.29), and esophageal adenocarcinoma (OR, 5.99; 95% CI, 1.86–18.96). No association was seen between genotype and cyclin D1 overexpression.CONCLUSIONSThe CCND1 A/A genotype was associated with increased risk for gastroesophageal reflux disease, Barrett esophagus, and esophageal adenocarcinoma. The contribution of this polymorphism to susceptibility of defined stages of progression to esophageal adenocarcinoma suggested potential application in endoscopic Barrett surveillance programs. Cancer 2005. © 2005 American Cancer Society.
Effect of neutropenia on the impact of a cognitive‐behavioral intervention for symptom management
Authors: Given Barbara A. , Given Charles W. , Jeon Sanchoon , Sikorskii Alla 
Published: June 2005

AbstractBACKGROUNDTrials of cognitive‐behavioral interventions (CBI) designed to reduce symptom severity or improve dimensions of quality of life seldom consider how the side effects of treatment or the complications imposed by the disease or treatment may moderate the impact of the trial on the designated outcome. To address this issue, the moderating effect of neutropenia on the impact of a CBI for reducing symptom severity was evaluated among patients with cancer undergoing chemotherapy.METHODSThe authors described the impact of a randomized trial of a 10‐contact, 20‐week CBI on symptom severity, as well as the moderating effect of a neutropenic episode on symptom severity at 20 weeks. Severity scores were based on sum scores (0–10) for 15 symptoms.RESULTSThere was an effect for age (younger) and group on severity at 20 weeks and an interaction between neutropenia and group. Among patients with no evidence of neutropenia, those in the experimental arm had a 9‐point lower severity score at 20 weeks. Among patients who experienced neutropenia, differences in symptom severity by arm of the trial were < 3 points. Further, fatigue, fever, and pain were more prevalent among patients with neutropenia.CONCLUSIONSPatients who experienced neutropenia did not benefit from a CBI to lower symptoms. The overall effect of this intervention came almost exclusively from patients without neutropenia. Cancer 2005. © 2005 American Cancer Society.
Adsorption of [D2]Methanol on Ru(001)O Surfaces: The Influence of Preadsorbed Oxygen on the Methoxide Geometry
Authors: Barros Ricardo B. , Garcia Ana Rosa , Ilharco Laura M. 
Published: June 2005

AbstractThe influence of oxygen precoverage on the bonding geometry of methoxide on Ru(001) was studied using the isotopically labeled molecule CHD2OH by reflection–absorption infrared spectroscopy (RAIRS). This molecule is an excellent model because the vibrational spectra of CHD2O− may be unambiguously correlated with the adsorption configuration. For Ru(001)O layers with an effective oxygen coverage (θ0) between 0.25 and 0.6 ML (ML=monolayer), the influence of the oxygen precoverage was shown to vary with the initial methanol exposure. For an extremely low dose of [D2]methanol (0.01 L; L=Langmuir, 1 L=10−6 torr s), at 90 K, no oxygen‐coverage effects were detected on the geometry of [D2]methoxide: it adsorbs in an upright orientation (pseudo‐C3v local symmetry), just as on clean Ru(001). An increase in the methanol exposure to 0.1 L, at the same temperature, results in the formation of a disordered layer of tilted methoxide: for θO=0.25 ML, Cs/C1 and intrinsic C1 configurations are present on the surface, whereas for θO≥0.5 ML, only the former species were identified. The thermal activation of these tilted layers to 105 K results in a lower coverage of upright methoxide for any oxygen precoverage, coadsorbed with decomposition products, as confirmed by the detection of adsorbed formaldehyde and, on the denser oxygen layer (θO=0.6 ML), formate. The influence of the oxygen precoverage becomes determinant when annealing a [D2]methanol multilayer to 105 K: for θO=0.25 ML, the RAIR spectrum correlates with a disordered layer of tilted methoxide and formaldehyde, whereas for θO=0.6 ML upright methoxide, formate, and carbon monoxide were identified. On clean Ru(001), for methanol exposures ≥0.1 L, the C3v methoxide configuration was never attained upon thermal activation.
Radiolysis of Confined Water: Molecular Hydrogen Formation
Authors: Rotureau P. , Renault J. P. , Lebeau B. , Patarin J. , Mialocq J.‐C. 
Published: June 2005

AbstractThe formation of molecular hydrogen in the radiolysis of water confined in nanoscale pores of well‐characterised porous silica glasses and mesoporous molecular sieves (MCM‐41) is examined. The comparison of dihydrogen formation by irradiation of both materials, dry and hydrated, shows that a large part of the H2 comes from the surface of the material. The radiolytic yields, G(H2)=(3±0.5)×10−7 mol J−1, calculated using the total energy deposited in the material and the water, are only slightly affected by the degree of hydration of the material and by the pore size. These yields are also not modified by the presence of hydroxyl radical scavengers. This observation proves that the back reaction between H2 and HO. is inoperative in such confined environments. Furthermore, the large amount of H2 produced in the presence of different concentrated scavengers of the hydrated electron and its precursor suggests that these two species are far from being the only species responsible for the H2 formation.Our results show that the radiolytic phenomena that occur in water confined in nanoporous silica are dramatically different to those in bulk water, suggesting the need to investigate further the chemical reactivity in this type of environment.
Is the Aromatic Fragment of Piano‐Stool Ruthenium Compounds an Essential Feature for Anticancer Activity? The Development of New RuII‐[9]aneS3Analogues
Authors: Serli Barbara , Zangrando Ennio , Gianferrara Teresa , Scolaro Claudine , Dyson Paul J. , Bergamo Alberta , Alessio Enzo 
Published: June 2005

AbstractNew half‐sandwich RuII‐[9]aneS3complexes ([9]aneS3= 1,4,7‐trithiacyclononane), namely [RuCl2(PTA)([9]aneS3)] (4), [RuCl(PTA)2([9]aneS3)][OTf] (5), [RuCl(en)([9]aneS3)][OTf] (6), [RuCl(enac)([9]aneS3)][OTf] (7), [RuCl(bipy)([9]aneS3)][OTf] (8), and [Ru(dmso‐S)(bipy)([9]aneS3)][OTf]2(9) [PTA = 1,3,5‐triaza‐7‐phosphaadamantane; enac = 1,2‐bis(isopropyleneimino)ethane; OTf = CF3SO3–] were prepared from Ru‐[9]aneS3–dmso precursors and structurally characterized, both in solution and in the solid state by X‐ray crystallography. Some of them are analogs of known cytotoxic organometallic RuII‐(η6‐arene) and RuII‐(η5‐cyclopentadienyl) compounds, in which the aromatic fragment is replaced by the sulfur macrocycle 1,4,7‐trithiacyclononane, while the rest of the coordination sphere is left unchanged. Similarly to the aromatic analogs for which data are available, in aqueous solution the Ru‐[9]aneS3complexes (with the exception of5) hydrolyze a chloride (or a dmso in the case of9) to give the corresponding aquo species. This process is rapidly reversed in the presence of free chloride, and coordination of phosphate is likely to occur to the aquo species in phosphate buffered solutions at physiological pH. Preliminary in vitro tests performed on complexes4–6against the mouse adenocarcinoma cancer cell line (TS/A) and the human mammary normal cell line (HBL‐100) showed that, in general, the Ru‐[9]aneS3compounds have a cytotoxicity comparable to that of the corresponding organometallic analogs. These results suggest that the aromatic fragment of the piano‐stool RuIIcompounds is not an essential feature for the in vitro anticancer activity, and it might be effectively replaced by another face‐capping ligand with a low steric demand, such as [9]aneS3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Stem cell proteomes: A profile of human mesenchymal stem cells derived from umbilical cord blood
Authors: Feldmann Robert E. , Bieback Karen , Maurer Martin H. , Kalenka Armin , Bürgers Heinrich F. , Gross Benjamin , Hunzinger Christian , Klüter Harald , Kuschinsky Wolfgang , Eichler Hermann 
Published: June 2005

AbstractMultipotent mesenchymal stem cells (MSCs) derived from human umbilical cord blood (UCB) represent promising candidates for the development of future strategies in cellular therapy. To create a comprehensive protein expression profile for UCB‐MSCs, one UCB unit from a full‐term delivery was isolated from the unborn placenta, transferred into culture, and their whole‐cell protein fraction was subjected to two‐dimensional electrophoresis (2‐DE). Unambiguous protein identification was achieved with peptide mass fingerprinting matrix‐assisted laser desorption/ionization – time of flight – mass spectrometry (MALDI‐TOF‐MS), peptide sequencing (MALDI LIFT‐TOF/TOF MS), as well as gel‐matching with previously identified databases. In overall five replicate 2‐DE runs, a total of 2037 ± 437 protein spots were detected of which 205 were identified representing 145 different proteins and 60 isoforms or post‐translational modifications. The identified proteins could be grouped into several functional categories, such as metabolism, folding, cytoskeleton, transcription, signal transduction, protein degradation, detoxification, vesicle/protein transport, cell cycle regulation, apoptosis, and calcium homeostasis. The acquired proteome map of nondifferentiated UCB‐MSCs is a useful inventory which facilitates the identification of the normal proteomic pattern as well as its changes due to activated or suppressed pathways of cytosolic signal transduction which occur during proliferation, differentiation, or other experimental conditions.
Fused 1,2‐Dithioles. Part VII
Authors: Stachel Hans‐Dietrich , Zimmer Barbara , Eckl Eduard , Semmlinger Katharina , Weigand Wolfgang , Wünsch Ralf , Mayer Peter 
Published: June 2005

AbstractThe 1,2‐dithiolosultam derivative 14 was obtained from the (α‐bromoalkylidene)propenesultam derivative 9 (Scheme 1). Regioselective cleavage of the two ester groups (→1b or 2b) allowed the preparation of derivatives with different substituents at C(3) in the dithiole ring (see 27 and 28) as well as at C(6) in the isothiazole ring (see 17–21; Scheme 2). Curtius rearrangement of the 6‐carbonyl azide 21 in Ac2O afforded the 6‐acetamide 22, and saponification and decarboxylation of the latter yielded ‘sulfothiolutin’ (30). Hydride reductions of two of the bicyclic sultams resulted in ring opening of the sultam ring and loss of the sulfonyl group. Thus the reduction of the dithiolosultam derivative 14 yielded the alkylidenethiotetronic acid derivative 33 (tetronic acid=furan‐2,4(3H,4H)‐dione), and the lactam‐sultam derivative 10 gave the alkylidenetetramic acid derivative 35 (tetramic acid=1,5‐dihydro‐4‐hydroxy‐2H‐pyrrol‐2‐one) (Scheme 3). Some of the new compounds (14, 22, 26, and 30) exhibited antimycobacterial activity. The oxidative addition of 1 equiv. of [Pt(η2‐C2H4)L2] (36a, L=PPh3; 36b, L=1/2 dppf; 36c, L=1/2 (R,R)‐diop) into the SS bond of 14 led to the cis‐(dithiolato)platinum(II) complexes 37a–c. (dppf=1,1′‐bis(diphenylphosphino)ferrocene; (R,R)‐diop={[(4R,5R)‐2,2‐demithyl‐1,3‐dioxolane‐4,5‐diyl]bis(methylene)}bis[diphenylphosphine]).
Trifluoromethanesulfonic Acid Catalyzed Alkylation of Arenes with Methyl (2R)‐Glycidate
Authors: Linares‐Palomino Pablo J. , Prakash G. K. Surya , Olah George A. 
Published: June 2005

AbstractMethyl (R)‐glycidate (=methyl (R)‐oxiranecarboxylate; 2) in superacidic trifluoromethanesulfonic acid medium reacts with electron‐rich arenes to give α‐hydroxy‐β‐arylpropanoate derivatives 3a–3f with high stereospecificity. At the same time, the observed high regioselectivity has been attributed to superelectrophilic activation of the glycidate.
The exo‐Outstretching Effect Governing the Exclusive Stereoselectivity of the Intramolecular [2+2] Photocycloaddition of Vinylarenes
Authors: Nishimura Jun , Funaki Takashi , Saito Noriaki , Inokuma Seiichi , Nakamura Yosuke , Tajima So , Yoshihara Toshitada , Tobita Seiji 
Published: June 2005

AbstractIntramolecular [2+2] photocycloaddition of a dimeric vinylpyridine 1 through a singlet‐excited species efficiently formed the corresponding syn‐ and anti‐pyridinophanes 2 and 3. The syn‐isomers were elucidated spectroscopically and by X‐ray crystallography as exo,syn‐configured. The high selectivity under formation of exo,syn‐2 was thoroughly investigated. Consequently, an exo‐outstretching effect, which is observed around the periphery of a face‐to‐face‐oriented system between two aromatic nuclei as a transition state, on cyclobutane ring formation was discovered for the first time.
The Reactivity of 2‐Fluoro‐ and 2‐Chloropyridines toward Sodium Ethoxide: Factors Governing the Rates of Nucleophilic (Het)Aromatic Substitutions
Authors: Schlosser Manfred , Rausis Thierry 
Published: June 2005

AbstractThe relative displacement rates of the halide substituent from 2‐fluoro‐ and 2‐chloropyridines by EtONa in EtOH at +25° were assessed by competition kinetics. The 2‐fluoropyridine reacts 320 times faster than the chloro analog. A CF3 group increases the reactivity more than single halogen atoms do, whatever the element, and the latter are superior to Me3Si groups. Substituents accommodated at the 4‐position operate through their inductive effect, whereas at the 3‐position, this action may be attenuated by steric hindrance. Almost all 5‐substituents enhance the rate of the nucleophilic substitution occurring at the 2‐position. The sole exception concerns the F‐atom at the 5‐position which retards the reaction, presumably by lone‐pair/lone‐pair repulsion with the negative charge building up at the central C‐atom of the intermediate Meisenheimer complex. The substituent effects are additive. Therefore, by using the increments derived from the present work, the rates of future reactions should be predictable with fair accuracy.
Benzo[a]heptalenes from Heptaleno[1,2‐c]furans. Part I
Authors: Uebelhart Peter , Weymuth Christophe , Hansen Hans‐Jürgen 
Published: June 2005

AbstractIt is shown that heptaleno[1,2‐c]furans 1, which are available in two steps from heptalene‐4,5‐dicarboxylates by reduction and oxidative dehydrogenation of the corresponding vicinal dimethanols 2 with MnO2 or IBX (Scheme 4), react thermally in a Diels–Alder‐type [4+2] cycloaddition at the furan ring with a number of electron‐deficient dipolarophiles to yield the corresponding 1,4‐epoxybenzo[d]heptalenes (cf. Schemes 6, 15, 17, and 19). The thermal reaction between dimethyl acetylenedicarboxylate (ADM) and 1 leads, kinetically controlled, via a sterically less‐congested transition state (Fig. 4) to the formation of the (M*)‐configured 1,4‐dihydro‐1,4‐epoxybenzo[a]heptalenes, which undergo a cyclic double‐bond shift to the energetically more‐relaxed benzo[d]heptalenes 4 (Schemes 6 and 7). Most of the latter ones exhibit under thermal conditions epimerization at the axis of chirality, so that the (M*)‐ and (P*)‐stereoisomers are found in reaction mixtures. The (P*)‐configured forms of 4 are favored in thermal equilibration experiments, in agreement with AM1 calculations (Table 1). The relative (P*,1S*,4R*)‐ and (M*,1S*,4R*)‐configuration of the crystalline main stereoisomers of the benzo[d]heptalene‐2,3‐dicarboxylates 4a and 4f, respectively, was unequivocally established by an X‐ray crystal‐structure determination (Figs. 1 and 2). Acid‐induced rearrangement of 4 led to the formation of the corresponding 4‐hydroxybenzo[a]heptalene‐2,3‐dicarboxylates 5 in moderate‐to‐good yields (Schemes 8, 13, and 14). When the aromatization reaction is performed in the presence of trifluoroacetic acid (TFA), trifluoroacetates of type 6 and 13 (Schemes 8, 12, and 13) are also formed via deprotonation of the intermediate tropylium ions of type 7 (Scheme 11). Thermal reaction of 1 with dimethyl maleate gave the 2,3‐exo‐ and 2,3‐endo‐configured dicarboxylates 14 as mixtures of their (P*)‐ and (M*)‐epimers (Scheme 15). Treatment of these forms with lithium di(isopropyl)amide (LDA) at −70° gave the expected benzo[a]heptalene‐2,3‐dicarboxylates 15 in good yields (Scheme 16). Fumaronitrile reacted thermally also with 1 to the corresponding 2‐exo,3‐endo‐ and 2‐endo,3‐exo‐configured adducts 17, again as mixtures of their (P*)‐ and (M*)‐epimers (Scheme 17), which smoothly rearranged on heating in dimethoxyethane (DME) in the presence of Cs2CO3 to the benzo[a]heptalene‐2,3‐dicarbonitriles 18 (Scheme 18). Some cursory experiments demonstrated that hex‐3‐yne‐2,5‐dione and (E)/(Z)‐hexa‐3‐ene‐2,5‐dione undergo also the Diels–Alder‐type cycloaddition reaction with 1 (Scheme 19). The mixtures of the stereoisomers of the 2,3‐diacetyl‐1,4‐epoxytetrahydrobenzo[d]heptalenes 22 gave, on treatment with Cs2CO3 in DME at 80°, only mixtures of the regioisomeric inner aldol products 24 and 25 of the intermediately formed benzo[a]heptalenes 23 (Scheme 20).
Synthetic Route to Ergot Alkaloids
Authors: Moldvai István , Temesvári‐Major Eszter , Incze Mária , Dörnyei Gábor , Szentirmay Éva , Szántay Csaba 
Published: June 2005

AbstractRye is sometimes infected by a fungus called Claviceps purpurea. The term ergot designates the dark, brown, tuberous bodies which can be collected before or during harvesting and represent one of the most remarkable drugs of our therapeutic arsenal. Actually, the most significant alkaloids are metabolic products of these fungi. We elaborated three alternative total synthetic pathways to construct the ergoline skeleton, one of which – suitable for scaling up – finally resulted in (+)‐lysergic acid (32a) and α‐ergocryptine (1) (Schemes 5 and 6).
The Thermolysis of the Cycloadducts between Aryl Azides and Hexamethyl‐Dewar‐Benzene Revisited
Authors: Christl Manfred , Lesch Steffen , Deuerlein Stephan , Stalke Dietmar 
Published: June 2005

AbstractThe reactions of 1‐azido‐2,4,6‐trimethyl‐ and 1‐azido‐2,6‐dimethylbenzene with hexamethyl‐Dewar‐benzene (HMDB) give rise to the pentamethyl(iminoethyl)‐4H‐1,2‐diazepines 4 and 5, respectively. The X‐ray crystal‐structure analysis of 5 unequivocally established these unexpected structures, which motivated us to re‐investigate the thermolysis of the adduct 1a of HMDB and azidobenzene. Previously, the triazonine 2 was reported to be the major product, but this interpretation could not be corroborated now, and, instead, the 1‐aminopyrrole 6 was identified as the true compound. The structure of the analogous compound 7, obtained by thermolysis of the (1‐azido‐4‐nitrobenzene)‐HMDB adduct 1b, was confirmed by X‐ray diffraction. In the original literature investigation, a second product had been isolated, in addition to the alleged 2, by chromatographic purificiation of the thermolysis mixture, and structure 3 had been ascribed to it. It turns out now that this compound is not a valence isomer of the major product, but a hydrolysis product, i.e., the ketone 8. The formation of the rather different compounds 4 and 5 on the one hand, and 6 and 7 on the other hand, can be rationalized straightforwardly by a sequence of pericyclic reactions leading to 3H‐1,2‐diazepines 11 as common intermediates, which are converted to either 4 and 5, or 6 and 7, depending on the nature of the aromatic group.
Reversal of Regioselectivity of Nitrone Cycloadditions by Lewis Acids
Authors: Dugovič Branislav , Fišera Lubor , Cyranski Michal K. , Hametner Christian , Prónayová Nada , Obranec Marián 
Published: June 2005

AbstractThe regio‐ and stereoselectivity of cycloadditions of the nitrone 1a and the chiral, sugar‐derived nitrones 13a and 13b with 3‐(prop‐2‐enoyl)‐1,3‐oxazolidin‐2‐one (2) depends on the nature of the Lewis acid catalyst used. Addition of Lewis acid reverses the regioselectivity of the cycloaddition, and improves the anti‐diastereoselectivity in the case of chiral nitrones. The sterically favored isoxazolidin‐5‐yl‐substituted adducts 3, 4, and 14–17 are produced as the major products in the absence of Lewis acid, while the electronically favored regioisomers with isoxazolidin‐4‐yl substituents (5, 6, and 18–21, respectively) are obtained as major products in the [Ti(OiPr)2Cl2] catalyzed reactions. The reactions of nitrone 13b with 2 in the presence of other Lewis acids such as ZnCl2, ZnBr2, ZnI2 and MgI2/I2 gave both regioisomeric pairs of the diastereoisomers, favoring the 4‐substituted congeners. The diastereoisomeric isoxazolidines 3a–6a were reduced with NaBH4 in THF/H2O with subsequent desilylation to yield the separable diols 9–12. Reduction of the diastereoisomeric isoxazolidines 19a and 18a afforded the chiral alcohols 23 and 22, the latter of which was analyzed by X‐ray crystallography.
The Relationship of Cycloaddition Reactions to Spontaneous Vinyl Polymerizations
Authors: Hall Henry K. , Buyle Padias Anne 
Published: June 2005

AbstractThe zwitterionic–biradical tetramethylene proposed by Huisgen as the key intermediate in stepwise [2+2] cycloaddition reactions has been shown to be the crucial intermediate in spontaneous vinyl polymerizations as well. Predominantly biradical tetramethylenes initiate free‐radical copolymerizations, while predominantly zwitterionic tetramethylenes initiate cationic or anionic homopolymerizations. Stepwise cycloaddition is viewed as a spontaneous polymerization lacking a propagation step. These tendencies could be correlated in the form of an ‘organic chemist's Periodic Table’, which has recently been put on a quantitative basis.Huisgen also showed experimentally that [4+2] Woodward–Hoffman‐allowed cycloadditions are completely concerted. Spontaneous copolymerizations accompanying these cycloadditions, therefore, were ascribed to the s‐trans diene form. This concept was given support by kinetics studies, as well as by exclusive cycloaddition from s‐cis cyclopentadiene, and exclusive copolymerization from s‐trans verbenene.
[2+2] Cycloaddition Reactions of Imines with Cyclic Ketenes: Synthesis of 1,3‐Thiazolidine Derived Spiro‐β‐lactams and Their Transformations
Authors: Cremonesi Giuseppe , Dalla Croce Piero , La Rosa Concetta 
Published: June 2005

AbstractUnsymmetric cyclic ketenes were generated from N‐acyl‐1,3‐thiazolidine‐2‐carboxylic acids 1a–c by means of Mukaiyama's reagent, and then reacted with imines 2a–c to the new, isomeric spiro‐β‐lactams 3 and 4 via [2+2] cycloaddition (Staudinger ketene–imine reaction; Scheme 1). The reactions were stereoselective (Table 1) and mainly afforded the spiro‐β‐lactams with a relative trans configuration. The spiro‐β‐lactams could be transformed into the corresponding monocyclic β‐lactams by means of thiazolidine ring opening or into substituted thiazolidines via hydrolysis of the β‐lactam ring.