bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel approach to measure the contribution of matrix metalloproteinase in the overall net proteolytic activity present in synovial fluids of patients with arthritis
Authors: Simard Nathalie , Boire Gilles , de Brum-Fernandes Artur J , St-Pierre Yves 
Published: July 2006

AbstractDespite decades of research, only a very limited number of matrix metalloproteinase (MMP) inhibitors have been successful in clinical trials of arthritis. One of the central problems associated with this failure may be our inability to monitor the local activity of proteases in the joints since the integrity of the extracellular matrix results from an equilibrium between noncovalent, 1:1 stoichiometric binding of protease inhibitors to the catalytic site of the activated forms of the enzymes. In the present work, we have measured by flow cytometry the net proteolytic activity in synovial fluids (SF) collected from 95 patients with osteoarthritis and various forms of inflammatory arthritis, including rheumatoid arthritis, spondyloarthropathies, and chronic juvenile arthritis. We found that SF of patients with inflammatory arthritis had significantly higher levels of proteolytic activity than those of osteoarthritis patients. Moreover, the overall activity in inflammatory arthritis patients correlated positively with the number of infiltrated leukocytes and the serum level of C-reactive protein. No such correlations were found in osteoarthritis patients. Members of the MMP family contributed significantly to the proteolytic activity found in SF. Small-molecular-weight MMP inhibitors were indeed effective for inhibiting proteolytic activity in SF, but their effectiveness varied greatly among patients. Interestingly, the contribution of MMPs decreased in patients with very high proteolytic activity, and this was due both to a molar excess of tissue inhibitor of MMP-1 and to an increased contribution of other proteolytic enzymes. These results emphasize the diversity of the MMPs involved in arthritis and, from a clinical perspective, suggest an interesting alternative for testing the potential of new protease inhibitors for the treatment of arthritis.
Epratuzumab (humanised anti-CD22 antibody) in primary Sjögren's syndrome: an open-label phase I/II study
Authors: Steinfeld Serge D , Tant Laure , Burmester Gerd R , Teoh Nick KW , Wegener William A , Goldenberg David M , Pradier Olivier 
Published: July 2006

AbstractThis open-label, phase I/II study investigated the safety and efficacy of epratuzumab, a humanised anti-CD22 monoclonal antibody, in the treatment of patients with active primary Sjögren's syndrome (pSS). Sixteen Caucasian patients (14 females/2 males, 33–72 years) were to receive 4 infusions of 360 mg/m2 epratuzumab once every 2 weeks, with 6 months of follow-up. A composite endpoint involving the Schirmer-I test, unstimulated whole salivary flow, fatigue, erythrocyte sedimentation rate (ESR), and immunoglobulin G (IgG) was devised to provide a clinically meaningful assessment of response, defined as a ≥20% improvement in at least two of the aforementioned parameters, with ≥20% reduction in ESR and/or IgG considered as a single combined criterion. Fourteen patients received all infusions without significant reactions, 1 patient received 3, and another was discontinued due to a mild acute reaction after receiving a partial infusion. Three patients showed moderately elevated levels of Human anti-human (epratuzumab) antibody not associated with clinical manifestations. B-cell levels had mean reductions of 54% and 39% at 6 and 18 weeks, respectively, but T-cell levels, immunoglobulins, and routine safety laboratory tests did not change significantly. Fifty-three percent achieved a clinical response (at ≥20% improvement level) at 6 weeks, with 53%, 47%, and 67% responding at 10, 18, and 32 weeks, respectively. Approximately 40%–50% responded at the ≥30% level, while 10%–45% responded at the ≥50% level for 10–32 weeks. Additionally, statistically significant improvements were observed in fatigue, and patient and physician global assessments. Further, we determined that pSS patients have a CD22 over-expression in their peripheral B cells, which was downregulated by epratuzumab for at least 12 weeks after the therapy. Thus, epratuzumab appears to be a promising therapy in active pSS, suggesting that further studies be conducted.
Extrapulmonary manifestations of severe respiratory syncytial virus infection – a systematic review
Authors: Eisenhut Michael 
Published: July 2006

Abstract
Introduction
Respiratory syncytial virus (RSV) bronchiolitis is the most important cause for admission to the paediatric intensive care unit in infants with lower respiratory tract infection. In recent years the importance of extrapulmonary manifestations of RSV infection has become evident. This systematic review aimed at summarizing the available evidence on manifestations of RSV infection outside the respiratory tract, their causes and the changes in clinical management required.

Methods
Databases searched were Medline (1950 to present), EMBASE (1974 to present), PubMed and reference lists of relevant articles. Summarized were the findings of articles reporting on manifestations of RSV infection outside the respiratory tract in patients of all age groups.

Results
Extrapulmonary manifestations reported in previous observational studies included cardiovascular failure with hypotension and inotrope requirements associated with myocardial damage as evident from elevated cardiac troponin levels (35–54% of ventilated infants), cardiac arrhythmias like supraventricular tachycardias and ventricular tachycardias, central apnoeas (16–21% of admissions), focal and generalized seizures, focal neurological abnormalities, hyponatraemia (33%) associated with increased antidiuretic hormone secretion, and hepatitis (46–49% of ventilated infants). RSV or its genetic material have been isolated from cerebrospinal fluid, myocardium, liver and peripheral blood.

Conclusion
The data summarized indicate a systemic dissemination of RSV during severe disease. Cerebral and myocardial involvement may explain the association of RSV with some cases of sudden infant death. In infants with severe RSV infection cardiac rhythm, blood pressure and serum sodium need to be monitored and supportive treatment including fluid management adjusted accordingly.
Functional and phenotypic analysis of human memory CD8+ T cells expressing CXCR3
Authors: Kobayashi Naoki , Kondo Takaaki , Takata Hiroshi , Yokota Shumpei , Takiguchi Masafumi 
Published: July 2006

Abstract
Several chemokine receptors play an important role in the migration of naïve, memory, and effector T cells. Flow cytometric analyses showed that human CD8+ T cells with naïve (CD27+CD28+CD45RA+) or memory (CD27+CD28+/−CD45RA+) phenotypes included a population expressing a high level of CXC chemokine receptor 3 (CXCR3high) and one expressing a low level of it (CXCR3low), but those with the effector phenotype (CD27−CD28−CD45RA+/−) included a population that did not express CXCR3 (CXCR3−) and a CXCR3low population. This relation between the expression level of CXCR3 and memory/effector phenotypes also applied to Epstein-Barr virus- or human cytomegalovirus-specific CD8+ T cells. CXCR3high cells were found predominantly in CC chemokine receptor 7 (CCR7)+CCR5− and CCR7−CCR5− subsets of CD8+ T cells with the CD27+CD28+CD45RA− memory phenotype, suggesting that they are memory cells with intermediate differentiation. Indeed, CXCR3highCD27+CD28+CD45RA−CD8+ T cells had the ability to produce interleukin-2 and interferon-γ. These results together indicate that the expression of CXCR3 is up-regulated on intermediately differentiated memory CD8+ T cells. CXCR3highCD8+ T cells had a greater ability to migrate in response to CXCR3 ligands than CXCR3low ones. As CXCR3high memory CD8+ T cells do not express CCR5, high expression of CXCR3 on these memory CD8+ T cells might play an important role in the migration of these cells to inflammatory sites and in their differentiation.
Habit Modification of a Diastereomeric Salt with an Additive in Optical Resolution
Authors: Sakai Kenichi , Maekawa Yasunari , Saigo Kazuhiko , Sukegawa Makoto , Murakami Hisamichi , Nohira Hiroyuki 
Published: July 2006

Abstract
In the optical resolution of α-methylbenzylamine (1) with mandelic acid (2), the dimeric derivative of 1, bis(α-methylbenzyl)amine (4), caused a habit modification of the diasteromeric salt, (R)-1·(R)-2 (3). The habit modification was strongly influenced by the stereochemistry of 4. Amine (R,R)-4 changed the morphology of the crystal of the diastereomeric salt, even at a concentration of 0.007 mol% of 3; the shape of the crystal became a hexagonal plate from a long hexagonal plate, whereas its stereoisomer ((R,S)-4) changed the morphology less than (R,R)-4, and (S,S)-4 did not change at all. The habit modification of 3 by 4 is discussed on the basis of the crystal growth mechanism while considering the stereochemistry of 4.
Pyrrolizidine Alkaloids. The Synthesis and Absolute Configuration of All Stereoisomers of 4-Carboxy-4-ethyl-3-hydroxy-2-isopropyl-4-butanolide, the Necic Acid Component of Axillaridine
Authors: Matsumoto Takashi , Terao Hiromitsu , Ishizuka Natsuki , Usui Shuji , Nozaki Hiroshi 
Published: July 2006

Abstract
All stereoisomers (4a,b–7a,b) of 4-carboxy-4-ethyl-3-hydroxy-2-isopropyl-4-butanolide, the necic acid component of axillaridine, have been synthesized. Methyl(E)-(S)-(+)-2-ethyl-4-methoxycarbonyl-5-methyl-2- hexenoate (12a) was converted into γ-lactone acids, 4a (2S,3S,4S), 5a (2S,3R,4R), and 5b (2R,3S,4S), by a series of reactions: Epoxidation with m-chloroperbenzoic acid, treatment with acetone in the presence of tin(IV) chloride, acidic hydrolysis with formic acid, and alkaline hydrolysis with barium hydroxide. Similarly, (R)-(−)-enantiomer (12b) was also transformed into γ-lactone acids 4b (2R,3R,4R), 5b and 5a. Subsequently, (E)-(S)-(+)-4-carboxy-2-ethyl-5-methyl-2-hexenoic acid (13a) and its (R)-(−)-enantiomer (13b) were esterified with chloromethyl methyl ether in the presence of triethylamine to give the corresponding bis(methoxymethyl) esters (26a and 26b). Oxidation of 26a with potassium permanganate and subsequent acidic hydrolysis afforded γ-lactone acids, 6a (2S,3R,4S) and 7a (2S,3S,4R). Similarly, ester 26b was also converted into 6b (2R,3S,4R) and 7b (2R,3R,4S). The stereochemical courses of the above-mentioned trans- and cis-hydroxylations of olefinic esters (12a,b and 26a,b) were well explained by applying the Felkin–Anh model. The CD spectra of the synthetic 4a,b–7a,b are also discussed.
Chemical Behavior of Aromatic Radical Cations under Superoxide-Free Electron Transfer Photooxygenation Conditions
Authors: Futamura Shigeru 
Published: July 2006

Abstract
The electron transfer photooxygenations of aromatic compounds were carried out with trityl salts. Under these superoxide-free reaction conditions, only anthracene and 1,1-diarylethylenes were photooxygenated, stilbenes isomerized, and quantitatively recovered were naphthalene, phenanthrene, alkylnaphthalenes, tetraphenylethylene and 1,1,4,4-tetraaryl-1,3-butadienes. The reactivities of their radical cations toward triplet oxygenation were discussed on the basis of the quantum yield measurements and product analyses.
Cycloaddition Reactions of 2-Acetylamino-, 2-Alkylamino-, 8-Ethylamino-, and 8-Acetylamino-1-azaazulenes with Dimethyl Acetylenedicarboxylate
Authors: Abe Noritaka , Fukazawa Yoshimasa , Hirai Yoshimasa , Sakurai Tosio , Urushido Kunio , Kakehi Akikazu 
Published: July 2006

Abstract
The reactions of 2- and 8-(substituted amino)-1-azaazulenes with dimethyl acetylenedicarboxylate (DMAD) were investigated. Treatment of ethyl 2-acetylamino-1-azaazulene-3-carboxylate with DMAD in refluxing acetonitrile gave 9-ethyl 1,2,3-trimethyl 3a-azacyclopent[a]azulene-1,2,3,9-tetracarboxylate, 5-ethyl 1,2,2a,3-tetramethyl 4-acetyl-2a,3-dihydro-4H-4, 10b-diazapentaleno[1,6-aj]azulene-1,2,2a,3,5-pentacarboxylate (3a), and dimethyl (10-ethoxycarbonyl-4-methoxycarbonyl-2,4a-dihydro-2-oxo-2H-1,4a-diazabenz[a]azulen-3-yl)maleate. Compound 3a thermally rearranged to 9-ethyl 2,3,10,11-tetramethyl 1-acetyl-2,3,4,4a-tetrahydro-1H-1,4-diaza-3,4a-ethenofluorene-2,3,9,10,11-pentacarboxylate. The reaction of ethyl 2-alkylamino-1-azaazulene-3-carboxylate with DMAD gave the corresponding 4-alkyl-2a,3-dihydro-4H-4,10b-diazapentaleno[1,6-aj]azulene derivatives, and the etheno-bridged 1-azaheptalene derivative. The reaction of 8-ethylamino-3-phenyl-1-azaazulene with DMAD gave trimethyl 1-phenyl-2a-azabenz[cd]azulene-3,4,5-tricarboxylate, tetramethyl 6-ethyl-1-phenyl-4a,5-dihydro-6H-2a,6-diazapentaleno[1,6-cd]azulene-3,4,4a,5-tetracarboxylate, tetramethyl 3-phenyl-9b-azaindeno[1,6,7-bcd]azulene-1,2,8,9-tetracarboxylate, and dimethyl [8-phenyl-1,2,3-tris(methoxycarbonyl)-8H-3a-azacyclopent[1,2-a]inden-8-yl]maleate. However, the reaction of 8-acetylamino-3-phenyl-1-azaazulene with DMAD gave dimethyl-1-phenyl-2a,5-diazabenz[cd]azulene-3,4-dicarboxylate, trimethyl 3-phenyl-8,9b-diazaindeno[1,6,7-bcd]azulene-1,2,9-tricarboxylate, dimethyl 3-phenyl-8,9b-diazaindeno[1,6,7-bcd]azulene-1,2-dicarboxylate, tetramethyl 6-acetyl-1-phenyl-4a,5-dihydro-6H-2a,6-diazapentaleno[1,6,7-cd]azulene-3,4,4a,5-tetracarboxylate. The structures of the obtained compounds were determined by inspections of their physical and spectral data, and by single-crystal X-ray analyses of some of these compounds. The reaction mechanisms of these reactions are discussed.
Synthesis of Novel Polycyclic Selenepinone Compounds
Authors: Sakakibara Makoto , Mizumoto Takahiro , Watanabe Yoshihiko , Toru Takeshi , Ueno Yoshio 
Published: July 2006

Abstract
Novel polycyclic selenepinone compounds, benzo[b]naphtho[2,3-f]selenepin-6,11,13(12H)-trione (6) and 6,14-dimethoxybenzo[1,2-b:5,4-b′]bis[1]benzoselenepin-12,16(13H,15H)-dione (14) were synthesized from chloroquinones.
Structure of Intramolecular Boron–Amine Complexes and Proposal of Tetrahedral Character for Correlation between Molecular Structure and Barrier to Dissociation of the N–B Bonds
Authors: Toyota Shinji , Oki Michinori 
Published: July 2006

Abstract
The molecular structures of a set of intramolecular boron-amine complexes, 9-[2-(dialkylaminomethyl)phenyl]-9-borabicyclo[3.3.1]nonanes (alkyl = Me and Et) and 2-[2-(dimethylaminomethyl)phenyl]-4,4-diphenyl-1,3,2-dioxaborolane, were determined by the X-ray analyses. The boron atom has a tetrahedral geometry and the five-membered ring is puckered with the nitrogen atom out of the plane in every complex. The distances of the N–B coordination bonds, which are in the range of 1.74–1.77Å, are not always correlated to the barrier to dissociation of the N–B bonds. In order to correlate the molecular structures to the strength of the N–B coordination bonds, the tetrahedral character, which is calculated from bond angles at a boron atom, is proposed. The usefulness as well as the limitation of this parameter are discussed.
Stereoselective Synthesis of (±)-Ireland Alcohol Using Titanium-Mediated [2,3]Wittig Rearrangement Product as a Starting Material
Authors: Ikegami Satoru , Okamura Hiroaki , Kuroda Satoru , Katsuki Tsutomu , Yamaguchi Masaru 
Published: July 2006

Abstract
The synthesis of (±)-Ireland alcohol, a key intermediate for the synthesis of tirandamycin A, was achieved in a straightforward manner by using isopropyl (2R*, 3S*, 4E)-6-benzyloxy-2-hydroxy-3-methyl-4-hexenoate as a starting material, which was readily obtained by the [2,3]Wittig rearrangement of isopropyl [(E)-1-benzyloxymethyl-2-butenyloxy]acetate via its titanium enolate.
One-Pot Synthesis and Redox Properties of Conjugation-Extended 4,4′-Bipyridines and Related Compounds. New Ligands Consisting of a Heterocyclic Three-Ring Assembly
Authors: Takahashi Kazuko , Nihira Takayasu 
Published: July 2006

Abstract
Dipyridyl-substituted heterocycles such as 2,5-di(4-pyridyl)thiophene 3, 2,5-di(4-pyridyl)furan 4, 2,5-di(4-pyridyl)thieno[3,2-b]thiophene 7, 1,4-di(4-pyridyl)benzene 6, 2,5-di(2-pyridyl)thiophene 8, and 2,5-di(3-pyridyl)thiophene 9 have been efficiently synthesized by a simple one-pot procedure through the palladium-mediated cross-coupling reaction between (trimethylstannyl)pyridines and dibromo-substituted heteroaromatics. The spectroscopic data (IR, 1H NMR, 13C NMR, UV) as well as their reduction potentials of these compounds have been determined to evaluate the utility potentials to chelating ligands for metal complexes or to synthetic precursors of viologen-type bipyridinium salts. The conjugation interaction throughout the three rings appears to be more significant in 3 and 4 than in 6. The formation of stable redical anions and dianions of 3 and 4 has been proved by cyclic voltammetry.
Correlation between Positron Annihilation and Gas Diffusion Properties of a Series of Polyimides
Authors: Tanaka Kazuhiro , Katsube Mikio , Okamoto Ken-ichi , Kita Hidetoshi , Sueoka Osamu , Ito Yasuo 
Published: July 2006

Abstract
The lifetime and the intensity of ortho-positronium (o-Ps), τ3 and I3, respectively, were measured for a series of polyimides prepared from 4,4′-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]diphthalic dianhydride. Average size of free space holes probed by o-Ps, υh,Ps, was evaluated from τ3 using an empirical equation. There was a clear correlation between logarithm of diffusion coefficients, , of CO2 and CH4 and υh,Ps for the polyimides. Large differences in among the polyimides having the same fractional free space, VF, were attributed to differences in υh,Ps. There was a fairly good correlation between log and (υh,PsI3)−1, suggesting that I3 is a measure of the concentration of free space holes which can accommodate o-Ps, at least for the polyimides with the similar chemical structure. Correlation between VF and υh,PsI3 was rather poor.
Solvent Extraction of Europium(III) with Benzoylacetone and Benzoyltrifluoroacetone into Carbon Tetrachloride in the Absence and Presence of Tetrabutylammonium Ions
Authors: Noro Junji , Sekine Tatsuya 
Published: July 2006

Abstract
The solvent extraction of europium(III) in 0.1 mol dm−3 sodium nitrate solutions with benzoylacetone (Hbza) or benzoyltrifluoroacetone (Hbfa) in carbon tetrachloride was measured in the absence and presence of tetrabutylammonium ions (tba+). Although extraction with Hbfa occurred at lower pH than with Hbza, the extraction measured as a function of the β-diketonate ion concentration in the aqueous phase was rather similar. It was also found that extraction with Hbfa was greatly enhanced by the addition of tba+, the effect, however, was negligible with Hbza. The data were analyzed from the stand point that the neutral metal chelate, Eu(bfa)3, was extacted into the organic phase and associated with ion-pairs of the reagents, bfa−tba+, in this phase. It was also found that though extraction of ion-pairs of bfa− tba+ occurred, that of bza−tba+ was negligible. Thus, the reason for the negligible extraction of the ternary complex, Eu (bza)4− tba+, was explained in terms of the negligible extraction of the bza−tba+, which might associate with Eu(bza)3 in the organic phase.
Preparation and Stereochemistry of the Mixed-Ligand Complex, Ammine(ethylenediamine)(ethylenediamine-N-acetato)cobalt(III)
Authors: Yasui Takaji , Ama Tomoharu , Kawaguchi Hiroshi , Okamoto Ken-ichi , Hidaka Jinsai 
Published: July 2006

Abstract
Four geometrical isomers for [Co(edma)(NH3)(en)]2+ (edma = ethylenediamine-N-acetate) were prepared for the first time; isomers with the facially chelated edma ligand were optically resolved. Geometrical structures were assigned on the basis of the absorption, 1H NMR, 13C NMR, and CD spectral data; the crystal structure of one of these isomers was determined by an X-ray diffraction method. The crystal is orthorhombic, space group P212121, a = 8.345(1), b = 21.054(2), c = 7.914(1) Å, V = 1390.6(3) Å3, Z = 4, and R = 0.047 for 1985 independent reflections [Fo&gt;3σ(Fo)]. The cobalt atom is octahedrally surrounded by one ammine, the bidentate en, and the facially chelated edma ligands. The ammine ligand occupies the trans position of the secondary nitrogen atom in the edma, trans(Nc, NH3) geometry. This cation, which shows a positive CD sign at 519 nm, takes a ΛΔ configuration around the cobalt atom and an S configuration around the secondary nitrogen atom. The absolute configurations of the other optically active isomers with the facially chelated edma ligand were assigned based on the stereospecific deuteration for the methylene protons of the glycinate ring in the edma ligand in a basic D2O solution.
Comparison of IR-Transmission Method with the Conventional DTA Method (Kissinger Plot ) in the Crystallization Study of Iron Tellurite Glass
Authors: Nishida Tetsuaki , Inoue Satoru , Takashima Yoshimasa 
Published: July 2006

Abstract
IR-transmission spectra of 95TeO2·5Fe2O3 glass piece show a gradual decrease in the transmittance due to the crystallization initiating at the surface and spreading to the bulk. XRD, IR absorption spectra, and 57Fe-Mössbauer spectra show the formation of paratellurite (α-TeO2) and iron tellurite in the glass matrix. Johnson–Mehl–Avrami plot yields the activation energy (Ea) of 2.9 ± 0.3 eV for the crystallization when the crystallized fraction is approximated by the decreased fraction of IR-transmittance. The Ea is identical to the Te–O single bond energy (3.0 eV) obtained from the literature. Kissinger plot of DTA used for the crystallization in the bulk yields Ea of 2.3 eV. These results indicate that the crystallization proceeds in a two- or three-dimensional manner by the diffusion process both in the bulk and at the surface. Ar+-laser irradiation of 95TeO2·5Fe2O3 glass results in a decrease in the IR-transmittance, indicating the “optical memory” effect.
Atropisomerism in Doubly peri-Substituted 9-(2-Methylbenzyl)triptycene Derivatives, 8-Chloro- and 8-Bromo-1,4-dimethyl-9-(2-methylbenzyl)triptycenes
Authors: Yamamoto Gaku , Nemoto Takashi , Ohashi Yuji 
Published: July 2006

Abstract
The 13C dynamic NMR study revealed that 9-(2-methylbenzyl)triptycene has an energy barrier to gear rotation of 11.8 kcal mol−1 (1 cal = 4.184 J). Introduction of substituents at two of the peri-positions was expected to raise the barrier enough for atropisomerism to be realized in this system. Actually, two stable rotational isomers, ap and sc*(9S*), were separately isolated for 8-chloro- (7) and 8-bromo-1,4-dimethyl-9-(2-methylbenzyl)triptycene (8). Classical kinetic studies in toluene-d8 solutions revealed that the isomerization barriers (ΔG≠ at 350 K) are 26.4 and 27.2 kcal mol−1 for 7 and 8, respectively. Isomerization pathways were investigated by molecular mechanics calculations, which suggested that gear rotational pathway was favored. In either compound, the sc* (9S*) rotamer was found to thermally isomerize to the ap rotamer in the solid state. X-Ray crystallographic analysis of the rotameric crystals showed that the rotamers had different crystal structures and thus the crystal would be destroyed during the isomerization.
Rotational Isomerism and Atropisomerism in Acetal Derivatives of 1,2,3,4-Tetrafluorotriptycene-9-carbaldehyde
Authors: Yamamoto Gaku 
Published: July 2006

Abstract
In the ethylene acetal (2) of 1,2,3,4-tetrafluorotriptycene-9-carbaldehyde, equal amounts of the ap and ±sc rotamers exist in CDCl3 at equilibrium, while the equilibrium is strongly shifted to ±sc in the corresponding dimethyl and trimethylene acetals. Molecular mechanics calculations reveal the origin of this anomaly to reside in the conformation of the acetal moiety. Dynamic NMR studies show that the ap → ±sc barriers are too low for atropisomerism to be realized in these compounds (ΔG≠ ca. 21–22 kcal mol−1 (1 calth = 4.184 J)). However, taking advantage of the unusual equilibrium behavior, the two rotamers of 2 are separately isolated as crystals by selective crystallization of one rotamer from a solution of the equilibrated rotamer mixture.