Thermal base

Less common synthetic methods for 1,3,4-thiadiazoles include the oxidative thermal base-catalyzed cyclization of thiosemicarbazido arylates (Equation 40) <2005HAC12> and a tetracyanoethylene (TCNE)-assisted cyclization (Equation 41) <2004ZNB910>. 

The regiospecific nucleophilic displacement of 1,2-cyclic sulfamidates 130 with methyl thioglycolate or a-amino esters 130 can be accompanied by lactamization (thermal, base mediated, or cyanide catalyzed) to give thiomorpho-lin-3-ones and piperazin-2-ones 131 (Scheme 19) <20030L811>. If malonate esters, phosphonate-stabilized esters, or aryl-substituted enolates were used as nucleophiles in this reaction, trisubstituted pyrrolidines were obtained in high yield <2004OL4727>. 

Cyclic nitrones 1490 (A -imidazoline 3-oxides) react regioselectively with alkyl phenylpropiolates 1491 (or with dimethyl acetylenedicarboxylate) to give the corresponding 2-phenyl-3a,4,5,6-tetrahydroimidazo[l,5- ]isoxazole-3-carboxylic acid alkyl esters 1492. Subsequent thermal, base (piperidine, triethylamine, or alkoxide) induced ringopening reactions led to imidazoles 1493 (Scheme 385) <2004SC1617, 2000TL5407>. 

Anibine (108) was synthesized in three steps from a masked acyl anion equivalent, a-(3-pyridyl)-a-(4-morpholino)acetonitrile, and ethyl ( )-4-bromo-3-methoxy-2-butenoate. Acid hydrolysis of the product from this reaction, followed by a thermal, base promoted cyclization gave 108 [307],... 

Calibration is one of the important issues for quantitative determination of the shear stress vector from measurement. The suitability of the shear stress sensor for a particular application is based on the complexity of the calibratirm procedure. The calibration of thermal-based shear stress sensors and the calibration setup required is described below. Similar setup can be used for calibration of other types of shear stress sensors. The calibration process is categorized as static and dynamic. 

Baltes H, Paul O, Brand O (1998) Micromachined thermally based CMOS microsensors. Proc IEEE 86(8) 1660-1678... 

Lalinsky T, Drzflc M, Iakovenko J, Husak M (2005) GaAs thermally based MEMS devices fabrication techniques, characterization and modeling. In Leondes CT (ed) MEMS/NEMS handbook techniques and applications, vol 3. Springer, New York... 

PVDF exhibits pyroelectric as well as piezoelectric properties [44], a feature that has made the material useful for infrared sensing in motion detectors and thermal cameras. This attribute has been used recently in a thermally based method to measure ultrasonic power [45]. A 52 pm thick film of PVDF 60 mm in diameter was used as the sensor, which was backed with a rubber based material that generated heat due to ultrasonic absorption. Powers up to 1 W over a frequency range of 1-3.5 MHz were measured in this preliminary study. 

This book reviews the various thermally based methods for the characterisation of polymer properties and composition. 

Other thermally based techniques, which have been developed in recent years include thermal volatilisation (Chapter 5), dynamic mechanical analysis (Chapter 8), thermomechanical analysis (Chapter 9), microthermal analysis (Chapter 10) and dielectric thermal analysis (Chapter 12). These have been used in phase transition studies, resin cure, modulus measurement, stress-strain studies, viscoelastic and rheological properties, morphology, topography, mechanical and thermal properties. 

It is worth indicating that the equivalent temperatures obtained in all the cases were consistent and significantly higher than the maximum temperature measured in the samples, providing further support that the microwave curing is not merely thermal based. ... 

Anomalous glasses are more difficult to score. In feet, glass densification underneath the scoring wheel blunts the median crack propagation (see Section 8.1.3.4). More acute scoring wheeb are recommended. Moreover, those glasses abo present better thermal shock resistance (Chapter 2). Hence, thermal based methods for breakage cannot be used. 

It should be emph ized that although other thermal-based remediation mediods, such as steam injection, offer some advwitages as electrical heating, they suffer from the same difficulties as P T when low permeability soil is present as the non-uniform flow paths limit the pafliways of die steam (11,12). Elecfrical heating, however, is not limited by the presence of low permeability... 

Reactivity coefficients. By means of a series of calculations in which the thermal base, the core radius, and the density of the fuel salt are varied independently, the components of the temperature coefficient of reactivity of a reactor can be estimated as illustrated below for a core 8 ft in diameter and a thorium concentration of 0.75 mole % in the fuel salt at 1150 F. From the expression... 

Clusiacyclol A 171 and B 172 were isolated from the fruit extract of Clusia multiflora in 1994 by Monache and coworkers [90]. The compounds with oxacyclobutaindan core units have been synthesized previously by using intramolecular [2-1-2] photochemical [73,77,91] or acid-catalyzed cationic [75] cycloaddition reactions of various suitably substituted benzopyrans. Argade and coworkers have demonstrated a simple and efficient phenol-directed intramolecular diastereoselective dipolar thermal/base-catalyzed [2-1-2] cycloaddition approach to novel biologically important natural and synthetic benzopyran systems (Scheme 12.41) [92]. The trihydroxybenzophenone 167 was synthesized with high yield from trimethoxybenzene 166 via... 

Friedel-Crafts benzoylation, followed by demethylation. Ca(OH)2/DBU promoted the formal [3+3] cycloaddition of benzophenone 167 with citral to furnish the mixture of products 169+172 (inseparable), 170+171 (inseparable), and a diastereomeric mixture of 168 (inseparable). However, when using less equivalents of DBU, this reaction can obtain the column separable mixture of 168+169+170 or using an excess amount of Ca(OH)2, the separable mixture of 168+171+172 was formed. The ( )-clusiachromene C 169 Clusia multiflora) on thermal/base-catalyzed [2+2] cycloaddition gave the desired natural product ( )-clusiacy-clol B 172 in very good yield. Similarly, the natural product ( )-clusiacyclol A 171 was obtained by thermal/base-catalyzed [2+2] cycloaddition of 170 [92]. 

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