Saccharin and derivatives

Heat 0 5 g. of pseudo-saccharin chloride with an excess of the phenol to 125-140° for 15-20 minutes hydrogen chloride is evolved. Wash the product with dilute sodium hydroxide solution and then with water. Recrystallise the derivative from ethanol.  [c.684]

Deposition from Liquid Gold. Liquid gold refers either to organic suspensions or emulsions containing finely divided gold powder or to solutions of organogold compounds in organic solvents. Liquid golds are formulated as paints or inks which are appHed by painting, bmshing, screen printing, etc, and that yield weU-bonded gold films after subsequent drying and firing. The thickness of films derived from dispersed metal is ca 25 p.m. The thickness of films derived from organogold compounds ranges from (5-20) x 10 //m.  [c.385]

Substance information in the Registry file may be searched in a variety of ways, eg, stmcture information may be searched using stmctures buHt on-line with the Stmcture command or with codes (screen numbers) for predefined stmctural fragments or class identifiers. Another option is to upload stmctures drawn using STN Express or other stmctiire-huilding software, eg, ChemDraw. Protein and nucleic acid sequences may be searched using codes for amino acids or nucleotides. Substance names may be searched using complete names or name fragments. Complete molecular formulas, molecular formula fragments, and information derived from these formulas, including element counts, atom counts, formula weights, and element symbols, may be used to retrieve compounds from the file. Ring identifiers and ring analysis terms may be used to retrieve substances containing ring systems. Polymers may be retrieved using polymer class terms. AHoys may be retrieved using weight percentages and relative compositions.  [c.117]

Screen Process Inks. These inks, often known in the past as silk-screen inks, are printed on the substrate by being forced through a screen stencil by means of a squeegee. For many years this was a band-printing operation, but it has now become largely mechanized. Screen-process inks are dispersions of pigments ia vehicles which are, for the most part, solutions of resias ia solvents of the boiling range of VM P naphtha. Drying of solvent-based inks is usually by evaporation, but ia some cases it is a combination of oxidation and evaporation. Various types of biaders are used such as rosia esters, phenoHcs, cellulose derivatives, vinyls, and oleoresiaous varnishes, depending on the film properties desired. Uv inks are also widely used for screen-process printing. After premixing, the ink is ground on a three-roll or media mill. The resulting ink should be short and soft so as not to drag on the squeegee and to release the substrate cleanly after the print is made.  [c.253]

Development of Drugs. The vast majority of dmgs available were derived from large-scale screenings. In many cases Httle is known about the target protein or other macromolecule, or the mode of action. The type of molecule for use as a dmg is inferred from the biochemical mechanism of a disease. This information is then used to screen databanks containing thousands of compounds. Modifications to the leading candidates are then made and tested further for efficacy. It can take from 6 to 12 years for a dmg to come to the market (31) (see Antibiotics Antiparasitic agents).  [c.215]

Fiber Felts. Fiber glass felts are manufactured from glass filaments prepared from a molten mixture of siUca sodium carbonate, recycled glass, sand, and other ingredients. The filaments may be short (chopped) or continuous. They may be deposited dry or from a dilute water slurry on a screen conveyor. In either process, a binder is appHed. Heat is then appHed to set the binder. The formed fiber glass mat is then coated with hot asphalt, surfaced with a parting agent (Uquid or mineral), cooled, marked with guidelines, and wound into roUs of the desired length. Excellent dimensional stabiUty and low moisture absorption are derived from fiber glass roofing felts. For the production of rnineral-surfaced roofing products or shingles, mineral granules are appHed to a heavier-coated top side of the felt. Variations in the manufacturing process also produce venting base sheets and flashings. Fiber glass mats are also used to produce modified bitumen roofing products.  [c.212]

With the advent of the wire belted radial tire, irregular tread wear became a significantly greater problem. The mechanical working of the tread elements through the rolling contact area are much more sensitive to the design and precision of the tire components as well as the wheel alignments of the vehicle. These latter mechanical entities are primary in the occurrence of irregular wear. However, the compound can help. Tread compounds with high elastic modulus at 50—75°C have been found to be less sensitive in that they increase stiffness and reduce tread element squirm or sHp through the contact area. Many different conditions and correlative formulas have been derived to predict tire performance parameters from laboratory physical properties.  [c.252]

Both Watts and sulfamate baths are used for engineering appHcation. The principal difference in the deposits is in the much lower internal stress obtained, without additives, from the sulfamate solution. Tensile stress can be reduced through zero to a high compressive stress with the addition of proprietary sulfur-bearing organic chemicals which may also contain saccharin or the sodium salt of naphthalene-1,3,6-trisulfonic acid. These materials can be very effective in small amounts, and difficult to remove if overadded, eg, about 100 mg/L of saccharin reduced stress of a Watts bath from 240 MPa (34,800 psi) tensile to about 10 MPa (1450 psi) compressive. Internal stress value vary with many factors (22,71) and numbers should only be compared when derived under the same conditions.  [c.161]

Another approach to the design phase of the structure-based design cycle utilizes the computet program DOCK, which iacreases the chances that compounds chosen for testing will be inhibitors. Novel lead compounds have been developed for l ctobacillus casei thymidylate synthase by usiag DOCK, x-ray crystallography, and additional computational analysis for the selection of potential inhibitors from a pool of commercially available compounds (61). Initial, weak-binding inhibitors were found by using DOCK and the x-ray crystal stmcture of TS to screen the small molecule database, FCD. X-ray crystal stmctures of resulting enzyme-inhibitor complexes were further analyzed, generating a pool of potential inhibitors. DOCK was then used to assess the complementarity of these molecules to the enzyme active site, and they were rank-ordered accordingly. As can be seen in Table 2, many of the top-scoring compounds showed inhibition in the ]lM range. The stmctures of the top tanked compounds with IC qS at or below 100 ]lM are shown in Figure 9. These phenolphthalein derivatives are quite different in stmcture from the natural substrates of TS, which is useful for novel lead discovery.  [c.327]

Benzisothiazole 1,1-dioxides and saccharin derivatives are best prepared by cyclization of o-substituted benzenesulfonamides (see Section  [c.173]

The next article is by Raymond Andersen and David Williams of the Departments of Chemistry and of Earth and Ocean Sciences at the University of British Columbia. This is concerned with the opportunities and challenges involved in developing new pharmaceuticals from the sea. Historically, drug discovery programmes have relied on in vitro intact-tissue or cell-based assays to screen libraries of synthetic compounds or natural product extracts for pharmaceutically relevant properties. However, modem high-throughput screening methods have vastly increased the numbers of assays that can be performed, such that libraries of up to 100000 or more chemical entities can now be screened for activity in a reasonable time frame. This has opened the way to exploitation of natural products from the oceans in this context. Many of these marine natural products have no terrestrial counterparts and offer unique opportunities for drug applications. Examples of successful marine-derived drugs are given and the potential for obtaining many more new pharmaceuticals from the sea is clearly demonstrated.  [c.103]

Saccharin was discovered at Johns Hopkins University in 1879 in the course of research on coal-tar derivatives and is the oldest artificial sweetener. In spite of its name, which comes from the Latin word for sugar, saccharin bears no structural relationship to any sugar. Nor is saccharin itself very soluble in water. The proton bonded to nitrogen, however, is fairly acidic and saccharin is normally marketed as its water-soluble sodium or calcium salt. Its earliest applications were not in weight control, but as a  [c.1051]

The accuracy of the device is limited by the linearity of the circuit which moves the beam horizontally in response to time (i.e. the time base ) and the response of the input circuit. The time base is generated by a sweep circuit which is triggered to instigate the start of the movement. The triggering signal may be derived from the voltage that is being measured or it may be obtained from an entirely separate source. This can cause difficulties in some applications. If it is required to examine a voltage pulse then the simplistic approach is to allow the pulse itself to trigger the signal. This is unsatisfactory, if it is the leading edge of the pulse which is of interest, and therefore a delay is built into the instrument which allows the trace to be triggered immediately the pulse is applied but which delays the application of the signal to the vertical deflection plates for a short time in order to enable the pulse to be displayed in the middle of the screen.  [c.241]

Low frequency (up to around 30 MHz) typical deflection sensitivities are between 0.1 mV/cm and 10 V/cm. This is a general-purpose instrument and can incorporate a second trace energized by a voltage different from the first and using the same or different deflection speeds for the time base. An alternative is to use a single beam but to apply a chopped signal to the deflection plates. Sampling the two separate signals for brief intervals of time and applying each in turn to the plates derives the applied signal. The luminescent persistence of the screen then results in two continuous traces (one corresponding to each of the two applied voltages) to be observed.  [c.241]

The Latin word for sugar is saccharum and the derived term saccharide is the basis of a system of carbohydrate classification A monosaccharide is a simple carbohydrate one that on attempted hydrolysis is not cleaved to smaller carbohydrates Glucose (C6H12O6)  [c.1026]

Many commercially available software packages, such as AutoCAD and VersaCAD, can be used to draw chemical processes ia block-diagram representation. Eigure 1 illustrates typical screen displays of some ia-house programs. To manipulate block diagrams, numerous automated procedures are also available. Various poiater devices (mouse, light pen, joystick, and others) are used for iateractive selection of particular blocks or branches for simplification and derivation of the system s transfer function. The fundamental steps that need to be taken ia such manipulations, usiag a program called  [c.62]

Benzisothiazoles suffer straightforward ring cleavage, but their 1,1-dioxides, 2,1-benzisothiazoles and derivatives of saccharin give products containing no sulfur.  [c.146]

The Latin word for sugar is saccharum, and the derived tenn saccharide is the basis of a system of caibohydrate classification. A monosaccharide is a simple caibohydrate, one that on attempted hydrolysis is not cleaved to smaller caibohydrates. Glucose  [c.1026]

Maggini M, Done A, Scorrano G and Prato M 1995 Synthesis of a [60]fullerene derivative covalently linked to a ruthenium (II) tris(bipyridine) complex J. Chem. Soc., Chem. Commun. 845-6  [c.2436]

For this purpose the 1,3-butadiene, ethane, and eydohexene are drawn as separate fragments on the same screen of the struemre editor. Since the bonds in open-chain fragments arc set by default to ring or chain", the user has to adjust the attributes of the bonds. After clicking the bond with the pencil tool, a new window with the bond attributes is opened where users can select the desired topology in the drop-down menu (Figure 5-20). Since numerous derivatives are involved in Dicls-Aldcr reactions, all atoms arc allowed to be substituted after selecting all fragments and choosing the option Set Free Sites" in the Queiy menu of the structure editor (see also Figure 5-16).  [c.254]

Researchers from Ho fmann-La Roche discovered new inhibitors of DNA gyiase by combining several key techniques [90], On the basis of the 3D structural information of the binding site they started with an in silico screening for potential low molecular weight inhibitors followed by a biased high-throughput DNA gyrase screen. The hits of the screening were validated by biophysical methods and finally optimized in a 3D guided optimization process. The lead optimization of an inda-zole derivative resulted in a DNA gyrase inhibitor that was 10 times more potent than novobiocin.  [c.616]

Saccharin was discovered at Johns Hopkins Uni versity in 1879 in the course of research on coal tar derivatives and is the oldest artificial sweetener In spite of Its name which comes from the Latin word for sugar saccharin bears no structural relationship to any sugar Nor is saccharin itself very soluble in wa ter The proton bonded to nitrogen however is fairly acidic and saccharin is normally marketed as its water soluble sodium or calcium salt Its earliest applications were not in weight control but as a  [c.1051]

Cake flours are milled from low protein soft wheat especially suitable for baking cakes and pastries or from low-protein fractions derived in the milling process. Cake flours are usually not enriched, but are bleached. The sale of cake flours declined during the 1950s as packaged cake mixes became more popular. Instantised, instant blending, or quick-mixing flour is a granular or more dispersible type of product for home use. It is free-pouring like salt, and dust-free compared to regular flour. It eliminates the need for sifting, since it does not pack down in the package and since it pours right through a screen or sieve. Granular flour instantly disperses in cold Hquid rather than hailing or lumping as does regular flour. The granular flour is produced by special processes of grinding and bolting, or from regular flour subjected to a controlled amount of finely dispersed moisture that causes the flour to clump or agglomerate. It is then dried to a normal moisture level (47,48). Gluten flour is milled to have a high wheat gluten and a low starch content and is used primarily by bakers for dietetic breads, or mixing with other flours of a lower protein content.  [c.358]

Paper consists of sheet materials that are comprised of bonded small discrete fibers. The fibers usually are ceUulosic in nature and are held together by hydrogen bonds (see Cellulose). The fibers are formed into a sheet on a fine screen from a dilute water suspension. The word paper is derived from papyms, a sheet made in ancient times by pressing together very thin strips of an Egyptian reed Cjperuspapyrus) (1).  [c.1]

Derivatives. The remaining uses are better considered as derivatives of phthahc anhydride and consume less than 10% of the demand, but they provide a diverse group of products. Anthraquinone (qv), a starting reagent for a number of dye intermediates, is manufactured by heating phthahc acid and benzene with sulfuric acid as a catalyst. Use of chlorobenzene instead of benzene results in 2-chloroanthraquinone, a dye. Examples of dyes derived from phthahc anhydride are phthalocyanine blues, quinoline yellow, and anthracene brown (see Dyes and dye intermediates). Another use for phthahc anhydride is in the production of isatoic anhydride [118-48-9] a raw material used in the production of saccharin. Tetrachloro- and tetrabromophthahc anhydrides are manufactured by the reaction of phthahc anhydride with chlorine and bromine, respectively, at high temperatures. The halogenated forms impart fire resistance to polyester resins, polyurethane foams, and surface coatings. Phenolphthalein [77-09-8] is the condensation product of phthahc anhydride and phenol in the presence of a dehydrating agent, and is a pH indicator and laxative. Pesticides and anthranilic acid [118-92-3] can be made from phthahmide which is in turn produced from phthahc anhydride.  [c.485]

The dimensions of the heterocyclic ring of some typical crystalline derivatives of isothiazole, 1,2- and 2,1-benzisothiazole are listed in Table 3. Bond lengths should be compared with those of single and double bonds given at the foot of the table. All the molecules are more or less planar except (12), where the bulky 3-substituent causes twisting. The S—N bonds are significantly shorter than the single bond values, confirming the MO predictions of rr-electron delocalization. In addition, the short N—C bonds in the 1,2-benzisothiazol-3-ones (10) and C—S and S—N bonds in saccharin (7) confirm that ir-delocalization occurs in these molecules. In the case of saccharin (which is planar apart from the S=0 bonds) this delocalization must involve the empty sulfur 3d-orbitals. The benzene ring of saccharin is significantly distorted so that the angles at positions 4 and 7 are reduced to 117.7° and 116.0°, respectively, suggesting an o-quinonoid contribution to the structure. The very short S—N bond of (12) can be accounted for if resonance forms such as (13) are taken into account. In the case of 5-chloro-2,l-benzisothiazole the bond lengths and planarity of the molecule show the effect of resonance of the type exemplified in (7) on the ground state of the molecule.  [c.134]

The isothiazole ring does not occur in nature. By far the most important synthetic isothiazole derivative is saccharin. This was the first non-carbohydrate sweetening agent to be discovered, as long ago as 1879. It is about 300 times as sweet as sucrose, and is still used in many countries as a non-nutritive sweetener. After it was found that administration of massive doses to rats caused bladder cancer, its use was banned in the New World, but the controversy continues as to whether there is any danger when it is used in small quantity. Saccharin is also used as an additive in electroplating processes (73AHC(15)233).  [c.173]

Bentonite has expected sihca content of 0.5 weight percent (F is 0.005). Silica density (A ) is 2.4 gm per cii cm, and bentonite (Ag) is 2.6. The calculation requires knowledge of mineral properties described by the factor (fghd ). Value of the factor can be estabhshed from fundamental data (Gy) or be derived from previous experience. In this example, data from testing a shipment of bentonite of 10 mesh top-size screen analysis determined value of the mineral factor to be 0.28. This value is scaled by the cube of diameter to ys-in screen size of the example shipment. The mineral factor is scaled from 0.28 to 52 by multiplying 0.28 with the ratio of cubed 9.4 mm (ys-in screen top-size of the shipment to be tested) and cubed 1.65 mm (equivalent to 10 mesh).  [c.1757]

The recovered, hydrogenated coal products, prepared under identical conditions, were combmed and ground to pass through a course-mesh screen (Tyler 8 mesh) in a glove box to reduce oxidation. The ground product was evenly distributed in a rectangular stainless steel pan and the contents of the pan divided mto six equal quadrants. Material from each quadrant was sampled representatively and then sealed under nitrogen in plastic bags. Finally, the coal-derived pitch was stored at reduced temperature until ready for use. It was thought that the sampling and storage procedure described above would ensure coke and graphite production feedstock of a relatively uniform and homogeneous nature. The solvent extracted material from the hydrogenated coal will be subsequently referred to as HEXT with the hydrogenation temperature as a suffix.  [c.215]

In an extension of this work Scheeren et al. studied a series of derivatives of N-to-syl-oxazaborolidinones as catalysts for the 1,3-dipolar cycloaddition reaction of 1 with 2b [29]. The addition of a co-solvent appeared to be of major importance. Catalyst 3b was synthesized from the corresponding amino acid and BH3-THF, hence, THF was present as a co-solvent. In this reaction (-)-4b was obtained with 62% ee. If the catalyst instead was synthesized from the amino acid and  [c.218]

See pages that mention the term Saccharin and derivatives : [c.151]    [c.480]    [c.545]    [c.145]    [c.159]    [c.160]    [c.164]    [c.167]    [c.167]    [c.168]    [c.171]    [c.175]    [c.138]    [c.73]    [c.218]   
Advances in heterocyclic chemistry Vol.80 (2001) -- [ c.15 , c.233 ]

Advances in heterocyclic chemistry Vol.85 (2003) -- [ c.15 , c.233 ]