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Introduction:The perception of flavor is a complicated physiological andpsychological response that incorporates the sight, smell, taste,and texture of an object. A large portion of the perceived flavor ofa food actually comes from its fragrance. Remember your lastcold? How did things taste? Many foods, including spearmint gumand onions, do not have a taste at all if your sense of smell isimpaired.The major components of most flavors and fragrances are a class ofcompounds known as esters. Esters are derived from the reactionof carboxylic acids and alcohols. Most aromas are not singlecompounds, but complex mixtures. For example, over 200 estershave been identified in the rich aroma of coffee. However, severalcommon fragrances have a major ester component.
also known as odorant, aroma, fragrance or flavor, is a chemical compound that has a smell or odor. A chemical compound has a smell or odor when two conditions are met: the compound needs to be volatile, so it can be transported to the olfactory system in the upper part of the nose, and it needs to be in a sufficiently high concentration to be able to interact with one or more of theolfactory receptors. Aroma compounds can be found in food, wine, spices, perfumes, fragrance oils, and essential oils. For example, many form biochemicallyduring ripening of fruits and other crops. In wines, most form as byproducts of fermentation. Odorants can also be added to a dangerous odorless substance, like propane, natural gas, or hydrogen, as a warning. Also, many of the aroma compounds play a significant role in the production of flavorants, which are used in the food service industry to flavor, improve, and generally increase the appeal of their products.
The manufacture of (-)-menthol from (+)-pulegone (ex Spanish pennyroyal oil) similarly is dependent on configuration at C-1 in the present material.14 In this process the 4,8-double bond is catalytically hydrogenated and then the mixture of (-)-menthone and (+)isomenthone so produced is reduced by sodium in alcohol to give predominantly (-)-menthol. Reduction of menthones by nascent hydrogen generated in situ is the preferred procedure inasmuch as this system allows epimerization of the isopropyl group and preferential reduction to an all-equatorial substituent system, presumably via the enolate.1 References1. Leffingwell, J.C. & R.E. Shackelford, Laevo-Menthol - Syntheses and organoleptic properties, Cosmetics and Perfumery, 89(6), 69-89, 1974 2. Hopp, R., Menthol: its origins, chemistry, physiology and toxicological properties, Rec. Adv. Tobacco Science, Vol. 19, 3- 46 (1993).
(-)-Menthol from Geraniol or Nerol or Geranial or NeralA New BASF Process
utilizes (+)-(R)- citronellal which can be produced from either geraniol or nerol by chiral catalytic hydrogenation to (+)-(R)-citronellol (Ref. 2) (in a manner similar to that described in 1987 by Ryoji Noyori and co-workers [Ref. 3]) followed by catalytic dehydrogenation to (+)-(R)- citronellal. In addition, BASF has also achieved the direct chiral catalytic hydrogenation of neral or geranial to (+)-(R)-citronellal (Ref. 4). This latter route as depicted in Scheme 2 appears to be the commercial route.
has recently developed refined processes for the cyclization of (+)-(R)-citronellal to (-)- Isopulegol that minimizes the undesirable isomeric isopulegols (Ref. 5); further they have developed an improved process for enriching the (-)-Isopulegol before the hydrogenation step to (-)-menthol (Ref. 6). A continuous distillation process for purifying the final menthol product has also been achieved (Ref. 7).
Nissen, Axel; Rebafka, Walter; Aquila, Werner, Preparation of citral, United States Patent 4288636 (09/08/1981); Therre, Jorg; Kaibel, Gerd; Aquila, Werner; Wegner, Gunter; Fuchs, Hartwig, Preparation of citral, United States Patent 6175044 (01/16/2001); Dudeck, Christian; Diehm, Hans; Brunnmueller, Fritz; Meissner, Bernd; Fliege, Werner; Preparation of 3-alkyl-buten-1-als, United States Patent 4165342 (08/21/1979); W.F. Hoelderich & F. KolLmer, Chapter 2 in Catalysis, Volume 16, James J. Spivey, Ed., Royal Society of Chemistry, 2002. pp. 45-46 2. Bergner, Eike Johannes; Ebel, Klaus; Johann, Thorsten; Lober, Oliver, Method for the production of menthol, United States Patent 7709688 (05/04/2010); Johann, Thorsten; Löber, Oliver; Bergner, Eike Johannes; Ebel, Klaus; Harth, Klaus; Walsdorff, Christian; Method for producing optically active carbonyl compounds, United States Patent 7468463 (12/23/2008) 3. Hidemasa Takaya, Tetsuo Ohta, Noboru Sayo, Hidenori Kumobayashi, Susumu Akutagawa, Shinichi Inoue, Isamu Kasahara, Ryoji Noyori, Enantioselective hydrogenation of allylic and homoallylic alcohols, J. Am. Chem. Soc., 1987, 109 (5), pp 1596–1597 4. Jäkel, Christoph; Paciello, Rocco; Method for the production of optically active carbonyl, United States Patent 7534921 (05/19/2009) 5. Friedrich, Marko; Ebel, Klaus; Götz, Norbert; Method for the production of isopulegol, United States Patent 7550633 (06/23/2009); Friedrich, Marko; Ebel, Klaus; Götz, Norbert; Krause, Wolfgang; , Zahm, Christian; Diarylphenoxy aluminum compounds,United States Patent 7608742 (10/27/2009) 6. Rauls, Matthias; Jakel, Christoph; Kashani-shirazi, Nawid; Ebel, Klaus, Method for the Production of Enriched Isopulegol, United States Patent Application 20080214877 (09/04/2008) 7. Heydrich, Gunnar; Gralla, Gabriele; Ebel, Klaus; Krause, Wolfgang; Kashani-shirazi, Nawid,CONTINUOUS PROCESS FOR PREPARING MENTHOL IN PURE OR ENRICHED FORM, WIPO Patent Application WO/2009/033870 (03/19/2009) Please note that the above references encompass only a small number of the numerous BASF patents & patent applications relative to menthol synthesis. 8. John C. & Diane Leffingwell, Chiral chemistry in flavours & fragrances, Speciality Chemicals Magazine, March 2011, pp. 30-33
Vanillin IUPAC name 4-Hydroxy-3-methoxybenzaldehyde
is a phenolic aldehyde, an organic compound with the molecular formula C8H8O3. Itsfunctional groups include aldehyde, ether, and phenol. It is the primary component of the extract of the vanilla bean. Synthetic vanillin, instead of natural vanilla extract, is sometimes used as aflavoring agent in foods, beverages, and pharmaceuticals. Vanillin as well as ethylvanillin is used by the food industry. The ethyl is more expensive but has a stronger note. It differs from vanillin by having an ethoxy group (–O–CH2CH3) instead of a methoxy group (–O–CH3). Natural "vanilla extract" is a mixture of several hundred different compounds in addition to vanillin. Artificial vanilla flavoring is a solution of pure vanillin, usually of synthetic origin. Because of the scarcity and expense of natural vanilla extract, there has long been interest in the synthetic preparation of its predominant component. The first commercial synthesis of vanillin began with the more readily available natural compound eugenol. Today, artificial vanillin is made either from guaiacol or from lignin, a constituent of wood, which is a byproduct of the pulp industry. Lignin-based artificial vanilla flavoring is alleged to have a richer flavor profile than oil-based flavoring; the difference is due to the presence of acetovanillone in the lignin-derived product, an impurity not found in vanillin synthesized from guaiacol.
Vanilla was cultivated as a flavoring by pre-Columbian Mesoamerican peoples; at the time of their conquest by Hernán Cortés, the Aztecs used it as a flavoring for chocolate. Europeans became aware of both chocolate and vanilla around 1520. Vanillin was first isolated as a relatively pure substance in 1858 by Nicolas-Theodore Gobley, who obtained it by evaporating a vanilla extract to dryness, and recrystallizing the resulting solids from hot water. In 1874, the German scientists Ferdinand Tiemann and Wilhelm Haarmann deduced its chemical structure, at the same time finding a synthesis for vanillin fromconiferin, a glycoside of isoeugenol found in pine bark. Tiemann and Haarmann founded a company, Haarmann & Reimer (now part of Symrise) and started the first industrial production of Vanillin using their process in Holzminden (Germany). In 1876, Karl Reimer synthesized vanillin (2) from guaiacol (1). Synthesis of Vanillin by Reimer By the late 19th century, semisynthetic vanillin derived from the eugenol found in clove oil was commercially available.
Natural vanillin is extracted from the seed pods of Vanilla planifola, a vining orchid native to Mexico, but now grown in tropical areas around the globe. Madagascar is presently the largest producer of natural vanillin. As harvested, the green seed pods contain vanillin in the form of its β-D-glycoside; the green pods do not have the flavor or odor of vanilla. β-D-glycoside of vanillin After being harvested, their flavor is developed by a months-long curing process, the details of which vary among vanilla-producing regions, but in broad terms it proceeds as follows: First, the seed pods are blanched in hot water, to arrest the processes of the living plant tissues. Then, for 1–2 weeks, the pods are alternately sunned and sweated: during the day, they are laid out in the sun, and each night, wrapped in cloth and packed in airtight boxes to sweat. During this process, the pods become a dark brown, and enzymes in the pod release vanillin as the free molecule. Finally, the pods are dried and further aged for several months, during which time their flavors further develop. Several methods have been described for curing vanilla in days rather than months, although they have not been widely developed in the natural vanilla industry, with its focus on producing a premium product by established methods, rather than on innovations that might alter the products flavor profile. Vanillin accounts for about 2% of the dry weight of cured vanilla beans, and is the chief among about 200 other flavor compounds found in vanilla.
The demand for vanilla flavoring has long exceeded the supply of vanilla beans. As of 2001, the annual demand for vanillin was 12,000 tons, but only 1,800 tons of natural vanillin were produced. The remainder was produced by chemical synthesis. Vanillin was first synthesized from eugenol (found in oil of clove) in 1874–75, less than 20 years after it was first identified and isolated. Vanillin was commercially produced from eugenol until the 1920s. Later it was synthesized from lignin-containing "brown liquor", a byproduct of the sulfite process for makingwood pulp. Counter-intuitively, even though it uses waste materials, the lignin process is no longer popular because of environmental concerns, and today most vanillin is produced from the petrochemical raw material guaiacol. Several routes exist for synthesizing vanillin from guaiacol. At present, the most significant of these is the two-step process practiced by Rhodia since the 1970s, in which guaiacol (1) reacts withglyoxylic acid by electrophilic aromatic substitution. The resulting vanillylmandelic acid (2) is then converted via 4-Hydroxy-3-methoxyphenylglyoxylic acid (3) to vanillin (4) by oxidative decarboxylation. In October 2007 Mayu Yamamoto of the International Medical Center of Japan won an Ig Nobel Prize for developing a way to extract vanillin from cow dung.
References Adahchour, Mohamed; René J. J. Vreuls, Arnold van der Heijden and Udo A. Th. Brinkman (1999). "Trace-level determination of polar flavour compounds in butter by solid-phase extraction and gas chromatography–mass spectrometry". Journal of Chromatography A844 (1–2): 295–305. doi:10.1016/S0021-9673(99)00351-9.PMID 10399332. Blank, Imre; Alina Sen, and Werner Grosch (1992). "Potent odorants of the roasted powder and brew of Arabica coffee". Zeitschrift für Lebensmittel-Untersuchung und -Forschung A 195 (3): 239–245.doi:10.1007/BF01202802. Brenes, Manuel; Aranzazu García, Pedro García, José J. Rios, and Antonio Garrido (1999). "Phenolic Compounds in Spanish Olive Oils".Journal of Agricultural and Food Chemistry 47 (9): 3535–3540.doi:10.1021/jf990009o. PMID 10552681. Buttery, Ron G.; and Louisa C. Ling (1995). "Volatile Flavor Components of Corn Tortillas and Related Products". Journal of Agricultural and Food Chemistry 43 (7): 1878–1882.doi:10.1021/jf00055a023. Dignum, Mark J. W.; Josef Kerlera, and Rob Verpoorte (2001). "Vanilla Production: Technological, Chemical, and Biosynthetic Aspects".Food Reviews International 17 (2): 119–120. doi:10.1081/FRI-100000269. Retrieved 2006-09-09. Esposito, Lawrence J.; K. Formanek, G. Kientz, F. Mauger, V. Maureaux, G. Robert, and F. Truchet (1997). "Vanillin". Kirk- Othmer Encyclopedia of Chemical Technology, 4th edition. 24. New York: John Wiley & Sons. pp. 812–825. Fund for Research into Industrial Development, Growth and Equity (FRIDGE) (2004). Study into the Establishment of an Aroma and Fragrance Fine Chemicals Value Chain in South Africa, Part Three: Aroma Chemicals Derived from Petrochemical Feedstocks. National Economic Development and Labor Council. Gobley, N.-T. (1858). "Recherches sur le principe odorant de la vanille". Journal de Pharmacie et de Chimie 34: 401–405. Guth, Helmut; and Werner Grosch (1995). "Odorants of extrusion products of oat meal: Changes during storage". Zeitschrift für Lebensmittel-Untersuchung und -Forschung A 196 (1): 22–28.doi:10.1007/BF01192979. Hocking, Martin B. (September 1997). "Vanillin: Synthetic Flavoring from Spent Sulfite Liquor" (PDF). Journal of Chemical Education 74(9): 1055–1059. doi:10.1021/ed074p1055. Retrieved 2006-09-09. Kermasha, S.; M. Goetghebeur, and J. Dumont (1995). "Determination of Phenolic Compound Profiles in Maple Products by High-Performance Liquid Chromatography". Journal of Agricultural and Food Chemistry 43 (3): 708– 716. doi:10.1021/jf00051a028. Lampman, Gary M.; Jennifer Andrews, Wayne Bratz, Otto Hanssen, Kenneth Kelley, Dana Perry, and Anthony Ridgeway (1977). "Preparation of vanillin from eugenol and sawdust". Journal of Chemical Education 54 (12): 776– 778. doi:10.1021/ed054p776. Ong, Peter K. C.; Terry E. Acree (1998). "Gas Chromatography/Olfactory Analysis of Lychee (Litchi chinesis Sonn.)".Journal of Agricultural and Food Chemistry 46 (6): 2282–2286.doi:10.1021/jf9801318. Reimer, K. (1876). "Ueber eine neue Bildungsweise aromatischer Aldehyde". Berichte der deutschen chemischen Gesellschaft 9 (1): 423–424. doi:10.1002/cber.187600901134. Roberts, Deborah D.; Terry E. Acree (1996). "Effects of Heating and Cream Addition on Fresh Raspberry Aroma Using a Retronasal Aroma Simulator and Gas Chromatography Olfactometry". Journal of Agricultural and Food Chemistry 44 (12): 3919–3925.doi:10.1021/jf950701t. Rouhi, A. Maureen (2003). "Fine Chemicals Firms Enable Flavor And Fragrance Industry". Chemical and Engineering News 81 (28): 54. Tiemann, Ferd.; Wilh. Haarmann (1874). "Ueber das Coniferin und seine Umwandlung in das aromatische Princip der Vanille". Berichte der Deutschen Chemischen Gesellschaft 7 (1): 608–623.doi:10.1002/cber.187400701193. Van Ness, J. H. (1983). "Vanillin". Kirk-Othmer Encyclopedia of Chemical Technology, 3rd edition. 23. New York: John Wiley & Sons. pp. 704–717. Viriot, Carole; Augustin Scalbert, Catherine Lapierre, and Michel Moutounet (1993). "Ellagitannins and lignins in aging of spirits in oak barrels". Journal of Agricultural and Food Chemistry 41 (11): 1872–1879. doi:10.1021/jf00035a013. Walton, Nicholas J.; Melinda J. Mayer, and Arjan Narbad (July 2003). "Vanillin". Phytochemistry 63 (5): 505– 515. doi:10.1016/S0031-9422(03)00149-3.
Notes ^ a b PubChem 1183 ^ Vanillin ^ According to Esposito 1997, blind taste-testing panels cannot distinguish between the flavors of synthetic vanillin from lignin and those from guaicol, but can distinguish the odors of these two types of synthetic vanilla extracts. Guaiacol vanillin, adulterated with acetovanillone, has an odor indistinguishable from lignin vanillin. ^ a b c d Esposito 1997 ^ Gobley 1858 ^ Tiemann 1874 ^ Reimer 1876 ^ According to Hocking 1997, synthetic vanillin was sold commercially in 1874, the same year Tiemann and Haarmanns original synthesis was published. Haarmann & Reimer, one of the corporate ancestors of the modern flavor and aroma manufacturerSymrise, was in fact established in 1874. However, Esposito 1997claims that synthetic vanillin first became available in 1894 when Rhône-Poulenc (since 1998, Rhodia) entered the vanillin business. If the former claim is correct, the authors of the latter article, being employees of Rhône-Poulenc, may have been unaware of any previous vanillin manufacture. ^ a b c d Hocking 1997 ^ Rouhi 2003 ^ "Leptotes bicolor". Flora Library. Retrieved 2011-08-21. ^ Brenes 1999 ^ Adahchour 1999 ^ Roberts 1996 ^ Ong 1998 ^ Analysis of polyphenolic compounds of different vinegar samples. Miguel Carrero Gálvez, Carmelo García Barroso and Juan Antonio Pérez-Bustamante, Zeitschrift für Lebensmitteluntersuhung und -Forschung A, Volume 199, Number 1, pages 29-31, doi:10.1007/BF01192948 ^ Viriot 1993 ^ Semmelroch, P.; Laskawy, G.; Blank, I.; Grosch, W. (1995). "Determination of potent odourants in roasted coffee by stable isotope dilution assays". Flavour and Fragrance Journal 10: 1.doi:10.1002/ffj.2730100102. edit ^ Blank 1992 ^ Kermasha 1995 ^ Buttery 1995 ^ Guth 1993
^ Walton 2003 ^ Dignum 2001 reviews several such proposed innovations in vanilla processing, including processes in which the seed pods are chopped, frozen, warmed by a heat source other than the sun, or crushed and treated by various enzymes. Whether or not these procedures produce a product whose taste is comparable to traditionally prepared natural vanilla, many of them are incompatible with the customs of the natural vanilla market, in which the vanilla beans are sold whole, and graded by, among other factors, their length. ^ Dignum 2001 ^ Hocking 1997. This chemical process can be conveniently carried out on the laboratory scale using the procedure described by Lampman 1977. ^ Van Ness 1983 ^ Japan’s 12th Ig Noble Prize Winner: Mayu Yamamoto & Dung Vanilla : Japan Probe ^ FRIDGE 2004, p. 33 ^ FRIDGE 2004, p. 32. ^ R.N. Rogers, "Studies on the Radiocarbon Sample from the Shroud of Turin", Thermochimica Acta, 2005, 425, 189-194. ^ R.N. Rogers and A. Arnoldi, "Scientific Method applied to the Shroud of Turin" ^ Saint Denis, M.; Coughtrie, MW.; Guilland, JC.; Verges, B.; Lemesle, M.; Giroud, M. (Dec 1996). "[Migraine induced by
Carvone IUPAC name 2-Methyl-5-(1-methylethenyl)-2-cyclohexenone
S-(+)-Carvone is the principal constituent (50-70%) of the oil from caraway seeds (Carum carvi), which is produced on a scale of about 10 tonnes per year. It also occurs to the extent of about 40-60% in dill seed oil (from Anethum graveolens), and also in mandarin orange peel oil.R-(–)- Carvone is also the most abundant compound in the essential oil from several species of mint, particularly spearmint oil (Mentha spicata), which is composed of 50- 80% R-(–)-carvone.Spearmint is a major source of naturally produced R-(–)-carvone. However, the majority of R-(–)-carvone used in commercial applications is synthesized from limonene.The R-(–)-carvone isomer also occurs in kuromoji oil. Some oils, like gingergrass oil, contain a mixture of both enantiomers. Many other natural oils, for example peppermint oil, contain trace quantities of carvones.
The figure below shows the structure of some common flavors and fragrances:
Valerolactone (12) composes the fragrance blend of the mostrepresentative Italian white wine varieties of Campania. In addition, itexhibits a potential antifungal property against Monilinialaxa and Rhizopus stolonifer and is also a potent inhibitor of mousecoumarin 7-hydroxylases (CYP2A5). This lactone was prepared fromthe enantioenriched hydroxy telluride (R)-10 by reaction with 2 equiv.of n-butyllitium followed by carbon dioxide. Its enantiomer, lactone(S)-12, was prepared from telluride (S)-10, by the same protocol andused as starting material in the synthesis of the E/Z isomeric mixtureof spiroketals 13a and 13b.35 This synthetic step required thepreparation of the di-cerium salt 14, generated by the addition of 2equiv. of butyllithium to a mixture of the optically active hydroxytelluride (R)-10 and cerium chloride in THF at -78 ºC. The acid / baseand tellurium / lithium exchange reactions were so fast, that eventraces of the butyl addition byproduct were not detected. Theresulting organocerium dianion was reacted with lactone (S)-12 allowing the isolation of (2R,5S,7S)-13a and (2R,5R,7S)-13b as a1:1 isomeric mixture. These compounds are constituents of the flavorof Jamaican rum (Scheme 13).35
Safrole, also known as shikimol, is a phenylpropene. It is a colorless or slightly yellow oily liquid. It is typically extracted from the root-bark or the fruit of sassafras plants in the form ofsassafras oil (although commercially available culinary sassafras oil is usually devoid of safrole via a rule passed by the FDA in 1960), or synthesized from other related methylenedioxycompounds. It is the principal component of brown camphor oil, and is found in small amounts in a wide variety of plants, where it functions as a natural pesticide. Ocotea cymbarum oil made from Ocotea pretiosa, a plant growing in Brazil, and sassafras oil made from Sassafras albidum, a tree growing in eastern North America, are the main natural sources for safrole. It has a characteristic "sweet-shop" aroma.
Safrole [5-allylbenzo[d][1,3]dioxole] (1)Safrole [5-allylbenzo[d][1,3]dioxole] (1) is the majorcomponent (80%) of the essential oil of sassafras(Piper hispidinervum) (Piperaceae) in its leaves. IRspectra were performed on a Perkin-Elmer 16 FPCFT-IR spectrophotometer as thin films. 1H-NMR and 13C-NMR spectra were obtained inCDCl3 solution with a Brucker AVANCE D.P.X.600 MHz apparatus. GCMS were determined by JoelJMS 600H, GC Hewlett Packard, HP 6890 Series, withcapillary column (30 m × 0.32 mm × 0.25 μm) HP-5cross linked 5% dimethyl polysiloxane. A sodiumlamp (Phillips G/5812 SON) was used for photo-irradiation reactions. Thin layer chromatography(TLC) and preparative layer chromatography (PLC):Polygram SIL G/W 254, Mecherey-Nagel. A rotatoryevaporator (at 20 °C 15 torr) was used to remove thesolvents.
Safrole can be synthesized in three steps from unwatched chemicals in good yield:1.Catechol (1,2-dihydroxybenzene, or pyrocatechol) is reacted in abasic solution with dibromomethane (CH2Br2) to 1,2-methylenedioxybenzene.The 1,2-methylenedioxy- benzene is selectively brominated withN-bromo- succinimide to form 4-bromo- 1,2-methylenedioxybenzene.The 4-bromo-1,2-methylenedioxy- benzene is reacted withMg to give the Grignard adduct (R-MgBr), and coupled with allyl bromide to form safrole.
In a 2L-round bottom flask with two neck adapter (reflux condenser, dropping funnel) immersed in an oil bath / magnetic stirrer, are placed 95 mL (1.36 moles) of dibromomethane, 180 mL water and 4-5 mL trioctylmethylammonium chloride (PTC, "Adogen 464, Aliquat 336"). On the top of the reflux condenser, a tube is drawn to a gas washing bottle to give some protection against the atmosphere.) The contents of the flask are heated and stirred to reflux and a previous made solution of 100 g (0.91 moles) 1,2-dihydroxybenzene (catechol), 91 g sodium hydroxide (2.275 moles) and 450 mL water is added to the flask (the contents are stirred vigorously and refluxed continously). The addition time is 120 min, thereafter the contents are stirred and refluxed 90 min. The product is distilled with steam (add water continously to flask, distill off water and product). After 1.5 liters of distillate are collected, the distillate is saturated with table salt, and extracted three times with ether (better: tert-butyl methyl ether, non watched, and not so dangerous). The etheral extracts are dried with sodium sulfate, the whole is filtered, and the drying agent washed with 2x30 mL of solvent. The combined filtrates are evaporated (rotavap), and the residue is distilled in vacuum. At 60- 80°C (20 mmHg), 87 g 1,2-methylenedioxybenzene distills, containing about 8% of unreacted dibromomethane. The gum in the reaction/distillation flasks is removed with organic solvents.
In a 500 mL-round bottom flask with reflux condenser (situated in an oil bath and with magnetic stirrer) are placed 70 g of the product from step 1 (92% pure 1,2-methylenedioxybenzene, 0.53 moles), 100 g N-bromosuccinimide and 260 mL chloroform (dry). After three hours of refluxing and stirring, the solution is cooled to room temp, and the the succinimide is filtered off with suction, and washed with 2x20 mL of chloroform. The combined filtrates are evaporated, and the residue is vacuum distilled. At 125-135°C (40 mmHg), a mixture of product and succinimide distills, which is diluted with twice the volume of diethyl ether, stored 3 hrs. over solid sodium hydroxide and washed thoroughly with water. After thorough drying over sodium sulfate, the drying agent is filtered off and washed with 20 mL diethyl ether. The ether is evaporated (rotavap), the yellow- brownish residual oil is sufficiently pure for the next step (the refractive index at 25°C is 1.583). The yield is 72 g, 67% of theory calculated to pure 1,2-methylenedioxybenzene being used.
In a 500 mL flask (immersed in a magnetic stirrer / oil bath) are placed 10-11g magnesium turnings, and 150 mL tetrahydrofuran (freshly distilled from sodium). After the addition of a little iodine crystal and 2 mL dibromomethane to start the Grignard reaction, the 72 g of 4-bromo-1,2-methylenedioxybenzene (step 2) are added to maintain gently reflux. To start up, heating of the bath to 50°C is recommended. After the addition, which takes about 60 min., the whole is stirred and refluxed 1 hr., and the brown liquid is rapidly decanted to a very dry 500 mL flask with dropping funnel and reflux condenser. The magnesium turnings are washed with additional 20 mL dry THF, the washing is added to the Grignard solution. A little (0.5 g) copper(I)iodide is added, and with cooling in an ice-bath, 40 mL (0.47 moles) allyl bromide are added dropwise, the internal temperature should not exceed 40°C. After standing overnight, followed by 1 hr of refluxing, the reaction mixture is suspended in a solution of 20 mL 37% hydrochloric acid in 500 mL water and this is added to 80 mL 25% ammonia, and the solution is steam distilled as above. After collecting 2 L distillate, the distillate is acidified to congo red (pH 4) with hydrochloric acid, saturated with table salt, and extracted with 4x200 mL ether. The combined extracts are dried with sodium hydroxide, evaporated (rotavap), and the residue taken up in ether, and washed thorougly with sodium hydroxide. After drying (sodium sulfate), the drying agent is filtered, washed with 20 mL ether, and the combined extracts are evaporated. The residue is vacuum distilled, 39 g (67% of theory) of safrole, boiling at 120-130°C (20-25 mmHg), are obtained. Colourless and typically smelling oil. Total yield (from the catechol), 32-33% of theory.
Tet. Lett. 3489-3490 (1975) J. Chem. Soc. (C), 1202-1204 (1969) J. Org. Chem. 23, 908-910 (1958) Ann. Chem. 689, 156-162 (1965) Bull. Soc. chim. France, 1892-1895 (1964)
The structure of epoxidederivative 2 was established byspectral measurements. The 1H-NMR spectrum of2 showed two doubletsignals at δ 2.75 and δ 2.80 ppm fortwo protons 2H-3′ in position 3′ , twodoublet at δ2.53 ppm and δ 2.77 ppmfor the two methylene protons CH2-1′and complex pattern at δ 3.1 ppm forproton H-2′. In the 13C-NMR spectrumof 2, signals from the oxiran carbonatoms were presented at δC 46.9 ppm((C3′) and δC 52.6 ppm ((C2′). The massspectrum of 2 contained the molecularion peak at m/z 178.
Smell flavorants, or simply, flavorants, are engineered and composed in similar ways as with industrial fragrances and fine perfumes. To produce natural flavors, the flavorant must first be extracted from the source substance. The methods of extraction can involve solvent extraction, distillation, or using force to squeeze it out. The extracts are then usually further purified and subsequently added to food products to flavor them. To begin producing artificial flavors, flavor manufacturers must either find out the individual naturally occurring aroma chemicals and mix them appropriately to produce a desired flavor or create a novel non-toxic artificial compound that gives a specific flavor. Most artificial flavors are specific and often complex mixtures of singular naturally occurring flavor compounds combined together to either imitate or enhance a natural flavor. These mixtures are formulated by flavorists to give a food product a unique flavor and to maintain flavor consistency between different product batches or after recipe changes. The list of known flavoring agents includes thousands of molecular compounds, and the flavor chemist (flavorist) can often mix these together to produce many of the common flavors. Many flavorants consist ofesters, which are often described as being "sweet" or "fruity". ChemicalOdorDiacetylButtery Isoamyl acetateBanana BenzaldehydeBitter almond Cinnamic aldehydeCinnamon Ethyl propionateFruity Methyl anthranilateGrapeL imoneneOrange Ethyl- (E,Z)-2,4-decadienoatePear Allyl hexanoatePineapple Ethyl maltolSugar, Cotton candy EthylvanillinVanilla Methyl salicylateWintergreen
While salt and sugar can technically be considered flavorants that enhance salty and sweet tastes, usually only compounds that enhance umami, as well as other secondary flavors are considered and referred to as taste flavorants. Artificial sweeteners are also technically flavorants. Umami or "savory" flavorants, more commonly called taste or flavor enhancers are largely based on amino acids and nucleotides. These are typically used as sodium or calcium salts. Umami flavorants recognized and approved by the European Union include: AcidDescriptionGlutamic acidsaltsThis amino acids sodium salt, monosodium glutamate (MSG), a notable example, is one of the most commonly used flavor enhancers in food processing. Mono and diglutamate salts are also commonly used.Glycine saltsSimple amino acid salts typically combined with glutamic acid as flavor enhancers.Guanylic acidsaltsNucleotide salts typically combined with glutamic acid as flavor enhancers.Inosinic acidsaltsNucleotide salts created from the breakdown of AMP. Due to high costs of production, typically combined with glutamic acid as flavor enhancers.5-ribonucleotidesaltsNucleotide salts typically combined with other amino acids and nucleotide salts as flavor enhancers.Certain organic and inorganic acids can be used to enhance sour tastes, but like salt and sugar these are usually not considered and regulated as flavorants under law. Each acid imparts a slightly different sour or tart taste that alters the flavor of a food.
Cold pressed citrus oils have a high content of terpene hydrocarbons, which do not contribute much to the flavor and are detrimental to the oil’s stability and solubility. Terpene hydrocarbons are usually removed by vacuum distillation, thin film evaporation or solvent extraction (a process that uses distillation to remove the solvent before use). The higher the vacuum of a still, the lower the boiling point of the oil. This principle, when extended to a short path still, results in a falling film evaporator. Nash pumps are tolerant of process upsets and can maintain constant vacuum levels under varying conditions, making sure that the desired product composition is achieved and downtime is not an issue.
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DR ANTHONY MELVIN CRASTO Ph.D firstname.lastname@example.org MOBILE-+91 9323115463GLENMARK SCIENTIST , NAVIMUMBAI, INDIA web link http://anthonycrasto.jimdo.com/ http://www.anthonymelvincrasto.yolasite.com/ http://www.slidestaxx.com/anthony-melvin-crasto-phdhttps://sites.google.com/site/anthonycrastoorganicchemistry/sites- --my-own-on-the-net http://anthonycrasto.wordpress.com/ http://organicchemistrysite.blogspot.com/ http://www.mendeley.com/profiles/anthony-melvin-crasto/ Congratulations! Your presentation titled "Anthony Crasto Glenmark scientist, helping millions with websites" has just crossed MILLION views.