VITAMIN E VISITED

The α-tocopherol form of vitamin E

Vitamin E refers to a group of eight fat-soluble compounds that include both tocopherolsand tocotrienols.[1] There are many different forms of vitamin E, of which γ-tocopherol is the most common in the North American diet.[2] γ-Tocopherol can be found in corn oil, soybean oil, margarine and dressings.[3][4] In the North American diet, α-Tocopherol, the most biologically active form of vitamin E, is the second most common form of vitamin E. This variant of vitamin E can be found most abundantly in wheat germ oil, sunflower, and safflower oils.[4][5] It is a fat-soluble antioxidant that stops the production of reactive oxygen species formed when fat undergoes oxidation.[6][7][8]

  • Synthesis of Vitamin E

Vitamin E (CAS NO.: 59-02-9), with other names as 2(R),5,7,8-Tetramethyl-2-[4(R),8(R),12-trimethyltridecyl]-3,4-dihydro-2H-1-benzopyran-6-ol, could be produced through the following synthetic routes.

 Synthesis of Vitamin E
           Synthesis of Vitamin E
The chlorination of myrcene (I) with Cl2 in refluxing pentane gives the choromyrcene (II), and the hydrochlorination of (I) catalyzed by CuCl yields a mixture of geranyl/neryl chloride (III). The reductive coupling of (II) and (III) by means of Mg and CuCl affords beta-springene (IV), which is condensed with 2,3,6-trimethylhydroquinone (V) by means of cyclooctadienyl rhodium chloride dimer [RhCl(COD)]2 and K2CO3 in refluxing toluene to provide the adduct (VI). The cyclization of (VI) by means of MeAlCl2 of Ts-OH in refluxing hexane furnishes the tocotrienol (VII), which is finally hydrogenated with H2 over Pd/C in ethanol to give the target (rac)-vitamin E.

 References

  1. Brigelius-Flohe, B; Traber (1999). “Vitamin E: function and metabolism”. FASEB 13: 1145–1155.
  2. Traber, MG (1998). “The biological activity of vitamin E”. The Linus Pauling Institute. Retrieved 6 March 2011.
  3. Bieri, JG; Evarts (1974). “γ-Tocopherol: metabolism, biological activity and significance in human vitamin E nutrition”. American Journal of Clinical Nutrition 27 (9): 980–986. PMID 4472121.
  4. Brigelius-Flohé R, Traber MG (1 July 1999). “Vitamin E: function and metabolism”. FASEB J. 13 (10): 1145–55. PMID 10385606.
  5. Reboul E, Richelle M, Perrot E, Desmoulins-Malezet C, Pirisi V, Borel P (15 November 2006). “Bioaccessibility of carotenoids and vitamin E from their main dietary sources”. Journal of Agricultural and Food Chemistry 54 (23): 8749–8755. doi:10.1021/jf061818s.PMID 17090117.
  6. National Institute of Health (4 May 2009). “Vitamin E fact sheet”.
  7. Herrera; Barbas, C (2001). “Vitamin E: action, metabolism and perspectives”. Journal of Physiology and Biochemistry 57 (2): 43–56.doi:10.1007/BF03179812PMID 11579997.
  8. Packer L, Weber SU, Rimbach G (2001). “Molecular aspects of α-tocotrienol antioxidant action and cell signalling”Journal of Nutrition 131 (2): 369S–73S. PMID 11160563.

TRAP CO2 FROM FLUE GASES

Synthesis of cyclic carbonates from epoxides and carbon dioxide using bimetallic aluminum(salen) complexes

ARKIVOC Volume 2012 – Part (i): Special Issue ‘Reviews and Accounts’
Synthesis of cyclic carbonates from epoxides and carbon dioxide using bimetallic aluminum(salen) complexes (12-7669LU)
Michael North
Full Text: PDF (669K)
pp. 610 – 628

http://www.arkat-usa.org/get-file/45639/

READ FULL ARTICLE

Abstract
Over the last six years, highly active catalysts for the synthesis of cyclic carbonates from epoxides and carbon dioxide have been developed. Initial studies showed that bimetallic aluminium(salen) complexes [Al(salen)]2O formed active catalysts and kinetic studies allowed the catalytic cycle to be determined. The catalysts could be immobilized on silica, allowing them
to be used in a gas phase flow reactor as well as in batch reactors. The compatibility of the catalysts with waste carbon dioxide present in power station flue gas has been investigated and studies to enhance the commercial applicability of the catalysts by reducing the cost of their
production carried out

ANTI CANCER COMPOUNDS

Anticancer activity 

Most of the tested compounds exploited potent to moderate growth inhibitory activity, in particular compound 11d, which exhibited superior potency to the reference drug Doxorubicin. The structures of the compounds obtained were determined by spectroscopic data.

Arch Pharm Res. 2012 Nov;35(11):1909-17. doi: 10.1007/s12272-012-1107-6. Epub 2012 Dec 4.

Synthesis and anticancer activity of some novel fused pyridine ring system.

Elansary AKMoneer AAKadry HHGedawy EM.

Source

Pharmaceutical Organic Chemistry Department, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt.

Abstract

New series of pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidines (7a,b) and thieno[2,3-b:4,5-b’] dipyridine (11a-c) were synthesized from 4-aryl-6-(4-chlorophenyl)-2-thioxo-1,2-dihydro pyridine-3-carbonitriles 4a,b via application of Thorpe-Zielger reaction. The novel target compounds were evaluated in vitro for their anticancer activity against human breast adenocarcinoma MCF-7 and colon carcinoma cell line (HCT 116). Most of the tested compounds exploited potent to moderate growth inhibitory activity, in particular compound 11d, which exhibited superior potency to the reference drug Doxorubicin (IC(50) = 5.95, 6.09 and 8.48, 8.15 μM, respectively). The structures of the compounds obtained were determined by spectroscopic data.

link

http://www.ncbi.nlm.nih.gov/pubmed/23212632

Reaction of 2-bromo-2-phenyl-1,1-dichlorocyclopropane with phenols and alcohols

Physical propertiesReaction of 2-bromo-2-phenyl-1,1-dichlorocyclopropane with phenols and alcohols
Journal
Title
Reaction of 2-bromo-2-phenyl-1,1-dichlorocyclopropane with phenols and alcohols
DOI
10.1134/S0012500812080022
Kurbankulieva, E. K.;Kazakova, A. N.;Zlotskii, S. S.
  • Original Russian Text © E.K. Kurbankulieva, A.N. Kazakova, S.S. Zlotskii, 2012, published in Doklady Akademii Nauk, 2012, Vol. 445, No. 4, pp. 419–420.

The reaction was done in sodium hydroxide and DMF for 2 hrs at 20 deg centigrade to yield product in 70% yield

IN ONE CASE SODIUM WAS USED IN PLACE OF NaOH

Physical properties

Pinnick Oxidation

The Pinnick oxidation is also known as Lindgren oxidation. It is an organic reaction by which aldehydes can be oxidized into its corresponding carboxylic acid, originally developed by Lindgren and Nilsson.ref1      The typical reaction condition used today was modified by G. A. Kraus even before Pinnick.ref2,3  Pinnick proved this condition as general. There are number of ways to oxidize the aldehydes however, only few reactions are endurable to the broad range of functional groups. One of such reaction is Pinnick Oxidation which can provide preferred transformation even to systems that contain sensitive functionalities or sterically hindered groups. This reaction is especially useful for oxidizing α-methylene aldehyde units.ref4 It is an inexpensive method for effectively oxidizing aldehydes instereospecific manner. The reaction is named after chemist H.W. Pinnick.

PinnickOxidationReaction
Mechanism

Following reaction mechanism was proposed for Pinnick Oxidation. However, the mechanism follows formation of a by-product that can cause a side reaction which can inevitably consume NaClO2. Therefore, the reaction requires the use of scavengers to be able to remove the by-products.ref 6

PinnickOxidationMechanism
Scope

Synthetic Uses

Zaragozic acid is a potent squalene synthase inhibitor that can reduce the side effects caused by cholesterol inhibiting drugs which can also interfere with the production of important steroids. The total synthesis of Zaragozic acid applied by A. Armstrong was possible through Pinnick Oxidation. Different oxidation methods such as Jones oxidation, modified Ley Oxidation were also applied. However, the efforts resulted in a mixture of products. A good yield with good purity could be obtained via Pinnick Oxidation.

zaragozic acid

References

  1. Lindgren, Bengt O.; Nilsson, Torsten; Husebye, Steinar; Mikalsen, ØYvind; Leander, Kurt; Swahn, Carl-Gunnar (1973). “Preparation of Carboxylic Acids from Aldehydes (Including Hydroxylated Benzaldehydes) by Oxidation with Chlorite”. Acta Chemica Scandinavica 27: 888. doi:10.3891/acta.chem.scand.27-0888.
  2. George A. Kraus; Bruce Roth (1980). “Synthetic studies toward verrucarol. 2. Synthesis of the AB ring system”. The Journal of Organic Chemistry 45: 4825. doi:10.1021/jo01312a004.
  3. George A. Kraus; Michael J. Taschner (1980). “Model studies for the synthesis of quassinoids. 1. Construction of the BCE ring system”.The Journal of Organic Chemistry 45: 1175. doi:10.1021/jo01294a058.
  4. Bal, B. S.; Childers, W.E.; Pinnick, H.W. (1981). “Oxidation of α,β-Unsaturated Aldehydes”. Tetrahedron 37: 2091–2096.doi:10.1016/S0040-4020(01)97963-3.
  5. Mundy, B.J; Michael G. Ellerd, Frank G. Favaloro (2005). Name reactions and reagents in organic synthesis. John Wiley & Sons. ISBN 0-471-22854.

 6  Corey, E.J; K.C. Nicolaou (2005). Strategic Applications of Named Reactions. Elsevier, Inc. ISBN 978-7-03-019190-8.

Physical properties

Synthesis of highly substituted pyrroles using ultrasound in aqueous media

A two-step protocol for the synthesis of highly substituted pyrroles in aqueous media and without catalyst is described. The first step is the dimerization of a 1,3-dicarbonyl compound by ceric ammonium nitrate/ultrasound to produce a tetracarbonyl derivative. This derivative is then combined with an amine in the absence of any catalysts to obtain the pyrrole via a Paal–Knorr reaction. This route is an improvement when compared with classical methodologies toward Green Chemistry objectives.
Synthesis of highly substituted pyrroles using ultrasound in aqueous media
 Instituto de Química, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos, 149 – 21941-909 Rio de Janeiro, Rio de Janeiro, Brazil

Green Chemistry Letters and Reviews, 2012, 1-5

Pyrroles are heterocycles, which are present in natural molecules such as porphyrins and bilirubins 1–4 and many other compounds that possess antioxidant 5, antitumor 6–8, and anticancer 9 10 properties. The classic methods for the synthesis of pyrroles described in the literature are Knorr 11–14, Hantzsch 15, Paal–Knorr 16–20, and Barton–Zard21 22 reactions. The Paal–Knorr reaction, in which 1,4-dicarbonyl compounds react with primary amines under slightly acidic conditions, is a very attractive approach. Ranu et al. reported a process in aqueous media catalyzed by a water-tolerant Lewis acid that can lead to penta-substituted pyrroles 23.

In the literature, there is an effort to optimize this methodology leading to environmentally friendly processes. Current publications describe the use of solvent-free conditions with Lewis acid catalysts 24, microwave heating 25 26, ionic liquids 27, and ultrasound 28. Most of these processes lead to tri- and tetra-substituted pyrroles.
supp file, copy paste link