- Hydrometalation
Hydrometalation hydrometallation is a type of chemical reaction in organometallic chemistry in which a chemical compound with a hydrogen to metal bond M H, metal hydride adds to a compounds with an saturation chemistry unsaturated bond like an alkene RC CR forming a new compound with a carbon to metal bond RHC CRM . ref Elschenbroich, C. Organometallics 2006 Wiley VCH Weinheim. ISBN 3527293906 ref The metal is less electronegative than hydrogen, the reverse reaction is beta hydride elimination . The reaction is structurally related to carbometalation . When the substrate is an alkyne the reaction product is a vinylorganometallic. Image Hydrometalation.svg Hydrometalation of an alkene Examples are hydroboration , hydrosilylation and hydrozirconation . References Reflist Category Organometallic chemistry ... more details
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- Maya Mountain
Maya Mountain coor dm 77 47 S 160 33 E is a small pyramidal mountain , about 2,000 m high, between Aztec Mountain and Pyramid Mountain , just south of Taylor Glacier in Victoria Land . So named by the New Zealand Geological Survey Antarctic Expedition NZGSAE 1958 59 because its shape resembles the pyramidal ceremonial platforms used by the Mayan civilization. usgs gazetteer Category Mountains of Victoria Land Category Scott Coast ScottCoast geo stub ... more details
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- Basal dendrite
unreferenced date July 2008 A basal dendrite is a dendrite that emerges from the base of a pyramidal cell that receives information from nearby neurons and passes it to the soma, or cell body. Category Cerebrum Category Neurons neuroanatomy stub ... more details
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- Lamina pyramidalis externa
Unreferenced date December 2006 Orphan date February 2009 Lamina pyramidalis externa is layer 3, or the cortex cerebri external pyramidal layer of cortex cerebri . DEFAULTSORT Lamina Pyramidalis Externa Category Neuroanatomy Neuroanatomy stub ... more details
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- Lamina pyramidalis interna
Unreferenced date December 2006 Orphan date February 2009 Lamina pyramidalis interna is layer 5, or the cortex cerebri internal pyramidal layer of cortex cerebri . DEFAULTSORT Lamina Pyramidalis Interna Category Neuroanatomy Neuroanatomy stub ... more details
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- Mercury(II) acetate
The Hg sup 2 sup center binds to alkene s, inducing the addition of hydroxide and alkoxide . For example ... more details
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- 20000 (number)
square pyramidal number 26214 octahedral number 26227 cuban prime 26861 smallest number below which there are more primes of the form 4k 1 than of the form 4k 3 27434 square pyramidal number 27559 Zeisel ... number 28158 pentagonal Pentagonal pyramidal number pyramidal number 28374 smallest integer to start ... 29341 Carmichael number 29370 square pyramidal number Category Integers 299e04 20000 az 20000 ... more details
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- 2,3-sigmatropic rearrangement
Unreferenced date December 2009 2,3 Sigmatropic rearrangements are a type of sigmatropic rearrangement s and can be classified into two types. Rearrangements of allyl ic sulfoxide s, amine oxide s, selenoxide s are pH neutral . Rearrangements of carbanion s of allyl ether s are anionic . The general scheme for this kind of rearrangement is Image 2,3 sigmatropic rearrangement.svg center Atom Y may be sulfur , selenium , or nitrogen . If Y is nitrogen, the reaction is referred to as a Stevens rearrangement 2,3 Stevens rearrangement if Y is oxygen, then it is called a Wittig rearrangement 2,3 Wittig rearrangement not to be confused with the well known Wittig reaction , which involves a phosphonium ylide . File Sulfoxide rearrangement.svg center A 2,3 rearrangement may result in carbon carbon bond formation. It can also be used as a ring expansion reaction ring expansion reaction. Image ringenlarge.png center Stereoselectivity 2,3 Sigmatropic rearrangements can offer high stereoselectivity . At the newly formed double bond there is a strong preference for formation of the E alkene or trans isomer product. The stereochemistry of the newly formed C C bond is harder to predict. It can be inferred from the five membered ring transition state . Generally, the E alkene will favor the formation of anti addition anti product , while Z alkene will favor formation of syn addition syn product. Image 23stereochem.png center Diastereoselectivity can be high for Z alkene with alkynyl, alkenl, or aryl anion stabilizing group. Diastereoselectivity is usually lower with E alkenes. Hydrocarbon groups will prefer exo isomer exo orientation in the envelope like transition state. Anion stabilizing group will prefer the endo isomer endo orientation in transition state. DEFAULTSORT 2,3 Sigmatropic Rearrangement Category Rearrangement reactions Category Reaction mechanisms es Rearreglo sigmatr pico 2,3 ... more details
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- C3H4
DISPLAYTITLE C sub 3 sub H sub 4 sub C sub 3 sub H sub 4 sub may refer to Compounds sharing the molecular formula Cyclopropene , a cyclic alkene Methylacetylene , a common alkyne Propadiene , an allene MolFormDisambig el C3H4 fr C3H4 it C3H4 nl C3H4 ja C3H4 sr C3H4 zh C3H4O ... more details
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- Metal acetylacetonates
group, and many related compounds are known. The molecule is square pyramidal, with idealized ... of other ligands affords mixed ligand complexes, e.g. Ru acac sub 2 sub alkene sub 2 sub .... last4 Kovacik first4 I. last5 Willis first5 A. C. year 1998 title Alkene Complexes of Divalent and Trivalent Ruthenium Stabilized by Chelation. Dependence of Coordinated Alkene Orientation on Metal ... O m.p. 138 140 C is pentacoordinate, adopting a square pyramidal structure. ref cite journal ... more details
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- Koch reaction
The Koch reaction is an organic reaction for the organic synthesis of certain tertiary carboxylic acid s from an alkene , carbon monoxide and water ref Arpe, .J. Industrielle organische Chemie Bedeutende vor und Zwischenprodukte , 2007 , Wiley VCH Verlag, ISBN 3527315403 ref . Image Schemata der Koch Reaktion V.svg 700px The Koch reaction This process is used on an industrial scale with annual production of 150.000 tons. When the substrate a substituted alkene is isobutene the applied pressure is between 5 10 sup 5 sup and 10 sup 7 sup Pascal unit Pa and the temperature between 0 C and 50 C. The acidic catalyst is a mixture of phosphoric acid and boron trifluoride . This reaction is a hydroformylation followed by hydrolysis . Some industrially produced carboxylic acids are 2,2 dimethylpropionic acid pivalic acid , 2,2 dimethylbutyric acid and 2,2 dimethylpentanoic acid. References Reflist DEFAULTSORT Koch Reaction Category Addition reactions Category Name reactions de Koch Reaktion it Reazione di Koch kk nl Koch reactie zh Koch ... more details
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- Thioenol
Thioenols also known as alkenthiols are alkene s with a thiol group affixed to one of the carbon atoms composing the double bond . Alkenes with a thiol group on both sides of the double bond are called enedithiols . Deprotonation Deprotonated anions of thioenols are called thioenolates . The C C double bond with adjacent alcohol gives thioenols and enedithiols their chemical characteristics, by which they present keto enol tautomerism . In keto enol tautomerism, thioenols interconvert with thioketone s or thioaldehyde s. The words thioenol and alkenthiol come from the words alkene or just ene , the suffix given to C C double bonded alkenes and thiol which represents the thioenol s thiol group . Thioketo thioenol tautomerism Thioenols interconvert with thio carbonyl compound s that have an hydrogen , like thioketone s and thioaldehyde s. The compound is Deprotonation deprotonated on one side and Protonation protonated on another side, whereas a single bond and a double bond are exchanged. This is called keto enol tautomerism . See also Enol External links http www.nrcresearchpress.com doi abs 10.1139 v98 027 Canadian journal of chemistry Category Sulfur compounds ... more details
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- Brodmann area 12
Infobox Brain Name Brodmann area 12 Latin boxwidth GraySubject GrayPage Image Brodmann Cytoarchitectonics 12.png Width 250 Caption Brodmann area 12 shown in orange Image2 Gray726 Brodman.svg Caption2 Image of brain with Brodmann areas numbered IsPartOf Components Artery Vein Acronym BrainInfoType BrainInfoNumber MeshName MeshNumber NeuroLex Brodmann area 12 NeuroLexID birnlex 1743 Dorlands DorlandsID Brodmann area 12 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture . It occupies the most rostral portion of the frontal lobe . Brodmann 1909 did not regard it as homology biology homologous , either topographical ly or cytoarchitecturally, to rostral area 12 of the human. Distinctive features Brodmann 1905 a quite distinct internal granular layer IV separates slender pyramidal cell s of the external pyramidal layer III and the internal pyramidal layer V the multiform layer VI is expanded, contains widely dispersed spindle cell s and merges gradually with the underlying cortical white matter all cells, including the pyramidal cells of the external and internal pyramidal layers are inordinately small the internal pyramidal layer V also contains spindle cells in groups of two to five located close to its border with the internal granular layer IV . Image gallery File Brodmann area 12 animation small.gif Animation. File Brodmann area 12 frontal.jpg Frontal view. File Brodmann area 12 medial.jpg Medial view. gallery See also Brodmann area List of regions in the human brain External links For Neuroanatomy of this area see http braininfo.rprc.washington.edu Scripts ancilcentraldirectory.aspx?ID 59 BrainInfo Prosencephalon Category Brodmann areas 12 neuroanatomy stub ... more details
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- Peterson olefination
to form the desired alkene. The penta coordinate silicate intermediate 3 is postulated, but no proof ... results in protonation and an anti elimination to form the desired alkene. Image Peterson Acidic ..., E. M. collvol 9 collvolpages 580 year 1998 prep cv9p0580 title nowiki Stereoselective Alkene Synthesis ... is treated with acid, while the other is treated with base, thus converted the material to an alkene ... contains electron withdrawing substituents, the Peterson olefination directly forms the alkene. The intermediate ... alkene. ref name chan1974 cite journal author T. H. Chan and E. Chang title Synthesis of alkenes from ... more details
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- Citroën Karin
The Citro n Karin was a concept car presented at the Mondial de l Automobile Paris Motor Show in 1980. It featured a striking, pyramidal design and was designed by Trevor Fiore . Citro n External link http www.citroenet.org.uk prototypes karin karin.html Category Citro n concept vehicles Karin Modern auto stub fr Citro n Karin ... more details
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- Csomafalvi-Dél-hegy
multiple issues cleanup March 2009 unreferenced March 2009 orphan December 2010 Amza , in Harghita County , Romania , is the highest Pyramidal peak peak in the Southern Gurghiu Mountains . It is part of the rim of an extinct volcanic crater . coord missing Romania Category Mountains of Romania Romania geo stub ... more details
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- Pterygoid notch
expand further date February 2012 Pterygoid notch incisura pterygoidea a notch on the inferior portion of the pterygoid processes of the sphenoid bone, between the medial and lateral plates into which the pyramidal process of the palatine bone is fitted. Anatomy stub Category Bones of the head and neck ro Incizur pterigoidian ... more details
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- Angle strain
and pyramidal alkene s. Some specific examples are cyclopropane , C sub 3 sub H sub 6 sub &mdash ... more details
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- Stratum lucidum of hippocampus
Infobox Brain Name PAGENAME Latin stratum lucidum hippocampi GraySubject GrayPage Image Caption Image2 Caption2 IsPartOf Components Artery Vein Acronym BrainInfoType ancil BrainInfoNumber 975815906 MeshName MeshNumber NeuroLex Stratum lucidum NeuroLexID birnlex 4108 DorlandsPre s 25 DorlandsSuf 12761360 For the layer of the skin, see stratum lucidum . The stratum lucidum of the hippocampus is also a layer of the hippocampus between the stratum pyramidale and the stratum radiatum . It is the tract of the mossy fiber projections, both inhibitory and excitatory from the granule cells of the dentate gyrus . One mossy fiber may make up to 37 connections to a single pyramid cell, and innervate around 12 pyramidal cells on top of that. Any given pyramidal cell in the stratum lucidum may get input from as many as 50 granule cells. Gray s neuroscience stub Category Nervous system ... more details
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- Aztec Mountain
Aztec Mountain is a small pyramidal mountain over convert 2000 m high, just southwest of Maya Mountain and west of Beacon Valley in Victoria Land . It was so named by the New Zealand Geological Survey Antarctic Expedition 1958&ndash 59 because its shape resembles the Mesoamerican pyramids pyramidal ceremonial platforms used by the Aztec and Maya civilization Maya civilizations. coord 77 48 S 160 31 E source GNIS display title See also Altar Mountain Maya Mountain References usgs gazetteer id 800 Category Mountains of Victoria Land Category Scott Coast ScottCoast geo stub ... more details
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- Lalouette's pyramid
Lalouette s pyramid is a pyramidal extension of the thyroid gland, described by Pierre Lalouette in 1743 ref cite news first last coauthors authorlink title A la d couverte de la thyro de date publisher Pierre and Marie Curie University UPMC url http www.chups.jussieu.fr polys histoire medecine histoiredelathyroide histthyrodia.pdf work pages 39 accessdate 2 March 2009 language French ref . Lalouette s pyramid is seldom present in representations of the thyroid. See Also Pyramidal lobe of thyroid gland References Reflist Category Endocrine system anatomy stub ... more details
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- Bekhterev?Mendel reflex
The Bekhterev Mendel reflex , also known as the Mendel reflex or Mendel Bekhterev reflex , is a Medical sign clinical sign found in patients with Upper motor neurone lesion pyramidal tract lesions . Percussion medicine Percussion of the Dorsum biology dorsum of the foot causes flexion , or downward movement, of the 2nd to the 5th toes in patients with pyramidal tract lesions, whereas percussion of the dorsum of the foot in normal patients causes Extension kinesiology extension of the toes. It is analogous to the Bekhterev Jacobsohn reflex in the upper limb. The reflex is named after Vladimir Bekhterev and Kurt Mendel . External links WhoNamedIt synd 1667 Mendel s reflex med sign stub Category Medical signs Category Reflexes ru ... more details
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- Decussation of pyramids
Infobox Brain Name Decussation of pyramids Latin Decussation decussatio pyramidum GraySubject 192 GrayPage 870 Image Gray684.png Caption Deep dissection of brain stem. Lateral view. pyramidal tract visible in red, and pyramidal decussation labeled at lower right. Image2 Caption2 IsPartOf Components Artery Vein BrainInfoType hier BrainInfoNumber 796 MeshName MeshNumber NeuroLex Pyramidal decussation NeuroLexID birnlex 1594 DorlandsPre d 04 DorlandsSuf 12282126 The two Pyramid of medulla oblongata pyramids contain the motor fibers that pass from the brain to the medulla oblongata and medulla spinalis , corticobulbar and corticospinal fibers. When these pyramidal fibers are traced downward, it is found that some three fifths or more of them leave the pyramids in successive bundles, and decussate in the anterior median fissure of the medulla oblongata , forming what is termed the pyramidal decussation or motor decussation . Having crossed the middle line, they pass down in the posterior part of the lateral funiculus as the lateral cerebrospinal fasciculus . Additional images gallery Image Gray663.png Diagrams of the medulla spinalis. Image Gray679.png Medulla oblongata and pons. Anterior surface. Image Gray680.png Decussation of pyramids. Scheme showing passage of various fasciculi from medulla spinalis to medulla oblongata. Image Gray687.png Section of the medulla oblongata through the lower part of the decussation of the pyramids Image Gray688.png Section of the medulla oblongata at the level of the decussation of the pyramids. Image Gray689.png Superficial dissection of brain stem. Ventral view. Image Gray764.png The motor tract. Image Human brain frontal coronal section description 2.JPG Human brain frontal coronal section gallery External links AnatomyAtlasesMicroscopic 17 326 Medula Oblongata Gray s Rhombencephalon Neural tracts Category Neuroanatomy neuroscience stub ... more details
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- 40000 (number)
Number number 40000 range 10000 100000 cardinal 40000 ordinal th ordinal text forty thousandth factorization math 2 6 cdot 5 4 math bin 1001110001000000 oct 116100 hex 9C40 40,000 forty thousand is the number that comes after 39,999 and before 40,001. It is the square of 200. Selected numbers 40000 round number 40320 smallest factorial that is not a highly composite number 40425 square pyramidal number 40585 largest factorion 40678 pentagonal pyramidal number 40804 palindromic number palindromic square 41041 Ryle number 41616 triangular square number 41835 Motzkin number 42680 octahedral number 42925 square pyramidal number 43261 Markov number 43560 pentagonal pyramidal number 43691 Wagstaff prime 44100 sum of the cubes of the first 20 positive integers, sampling rate of Red Book compliant audio compact disks 44721 When n 44721, the expression 1 n 1 n 2 drops down to fractions of a billionth. The corresponding sum in the Leibniz formula for pi is 0.785386986. 44944 palindromic square 45360 first number to have 100 factors including one and itself 46233 sum of the first eight factorials 46368 Fibonacci number 46656 math 6 6 math 46657 Carmichael number 46664 number 46664 Nelson Mandela s prisoner number 46853 Number of customers in the SpongeBob SquarePants episode Patty Hype 47058 primary pseudoperfect number 47806 in hexadecimal it is written as BABE 49151 Woodall number 49726 pentagonal pyramidal number Category Integers 49e04 40000 az 40000 d d fa fr 40 000 nombre ms 40000 nombor ja 40000 ... more details
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- Electromeric effect
Multiple issues intromissing August 2009 unreferenced August 2009 orphan September 2010 wikify January 2011 Electromeric effect refers to a temporary polarization between atoms in a multiple bond in the presence of an attacking reagent. The effect is temporary and it will revert when the reagent is removed.The electron transfer facilitates the bonding of the attacking group to the atom. If the transfer is towards the attacking group, it is indicated as E and if it is away from the attacking group, it is termed as E. Consider addition of proton to an alkene, say ethene CH2 CH2 . Before the attack of the reagent the pi electrons are uniformly distributed between the two carbon atoms. When the proton approaches the alkene, the pi electron density of the alkene gets shifted towards one of the carbon atoms creating a positive charge on one carbon and negative on the other and it is this pair of electrons which is then utilized to form a bond with the proton. The effect thus helps in the reaction. If the attacking reagent proton, in this case is removed the effect disappears, proving the temporary nature of the effect. As another example, consider the carbonyl group, C O, present in electromeric effect aldehydes and ketones. When a negatively charged reagent approaches the molecule seeking positive site, it causes instantaneous shift of the bond electron pair of the C O bond in carbonyl group to oxygen which is more electronegative than carbon . The carbon then acquires positive charge. In the meanwhile oxygen takes complete control of the electron pair and becomes negatively charged. Therefore, in the presence of attacking reagent, one bond is lost and this negatively charged attacking reagent links to the carbon having positive charge. Nowadays electromeric effect is often considered along with inductive effect as electron displacement. Category Physical organic chemistry Category Chemical bonding Organic chem stub ... more details
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