Hydride Shift

   

                 

GREEN (Cl) = nucleophile     BLUE (OH) = leaving group     ORANGE (H) = hydride shift proton         RED(H) =remaining proton

Hydride Shift

        

      

GREEN (Cl) = nucleophile     BLUE (OH) = leaving group     ORANGE (H) = hydride shift           proton  RED(H) = remaining proton

DIWALI WISHES

            SEARCHED MANY GARDENS

                          I Searched Many Gardens
                         To Select A Flower To Give U
                         As My Diwali Gift.
                         But, I Didn't Find Any Flower
                         Beautiful Than Ur Smile. 



                         So Keep smiling. 

                                * Happy Diwali *

Mechanism of Na/K pump

Sodium-Potassium pumps

Active transport is responsible for cells containing relatively high concentrations of ions but low concentrations of sodium ions. The mechanism responsible for this is the sodium-potassium pump, which moves these two ions in opposite directions across the plasma membrane. This was investigated by following the passage of radioactively labeled ions across the plasma membrane of certain cells. It was found that the concentrations of sodium and potassium ions on the two other sides of the membrane are interdependent, suggesting that the same carrier transports both ions. It is now known that the carrier is an ATP-ase and that it pumps three sodium ions out of the cell for every two potassium ions pumped in.

Function

The Na⁺/K⁺-ATPase helps maintain resting potential, avail transport, and regulate cellular volume.^{[citation needed]} It also functions as signal transducer/integrator to regulate MAPK pathway, ROS, as well as intracellular calcium. For most animal cells, the Na⁺/K⁺-ATPase is responsible for 1/3 of the cell's energy expenditure. For neurons, the Na⁺/K⁺-ATPase is responsible for 2/3 of the cell's energy expenditure. ^{[citation needed]}

Functioning as signal transducer

Within the last decade, many independent labs have demonstrated that, in addition to the classical ion transporting, this membrane protein can also relay extracellular ouabain-binding signalling into the cell through regulation of protein tyrosine phosphorylation. The downstream signals through ouabain-triggered protein phosphorylation events include to activate the mitogen-activated protein kinase (MAPK) signal cascades, mitochondrial reactive oxygen species (ROS) production, as well as activation of phospholipase C (PLC) and inositol triphosphate (IP3) receptor (IP3R) in different intracellular compartments.^[1]
Protein-protein interactions play very important role in Na⁺-K⁺ pump-mediated signal transduction. For example, Na⁺-K⁺ pump interacts directly with Src, a non-receptor tyrosine kinase, to form a signaling receptor complex.^[2] Src kinase is inhibited by Na⁺-K⁺ pump, while, upon ouabain binding, Src kinase domain will be released and then activated. Based on this scenario, NaKtide, a peptide Src inhibitor derived from Na⁺-K⁺ pump, was developed as a functional ouabain antagonist.^[3] Na⁺-K⁺ pump also interacts with ankyrin, IP3R, PI3K, PLC-gamma and cofilin.^[4]

 Mechanism

• The pump, with bound ATP, binds 3 intracellular Na⁺ ions.
• ATP is hydrolyzed, leading to phosphorylation of the pump at a highly conserved aspartate residue and subsequent release of ADP.^{[citation needed]}
• A conformational change in the pump exposes the Na⁺ ions to the outside. The phosphorylated form of the pump has a low affinity for Na⁺ ions, so they are released.^{[citation needed]}
• The pump binds 2 extracellular K⁺ ions. This causes the dephosphorylation of the pump, reverting it to its previous conformational state, transporting the K⁺ ions into the cell.^{[citation needed]}
• The unphosphorylated form of the pump has a higher affinity for Na⁺ ions than K⁺ ions, so the two bound K⁺ ions are released. ATP binds, and the process starts again.
• 
  

SPIRO COMPOUNDS

SP-1 Compounds with only monocyclic ring components
SP-1.1 Monospiro hydrocarbons with two monocyclic rings are named by the prefix spiro before a von Baeyer descriptor (indicating the numbers of carbon atoms linked to the spiro atom in each ring in ascending order and separated by a full stop) placed in square brackets and then the name of the parent hydrocarbon indicating the total number of skeletal atoms e.g. spiro[4.4]nonane.
SP-1.2 Monospiro hydrocarbons with two monocyclic rings are numbered consecutively starting in the smaller ring at an atom next to the spiro atom, proceeding around the smaller ring back to the spiro atom and then round the second ring.
Example:


spiro[4.5]decane
not spiro[5.4]decane

SP-1.3 Heteroatoms are indicated by replacement prefixes (rules B-4.2, B-6.1, 5 and rules R-1.2.2.1 and R-9.3, ref 6) and unsaturation is indicated in the usual way (rule A-11.3, ; R-3.1.1, ) by the endings ene, diene, etc.

Examples:


8-azaspiro[4.5]dec-2-ene

spiro[4.4]nona-2,7-diene

3,9-diazaspiro[5.5]undecane
SP-1.4 Unbranched polyspiro hydrocarbons composed of only monocyclic rings are named using dispiro-, trispiro-, etc. indicating the total number of spiro atoms present and the name of the parent hydrocarbon corresponding

NAMING OF BICYLO ORGANIC COMPOUNDS

Bridged Hydrocarbons

Rule A-1. Bicyclic Systems
1.1 - Saturated alicyclic hydrocarbon systems consisting of two rings only, having two or more atoms in common, take the name of an open chain hydrocarbon containing the same total number of carbon atoms preceded by the prefix "bicyclo-". The number of carbon atoms in each of the three bridges connecting the two tertiary carbon atoms is indicated in brackets in descending order.

Examples to Rule A-1.1

1.2 - The system is numbered commencing with one of the bridgeheads, numbering proceeding by the longest possible path to the second bridgehead; numbering is then continued from this atom by the longer unnumbered path back to the first bridgehead and is completed by the shortest path from the atom next to the first bridgehead.

Examples to Rule A-1.2

1.3 - Unsaturated hydrocarbons are named in accordance with the principles set forth in Rule A-11.3 When after applying Rule A-1.2 a choice in numbering remains unsaturation is given the lowest numbers.

Examples to Rule A-1.3

(See Rule A-.1 for double locants)

1.4 - Radicals derived from bridged hydrocarbons are named in accordance with the principles set forth in Rule A-11 The numbering of the hydrocarbon is retained and the point or points of attachment are given numbers as low as is consistent with the fixed numbering of the saturated hydrocarbon.

Examples to Rule A-1.4

MCQs