Sodium—lithium exchange

Gast, R. G. and W. D. Klobe. 1971. Sodium-lithium exchange equilibria on vermiculite at 25° and 50 °C. Clays Clay Miner. 19 311-319. 

The Affective Disorders Manic Depressive Psychoses Lithium in the Affective Disorders A. Side Effects Chemistry Isotopes of Lithium Inorganic Biochemistry Mechanisms of Action Lithium and the Phosphoinositide Signaling System Lithium and the Cell Membrane A. Sodium-Lithium Exchange Anion Exchange Leak... 

Five pathways for lithium transport in erythrocytes have been described [34] (1) sodium-lithium exchange, (2) anion exchange, (3) leak, (4) sodium-potassium ATPase, and (5) sodium-potassium cotransport. Lithium-sodium countertransport (LSC), anion exchange, and the leak mechanism are thought to be the most important transport routes for lithium in vivo [34]. All are potentially bidirectional, but the overall direction of flow under physiological conditions is efflux from the cell for LSC and cell uptake with the anion exchange mechanism [35]. A proportion of both cellular uptake and efflux of lithium can be attributed to passive diffusion. 

Approximate selectivity coefficients for the exchange of various cations for lithium ions on a sulphonated polystyrene, a typically strong acid resin, are given in Table 18.1. The values are relative to Li = 1.0. The selectivity coefficient between two ions is the ratio of their selectivities relative to lithium. Hence, for a sodium-hydrogen exchange ... 

Chromene[4,3-c]pyrazoles 34 are synthesized from l-(benzyloxy)-5-(2-fluorophenyl)-4-iodo-l//-pyrazole by iodine-lithium exchange using -BuLi, followed by addition of an aldehyde. Ring closure of the resulting lithium alkoxides, via an S Ar reaction, is effected using sodium hydride in THF under reflux (Scheme 11) <2001JOC4214>. 

As shown in Table 16.1, sodium, lithium, and hydrogen are the logical choices for the exchangeable ions. In practice, however, sodium and hydrogen are the ions of choice. The cation exchange resin using sodium may be represented by (/ "),(Na ), . Its exchange reaction with Ca and similar cations is shown below ... 

Sodium-lithium countertransport, anion exchange, and the leak mechanism are the most important transport routes for lithium in vivo. Lithium appears to substitute for sodium in all of these pathways in the erythrocytes (131) and also in the squid axon membrane (132). Sodium-lithium countertransport has been claimed to be abnormal in patients suffering from essential hypertension and in their close relatives (133). However, despite a decade of experimental study by many different laboratories, there is no consensus with regard to the true basis of the membrane defect, if indeed it is really present. Nor is it clear under what precise conditions the abnormality is manifest (134). 

PREPARATIVE TECHNIQUES Synthesized by step-growth polymerization between butylene glycol and terephthalic acid. PBT is often synthesized by ester-exchange polymerization using weak basic catalysts such as alkanoates, hydrides, and alkoxides of sodium, lithium, zinc, calcium, magnesium, titanium, etc. PBT is formed by the reaction of dimethyl terephthalate with l,4-butanediol at 0.020 atm and 160-230°C. Final reaction occur at 260-300°C under vacuum at 0.001 atm. 

A Parham cyclization strategy has been used to synthesize a wide variety of isoquinolines. For example, iodide 66 is smoothly converted to 67, which can be reduced (sodium borohydride/trifluoroacetic acid, 99%) or treated with nucleophiles and a Lewis acid to effect a-amidoalkylation. Likewise, imidazo[4,3-a]isoquinolinones (68), ° thiazolo[4,3-a]isoquinolinones (69), ° pyrrolo[2,l-a]isoquinolines (70), pyrrolo[ 1,2-6] isoquinolines (71), pyrrolo[l,2-6]acridinones (72), ° pyirolo[l,2-g]quinolones (73), ° thieno[3,2-y]indolizinones (74), ° and furo[3,2-/lindolizinones (75). ° It should be noted that the latter ring system 63 was prepared by deprotonation (LDA) rather than halogen-lithium exchange. °... 

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