Imine anion synthesis

Ornithine decarboxylase is a pyridoxal dependent enzyme. In its catalytic cycle, it normally converts ornithine (7) to putrisine by decarboxylation. If it starts the process with eflornithine instead, the key imine anion (11) produced by decarboxylation can either alkylate the enzyme directly by displacement of either fluorine atom or it can eject a fluorine atom to produce viny-logue 12 which can alkylate the enzyme by conjugate addidon. In either case, 13 results in which the active site of the enzyme is alkylated and unable to continue processing substrate. The net result is a downturn in the synthesis of cellular polyamine production and a decrease in growth rate. Eflornithine is described as being useful in the treatment of benign prostatic hyperplasia, as an antiprotozoal or an antineoplastic substance [3,4]. 

The same authors reported the synthesis of 6-substituted phenanthridines 360 via intramolecular trapping of imine anions 359179b. They speculated that these two observations could lead to the pentacyclic systems 361a-c from 358a-c via the cascade process indicated in Scheme 109. They also reported that compounds 358 could be converted into pentacyclic 13-azadibenzo[a, [Pg.130]

Evans and Domeier189,438 have described a general method for the synthesis of a variety of cyclic enamines from imine anions. An imine was added to a cooled ( — 30 °C) solution of lithium diisopropylamide in THF and, after 15 min, l-chloro-2-iodoethane (or l-chloro-3-iodopropane) was added in one portion (equation 28). This method was used by Bruno and coworkers439. 

Aldehydes and ketones are useM building blocks in organic synthesis. The direct a-C-H substitutions of carbonyl compounds are well known. However, selective P-C(sp )-H functionalization remains rare. The MacMillan group introduced Site activation model by dual aminocatalysis and photocatalysis, opening up a practical synthetic route to P-substituted aldehydes and ketones (Scheme 3.25). With this novel strategy, radical-radical coupling of enaminyl radical with electron-poor cyanobenzene radical anion can elegantly produce P-aiylated aldehydes and ketones [74]. A recombination of enaminyl radical with imine anion radical was also developed [75]. In the presence of Michael acceptors, radical addition of enaminyl radical to electron-deficient alkenes affords P-alkylated aldehydes [76]. 

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