2-Mercaptoethylamine derivs

Primary and secondary aliphatic and aromatic amines react readily with thiiranes to give 2-mercaptoethylamine derivatives (Scheme 76) (76RCR25, 66CRV297). The reaction fails or gives poor yields with amines which are sterically hindered e.g. N,iV-dicyclohexylamine) or whose nitrogen atom is weakly basic e.g. N,A/ -diphenylamine). Aromatic amines are less reactive and higher reaction temperatures are usually required for them. The reaction mechanism is Sn2 and substituted thiiranes are attacked preferentially at the least hindered... 

Figure 22.30 An iodoacetamide derivative of PE containing an extended spacer arm can be constructed through a carbodiimide coupling of iodoacetic acid to PE, followed by reaction with 2-mercaptoethylamine, and finally another reaction with iodoacetate.

The actual pathway by which fatty acid oxidation occurred was established by Lynen (1952-1953). Its unique and characteristic reaction was the thioclastic attack by coenzyme A on the B-ketoacyl CoA derivative, splitting off the 2C fragment, acetyl CoA. Free coenzyme A was very difficult to isolate and although it was synthesized in Todd s laboratory in Cambridge in the mid-1950s, much of the early work from Lynen s laboratory utilized A-acetyl cysteamine as a not very efficient (ca.1%) coenzyme A analogue. It carried the essential thiol group of the B-mercaptoethylamine end of CoA and could be used in most, but not all, of the steps in the spiral. 

The unsymmetrical nature of / -mercaptoethylamine should lead to geometric isomerism among its metal complexes, cis and trans isomers might be expected with the square planar nickel (II) and palladium (II) derivatives and facial and peripheral isomers with cobalt (III). However, during the course of the preparation of various samples in which the procedure and experimental conditions were varied, no evidence of such isomerism was apparent (6, 15). This is particularly evident in the case of the cobalt (III) complex, CoL3. Samples prepared by the addition of cobalt (II) chloride 6-hydrate to strongly basic aqueous solution of the ligand and by displacement of ammonia and (ethylenedinitrilo)-... 

The family of complexes containing Schiff base ligands derived from a-diketones and /J-mercaptoethylamine [the 2,2 -dialkyl (ethanediylidenedinitrilo) -diethanethiol complexes, structure V, Ni(BE), Ni(PE), and Ni(OE)] are well designed to extend chelate ring-forming ligand reactions to their ultimate by forming complete macrocycles, that completely enclose the metal ion. The objective is shown in Equation 24. 

The Hantzsch pyridine synthesis gives initially a dihydropyridine from the cyclization reaction. Adaptation of this reaction to the use of a 2-methylenethiazolidine yields the fused tetrahydro derivative (502) (77LA1888). Perhydro derivatives are simply prepared from 2-substituted thiazolidines by cycloalkylation as for (503) (80S387). The thiazolidine may also be generated in situ as in the reaction between y-benzoylbutyric acid and 2-mercaptoethylamines under azeotropic conditions to yield (504) (65JOC1506). 

The first Cr111 complexes with A)A ,-diphenyhh io u rea ([Cr(L9)3], characterized by X-ray crystallography),685 2-mercaptopyridine-A-oxide ([Cr(L10)3]),686 and 2-mercaptoethylamine (fac-,S -[Cr( L11 )3])687 have been described. The latter complex has been used for the synthesis of A -bridged heteropolynuclear compounds (Section 4.6.5.9.12). 87 The recent interest in the Cr111 complexes of thiosemicarbazide derivatives (such as [CrL12(acac)2]) is related to their potential antibacterial, antiviral, or antitumor activities.688-693... 

Amino thiol derivatives. In a series of N-monosubsti-tuted 2-mercaptoethylamines, the p-phenethyl derivative gave good protection to mice vs. 1000 r, and the p-2-thienylethyl derivative gave fair protections No protection was shown by N-monosubstituted derivatives containing thioureido groups and no protective activities were reported for N-monosubstituted Bunte salts of MEA carrying sulfone substituentsS ... 

The reactions of -mercaptoethylamine, L-cysteine, and D-penicillamine, and their derivatives, with a-haloketones represent an important synthetic route to dihydrothiazines. " For example, the methyl esters of L-cysteine and D-penicillamine reacted with 3-bromo-2-oxopropionic add... 

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