Of cyclic amines

Formation and transformations of cyclic amines and lactams 98JCS(P1)2959, 99JCS(P1)2209. 

For aliphatic monoamine [43], it is shown that secondary amines R2NH always possess a higher promoting effect for the polymerization of AAM and even the primary amine PA will enhance the polymerization with Rr = 1.47 and Ea = 36.4 kJ/mol, while the tertiary aliphatic amine TPA will not provide the polymerization due to some steric hindrance (Table 6). All of the data of cyclic amines listed in Table 7 are effective, i.e., NMMP with Rr = 1.81 and Ea = 29.9 kJ/mol showing the absence of steric hindrance. 

Table 14.3. Preparation of cyclic amines from alkenyl thioacetals. ...

Michael-type addition of cyclic amines (piperidine, A-methylpiperazine) to thiazolo[3,2-A][l,2,4]triazole-5(6//)-ones 46 provides an easy entry to 2-aryl(alkyl)-6-(a-aminoarylmethyl)thiazolo[3,2- ][l,2,4]triazol-6(5//)-ones 207 (Equation 19) <1999AF1006, 2001AF470>. 

In an another analogous set of reactions, Matsumura and coworkers have shown that electrochemically derived A -acyliminium ions can serve as electrophiles in asymmetric alkylation reactions (Scheme 25) [57]. In this case, the methoxycarbamate of a series of cyclic amines was oxidized in order to generate the AZ-a-methoxy carbamates. 

The lactam formation from the oxidation of cyclic amines (353, for example) probably proceeds via intermediate 364. The nitrogen-iodine bond dissociates to give imine 365, which reacts again with a second equivalent of iodosobenzene to give another intermediate 366. Finally, 366 on reductive... 

The reaction of cyclic amines with FCIO3 is similar to that of FCIO3 with NHs (see above). For example, the following reaction takes place with piperidine (110) ... 

This work has since been extended to cyclobutyl isoxazolidine adducts (e.g., 86) from the cycloaddition of 87 to methylenecyclopropane (88) (Scheme 1.18) (124— 127). Thermolysis afforded a mixture of products, of which the bicyclic azepinone (89) predominated. Spirocyclic adducts were also prepared from an intramolecular reaction in the synthesis of cyclic amines (Scheme 1.72, Section 1.11.3). 

Ammonium ylides undergo [l,2]-shift in a manner similar to oxonium and sulfonium ylides. A preferentially migrating group is usually a benzyl group. A sequence of intramolecular formation of ammonium ylide and subsequent rearrangement was extensively explored by West and co-workers in the synthesis of cyclic amines. ... 

Much attention has been focused on the N-acyl derivatives of cyclic amines in view of the fact that this class of compounds includes several derivatives of biological interest. The most important example is given by proline, a... 

Mercuric Acetate Dehydrogenation of Cyclic Amines to Cyclic Enamines... 

However, if there is a lower enetgy decomposition pathway available, then an alternative degradation reaction dominates. There is a growing body of evidence to suggest that cydization reactions to form small stable ring compounds are one such decomposition pathway, especially for polyamides containing monomers with four to six carbon atoms (77,78) (eq. 7). The first example of this is the formation of cyclic amines, which is the principal decomposition pathway in nylon-4,6 (in eq. 7, n = 1 and R = H) (79) this has also been observed in MPMD-containing polyamides (in eq. 7, n = 2,... 

Unsymmetrical secondary and tertiary amines. Unsymmetrical amines are obtained in 50-95% yield by reaction of an alcohol and amine in the presence of this ruthenium catalyst. The intramolecular version of this reaction provides an efficient synthesis of cyclic amines either from oc,a>-amino alcohols and an alcohol or from a,tu-diols and an amine. The cyclization is useful for preparation of tetrahydroiso-quinolines.3... 

The synthetic method may be seen to be complementary to direct nucleophilic displacement. Whereas amines often react relatively sluggishly in metal-mediated nucleophilic displacements, they usually undergo facile reaction with carbonyls to form imines. The reduction of the imines (free or co-ordinated) may then be achieved by reduction with Na[BH4] or (less conveniently) by direct hydrogenation. This provides a very convenient method for the preparation of cyclic amines (Fig. 6-14). 

Shvo, Y. Kaufman, E. D. Configurational and conformational analysis of cyclic amine oxides. Tetrahedron 1972, 28, 573—580. 

The reaction principle was also extended to N-acyl derivatives of cyclic amines by Hoechst 261 262> ... 

The chemistry of ammonium ylides formed from the reaction of cyclic amines with carbenes was found to be dependent on the ring size of the amine.52 For example, treatment of 1-benzylazetidine (104) with ethyl diazoacetate in the presence of a copper (II) catalyst afforded pyrrolidine 106 in 96% yield. This result is consistent with ammonium ylide formation followed by ring expansion. In contrast, treatment of 1 -phenethylaz-iridine (107) under identical conditions gave the fragmentation product 109 in quantitative yield. Similar results were observed for the reaction of aziridine 107 with dichlorocarbene.53 On the other hand, reaction of 1-phenethylpyrrolidine with ethyl diazoacetate in the presence of a... 

We certainly do not intend these rules to restrict future research, but only to encompass a large amount of past experience with platinum(II) complexes. Obviously exceptions will, and have already, occurred. For example, the high activity of bidentate leaving groups such as oxalate and malo-nate (see structures of Fig. 4) first synthesized by M. Cleare and J. Hoe-schele in this laboratory are not encompassed nor is the effect of cyclic amines, developed by Tobe, which decrease the solubility of the complexes, but markedly enhance the antitumor activity. Here, studies of the rela-... 

A variety of cyclic amine products can be obtained by adding an electrophile to the organolithium intermediate resulting from the anionic cyclization, as is shown in Scheme 79154. The authors reported that the yields of the substituted products were modest to good, but the yields could be increased by using a V-benzylated 2-tributylstannyl-4-allylpyrrolidine, 252, which by transmetalation gives 253. 

This chapter does not cover cyclic amides and peptides, since their number would enormously expand this text. They are reviewed only if they serve as reaction intermediates during synthesis of cyclic amines. In addition, metal ions complexation will be presented in required minimum, for example, if it serves for template formation during ring synthesis or as a main topic in some application. In this chapter, most of the sections deal with the literature data for all cycle types, except Section 14.11.6, which focuses mainly on chemistry of cyclen and cyclam and their analogs and derivatives. In Section 14.11.8, we give only a brief overview of the utilizations and provide a reader with reviews where more detailed information may be found. 

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