Aminomethyl derivatives bases

Oxidation of 8-hydroxymethyl-2-isopropyl-l 1 //-pyrido[2,l-b]quinazolin-11-one with pyridinium chlorochromate in methylene chloride gave the 8-carboxaldehyde, which was converted into its 8-aminomethyl derivatives by reacting with amines followed by reduction of the Schiff bases with sodium cyanoborohydride in acetic acid (87JOC2469). 

The 1-aminomethyl derivative of pyrimidine nucleoside 343 undergoes cyclization in the presence of a mixture of triethylamine and pyridine at 90 °C with concomitant demesylation to yield 344 but a variety of other bases and conditions failed to produce the required intramolecular nucleophilic attack <2006JOC299>. 

Deaminomethylation of Mannich bases may also occur in the presence of electrophilic species, capable of replacing the aminomethyl group linked to the substrate moiety, such as, for example, diazonium salts acting on Mannich bases of phenols and indoles, or alcohols acting on cyclic O-Mannich bases. The deaminomethylation reaction is also prc.sent in. several equilibria afforded by aminomethyl derivatives of benzotriazole (sec 209, Chap. 1, C.6). 

Steroidal aminomethyl derivatives have been subjected to some of the reactions typical of Mannich bases, described in Chap. II, usually with the aim of introducing structural modifications of the molecule by means, in particular, of deamination and hydrogen-olysis. The formation of a quaternary ammonium salt (mainly iodomethylatc) by N-alkylation of the base - is also performed to the same end in order to obtain unsaturated deaminated products. ... 

Photography—Several types of Mannich bases and derivatives are employed in this field. 599 Crosslinking agents derived from piperazine (534, Sec. A.2) are hardeners for gelatin photographic emulsions, and O-aminomethyl derivatives of piperazine, used under the form of polymeric quaternary ammonium salts 599, are useful as sensitizers for photographic emulsions. ... 

In the case where formaldehyde reacts initially with the amine (path a), a condensation product having the stmeture of X-aminomethyl derivative or methyicneimmonium salt is formed, which is then able to attack the substrate RH. Alternatively (path b), a hydroxymethyl derivative is generated, which gives the Mannich base by reaction with the amine. Thus, the main questions concerning the reaction mechanism arc... 

Less abundant examples of aminomethylation on ring B are reported in the literature most of them are connected with the synthesis of the vinylogous bases described in the following section, which deals with the reactions of steroid Mannich bases. Aminomethyl derivatives at ring C are unknown, and only a few cases of aminomethylation at the penta-atomic ring D arc reported. In 16-ketoandrostane a slight preference for attack at the less hindered position 15 is observed." ... 

The 5-aminomethyl derivatives of 4-aminotriazole owe their high strength as bases to the aliphatic amino group. The strongest bases in Table II are the 5-methylamidino derivatives 15, which have pX, values around 10, except where the presence of a free acidic group (NH) in the nucleus produces zwitterions of which the two pKs are reversed, as in glycine. 

The tetrakis-bromomethyl derivatives, apart from themselves being useful m-terphenyl base synthons for the construction of thia- and aza- cuppedophanes and cappedophanes (see Sects. 4.1 and 4.5), are also precursors to other useful molecular base synthons. Tetrakis-mercaptomethyl derivative 90 [9], tetrakis-aminomethyl derivatives 92 [11] and tetrakis-p-toluenesulfonylmethyl derivative 93 [11] are three new m-terphenyl templates easily accessed from 8 (Scheme 11). While the mercaptomethyl derivative was prepared via the isothiouronium salt 89, the tetrakis-aminomethyl derivatives 92 and 93 were prepared via the phthalimido derivative 91 [11]. 

Domination of the S-diastereomers for the dioxovanadium(V) Schiff base complexes being derivatives of aromatic orf/zo-hydroxyaldehydes or ketones and (S)-(+)-2-(aminomethyl)-pyrrolidine [35] was shown and the molar ratio of the diastereomers was determined by means of integration of the H signals.85... 

A modular and flexible approach to polythiophene sensors based on the polymerization of a thiophene-activated ester has been reported (Bernier et al. 2002). Subsequent reaction of the pol5mierized NHS ester with a variety of diamines permits the synthesis of sensors for different analytes from a common platform. For example, reaction of the NHS polymer with an aminomethyl-modified 15-crown-5 derivative yielded a polymer that underwent color changes in the presence of alkah cations (Fig. 12.14). 

Regioselective aminomethylation and subsequent cyclization of methyl 2,4-dihydroxybenzoate 517 was accomplished through a Mannich reaction with formaldehyde and primary amines in methanol to yield 3-substituted-3,4-dihydro-2/7-l,3-benzoxazine derivatives 518 (Equation 60). Simultaneous mixing of the reactants resulted in poor yields, but good yields were achieved by the pretreatment of paraformaldehye with a primary amine to form a Schiff base, followed by the addition of compound 517 <2001TL7273>. 

Hydroxypyridine reacts with formaldehyde and base to give the 2-hydroxymethyl derivative which reacts further, ultimately to yield the 2,6-disubstituted product. No 4-substitution is detected in this case or with 3-hydroxy-2,6-dimethylpyridine when it is treated under the same conditions (75RCR823). 3-Hydroxypyridine readily undergoes bis-aminomethylation at the 2- and 6-positions. 

A library of di- and trisubstituted 5-amino-l 77-1-benzazepine derivatives was assembled through attachment of a preformed 1-benzazepine unit to an aminomethylated polystyrene resin. The initial solution phase synthesis of the 1-benzazepine moiety was based on an intramolecular Dieckmann cyclization (type d) followed by a ketone to primary amino group transformation via reduction ( NaBH3CN) of an imine intermediate <2007JC0487>. 

---