REDUCTIVE AMINATION WITH

Morpholiaoglucopyranosides have beea syathesized from sucrose by selective lead tetraacetate oxidatioa of the fmctofuranosyl ring to a dialdehyde (6). This product was subjected to reductive amination with sodium borohydride and a primary amine such as benzylamine to produce the /V-henzy1morpho1ino derivative (7) (99). 

Reductive amination with pyridine bases 99UK61. 

Rather than preforming the a-amino ketimines to be reduced, it is often advantageous to form in situ the more reactive iminium ions from a-aminoketones and primary amines or ammonium salts in the presence of the reducing agent, e.g., sodium cyanoborohydride. Use of this procedure (reductive amination) with the enantiopure a-aminoketone 214 and benzylamine allowed the preparation of the syn diamines 215 with high yields and (almost) complete diastereoselectivities [100] (Scheme 32). Then, the primary diamines 216 were obtained by routine N-debenzylation. Similarly, the diamine 217 was prepared using ammonium acetate. In... 

Aromatic aldehydes can be reductively aminated with the combination Zn(BH4)2-ZnCl2,97 and the ZnCl2 assists in imine formation. 

Figure 7.11 Oxidation of glycoproteins with periodate, such as glycosylated antibodies, results in the formation of aldehyde groups that can be used for conjugation to dendrimers containing amine groups. Reductive amination with sodium cyanoborohydride results in coupling via secondary (or tertiary) amine bonds.

Gray, G.R. (1978) Antibodies to carbohydrates Preparation of antigens by coupling carbohydrates to proteins by reductive amination with cyanoborohydride. In Methods in Enzymology, (V. Ginsburg, ed.), Vol. 50, pp. 155-160. Academic Press, New York. 

For the solution-phase preparation of functionalized tropanylidenes, the authors simply dispensed solutions of the bromo N-H precursor in 1,2-dichloroethane (DCE) into a set of microwave vials, added the aldehydes (3 equivalents) and a solution of sodium triacetoxy borohydride in dimethylformamide (2 equivalents), and subjected the mixtures to microwave irradiation for 6 min at 120 °C. Quenching the reductive amination with water and subsequent concentration allowed a microwave-assisted Suzuki reaction (Section 6.1.2) to be performed directly on the crude products [295]. 

REDUCTION OF ALKYL HALIDES AND TOSYLATES WITH SODIUM CYANOBOROHYDRIDE IN HEXAMETHYL-PHOSPHORAMIDE (HMPA) A. 1-IODODECANE TO n—DECANE B. 1-DODECYL TOSYLATE TO n-DODECANE, 53, 107 REDUCTION OF KETONES BY USE OF TOSYLHYDRAZONE DERIVATIVES ANDROSTAN-17 0—OL, 52, 122 REDUCTIVE AMINATION WITH SO-... 

In the enzymatic part of the process, a one-pot conversion was achieved by using Candida lipase (Lip) to hydrolyze the ester and then LeuDH to catalyze the reductive amination (with or without N labeling). In this case, the coenzyme recycling was accomplished by adding FDH and formate. The same group used a similar enzymatic strategy to prepare labeled L-threonine and L-allothreonine starting from the a-keto methyl ester. ... 

In a multistep transformation between Gly and piperonal, the tetracyclic system ISO was prepared [92H(33)537]. During the studies of Securinenga alkaloids, ethyl 2-thienylacetoacetate was subjected to reductive amination with L-Pro-OMe after cyclization, two tetracyclic diastereoisomers 151 and 152 were formed (83JOC3428). 

REDUCTIVE AMINATION WITH SODIUM CYANOBOROHYDRIDE N,N-DIMETHYLCYCLOHEXYL-... 

In contrast, amino acid dehydrogenases comprise a well-known class of enzymes with industrial apphcations. An illustrative example is the Evonik (formerly Degussa) process for the synthesis of (S)-tert-leucine by reductive amination of trimethyl pyruvic acid (Scheme 6.12) [27]. The NADH cofactor is regenerated by coupling the reductive amination with FDH-catalyzed reduction of formate, which is added as the ammonium salt. 

The synthesis of valsartan (2) by Novartis/Ciba-Geigy chemists is highlighted in Scheme 9.5. Biphenylbenzyl bromide 18 is converted to biphenyl acetate 19 in the presence of sodium acetate in acetic acid. Hydrolysis of 19 followed by Swern oxidation delivered the biphenyl aldehyde 20, which underwent reductive amination with (L)-valine methyl ester (21) to give biphenyl amino acid 22. Acylation of 22 with penta-noyl chloride (23) afforded biphenyl nitrile 24, which is reacted with tributyltin azide to form the tetrazole followed by ester hydrolysis and acidihcation to provide valsartan (2). [See Biihlmayer et al. (1994, 1995).]... 

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