A New NADH Model:Design, Synthesis And Research On Its Character

Nicotinamide adenine dinucleotide hydrogen (NAD(P)H) could play an important role in living systems and this has stimulated a great deal of interest in the fields of bioorganic and organic chemistry. It’s involved in transferring electrons during glycolysis, fatty acid metabolism, amino acid decomposition, citric acid metabolism, and photosynthesis in living systems. A large number of NAD(P)H model compounds have been designed and synthesized for studying stereoselective reduction and some other related bio-process. The unique ability of these compounds in steroselective reactions especially in the biological systems to reduce unsaturated groups (carbonyls, conjugated olefins, etc.) has stimulated a great deal of interests for the bionicist and organic chemist.Many NADH model compounds have been designed and synthesized, since chemist reported the first example of NADH and it’s asymmetric reduction reactions with that model compound. The review on coenzyme NADH model compounds was in1991by Davies and coworkers. In the15years, numerous new NADH models have been reported. Thus, a considerable portion of today’s efforts on NADH models is in fining the factors, principles and conditions of their stereoselective reduction reactions.Much work has been done to improve the stereoselectivity of the reduction with methyl mandelate by NADH. Generally speaking, chemists designed NADH models by three ways:the first one was to chang the substituent of dihydronicotinamide ring with a view to forming remote sterically-demanding side chain, inorder to that they wanted to control the stereos electivity of the reduction. The second one was to incorporate a substituent at the reaction center:the C4position of dihydropyridine ring. The third one was to design the specific conformation to obtain stereoselectivity.However, in the first situation dihydronicotinamide unit needs to be modified significantly by introducing big chiral auxiliaries, a complicated ring or changing the amide group into a chiral sulfinyl group. The second one suffered from loss of the chirality at C4position during the course of the model reductive reaction, at the same time, we cannot achieve the reuse of the cycle between NAD+and NADH. The third one was particular and by far few such models has been studied.Based upon above, a new type of NAD(P)H model compound with axial chirality was designed and synthesized by an efficient and convenient synthetic method, and it’s reducibility was researched, with high productivity and stereoselectivity. The structures of these model compounds were confirmed by1H-and13C-NMR and MS. In this article, the abnormal optical character of the NAD(P)H was determined with the principle discussed in depth.