Reactions of nitric oxide (NO) with amines in organic solvents
were studied using Hantzsch
dihydropyridines and aromatic primary amines as substrates.
Hantzsch dihydropyridines are
readily oxidized by nitric oxide to give the corresponding pyridines in
quantitative yields. The
addition of oxygen accelerates the reaction rate considerably. On
the other hand, aromatic primary
amines give deaminated products by the reaction with nitric oxide only
in the presence of oxygen
in ethereal solvents or chloroform.
[reaction: see text] 9-Tosyl-3,4-dihydro-beta-carboline (1) reacted with a ketone in the presence of (S)-proline as a catalyst to give the corresponding addition product in good yield and high enantioselectivity. In the process, a small amount of water was found to affect the stereoselectivity of the products. The system was applied to reaction of compound 1 and 3-buten-2-one to give 3,4,6,7,12,12b-hexahydro-1H-indolo[2,3-a]quinolizin-2-one, which is a versatile precursor for the synthesis of some indole alkaloids.
Monocyclic 1,2,3-triazines reacted with Grignard reagents to form adducts due to N-2 and C-5 attack together with p-su bstituted acrylaldehydes and N-substituted pyrazoles; the results show that the N-2, C-4, and C-5 positions are reactive towards Grignard reagents.
[reaction: see text] 9-Tosyl-3,4-dihydro-beta-carboline reacted with 3-ethyl-3-buten-2-one in the presence of (S)-proline to give (3R,12bR)-3-ethyl-12-tosyl-3,4,6,7,8,9,10,11,12,12b-decahydro-1H-indolo[2,3-a]quinolizin-2-one in complete enantio- and diastereoselectivity. The compound thus obtained was readily transformed to ent-dihydrocorynantheol in three steps.
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