2-Nitro- -imin

Alkylation of a-nitro keto imines. The key step in a conversion of cyclic a-nitro ketones to cyclic 3-substituted 1-nitroalkenes (4) involves alkylation of the dianion of an a-nitro imine (2) or hydrazone. The dianions are easily generated,... 

Aziridin l-Isopropyl-2-isopropylimi-no-3-methoxycarbonyl- El6b, 20 (Carbodiimid + R—CHN2) Bicyclo 2.2.1 heptan 2-Nitramino-l,3,3-trimethyl- Elba, 1153 (N-Nitro-imin-Red.) 2-Nitramino-l, 7,7-trimethyl- E16a, 1153 (N-Nitro-imin-Red.) Carhamidsiiure N-(Dimethylami-no-methylen)- -cyclohexyl-ester E4, 226... 

A few other A-substituted imines have occasionally been reduced to amine derivatives. Thus, A(-nitro imines (nitrimines) are reduced by NaBH4/dioxane %tOH/AcOH to A -nitroamines (Table 16, entry 14), and nitronate salts are reduced by BH3/THF to hydroxylamines (entry 15) via oximes. Isocyanates are reduced by LiBHEts, LiAlH(OBu )3 (at low temperature), or PhsSnH to formamides, which may be hydrolyzed in acidic workup to amines,while reduction with LAH affords A/-methylamines. ... 

Cyclizations of a nitro-imine and a nitro-guanidine are also described in this chapter. 

The structural unit of this subtype of polycyclic alkaloid is a 3-alkyl substituted pyridine, where remote terminal oxime, amine, methoxy amine, nitro, imine oxide or methoxy-oxime fuctionalities are characteristic in the monomeric forms. Polymeric pyridinium salts attached to a long linear carbonated chain through positions 1 and 3 are a substructural feature in a second subgroup of alkaloids. Related reduced dihydropyridinium salts have also been known since the discovery of haliclamine A and B. (See Tables 5 and 6 for C-NMR data). 

Kaupp and Toda performed soUd-sohd reactions by grinding together equimolar amounts of anilines and aldehydes in a mortar and keeping the mixture at room temperature for several hours or days. For instance, for quantitative conversion chloro imine required 120h, while methoxy/nitro imine needed 24h at 50°C (Scheme 3.7) [9], The rate of reaction considerably increased when these reactions are performed in ball mills. Thus, chloro and methoxy/nitro imines 36a-c can be quantitatively obtained in less than 30 min at room temperature when stoichiometric mixtures of the starting materials are ball milled. Larger runs could be performed in ball mills under heat control. 

Acid Dyes. These water-soluble anionic dyes ate appHed to nylon, wool, sUk, and modified acryHcs. They ate also used to some extent for paper, leather, food, and cosmetics. The original members of this class aU had one or mote sulfonic or catboxyHc acid groups in thein molecules. This characteristic probably gave the class its name. Chemically, the acid dyes consist of azo (including preformed metal complexes), anthraquiaone, and ttiaryHnethane compounds with a few azHie, xanthene, ketone imine, nitro, nitroso, and quHiophthalone compounds. 

A somewhat more complex application of this notion is represented by the CNS stimulant fencamfine (83). Diels-Alder addition of cyclopentadiene and nitrostyrene affords the norbomene derivative, 80. Catalytic hydrogenation reduces both the remaining double bond and the nitro group (81). ° Condensation with acetaldehyde gives the corresponding imine (82) a second reduction step completes the synthesis of fencamfine (83). ... 

After reduction of the nitro function of the porphyrin, the porphyrinamine intermediate can be reacted with z./l-unsaturated carbonyl compounds to yield porphyrins with a fused pyridine ring, which is formed by Michael addition, imine formation and dehydrogenation. 

Die Reduktion von prim, und sek. aliphatischen Nitro-Verbindungen mit waBriger Va-nadin(II)-chlorid-Losung in Dimethylformamid/Salzsaure bei pH<0 liefert Imine, die bei pH = 4 zu Carbonyl-Verbindungen hydrolysiert werden1 z. B. ... 

Aliphatische Nitro-Verbindungen gehenmit Chrom(II)-Salzenz. Tl. in Amine iiber. In einigen Fallen werden Imine und Oxime gebildet, die unter den Reaktionsbedingungen z. Tl. sofort in die Oxo-Verbindungen hydrolysieren. 

Auch primare und sekundare Nitro-alkane werden durch Chrom(II)-chlorid iiber die Imine in die entsprechenden Carbonyl-Verbindungen umgewandelt1 ... 

Methoxy- -oxim 379 4-Methoxy-phenyl- 631 -O-methyl-oxim 378 2-Nitro- 311 4-Nitro- 285, 765 -oxim 374, 502. 613 -phenylimin 609 -2-phenyl-propyl-(2)-imin 609 4-Phenylthio- 673 2-Thiocyanat- 635 m,ft),o)-Trifluor- 543... 

The condensation of nitro compounds and imines, the so-called aza-Henry or nitro-Mannich reaction, has recently emerged as a powerful tool for the enantioselective synthesis of 1,2-diamines through the intermediate /3-amino nitro compounds. The method is based on the addition of a nitronate ion (a-nitro carbanion), generated from nitroalkanes, to an imine. The addition of a nitronate ion to an imine is thermodynamically disfavored, so that the presence of a protic species or a Lewis acid is required, to activate the imine and/or to quench the adduct. The acidic medium is compatible with the existence of the nitronate anion, as acetic acid and nitromethane have comparable acidities. Moreover, the products are often unstable, either for the reversibility of the addition or for the possible /3-elimination of the nitro group, and the crude products are generally reduced, avoiding purification to give the desired 1,2-diamines. Hence, the nitronate ion is an equivalent of an a-amino carbanion. 

Reactions of nitro compounds with chiral imines have only recently been described. Either chiral 1-phenylethylamine (auxiliary) or the glyceraldehyde acetonide aldehyde was used as the chiral precursors of the imines 66 and 68, which reacted with 3-mesyloxynitropropane to give the 3-nitropyrrolidines dl)-67 and 69, respectively, with good diastereoselectivity. In fact, both products were obtained (almost) exclusively as trans diastereomers with high level of asymmetric induction, but the configurations of the newly formed stereocenters were not determined [44] (Scheme 13). N-Boc imines can be formed... 

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