Tertiary nitro groups

The anion of nitromethane is particularly reactive in S l reactions. Various kinds of tertiary nitro groups are replaced by a nitromethyl group on treatment with the anion of nitromethane (Section 7.1).49 2-Iodoadamantane reacts with the anion of nitromethane in the presence of acetone enolate (entrainment reaction) under irradiation of a 400-W UV lamp to give 2-ni-tromethyladamantane in 68% yield, (see Eq. 5.32).50a 1-Iodoadamantane also reacts with the anion of nitromethane in a similar way.50b... 

Clearly, the nitroalkene dipolarophile oxidoisoquinolinium betaine 123 is nonideal for the synthesis of the hetisine alkaloids, as mass throughput for the needed cycloadduct would be low, and conversion of the tertiary nitro group to carbon-based functionality, as would be required in the latter stages of the synthesis, could be problematic. On the other hand, an ene-nitrile dipolarophile has several potential advantages over nitroalkene dipolarophile. Most importantly, the ene-nitrile cycloadduct has carbon functionality installed at the C-10 position. Second, the conjugate addition byproduct pathway that occurs so readily for the nitroalkene oxidoisoquinolinium betaine 123 system (see Scheme 1.13) should be much slower... 

Reduction of t-nitro groups.1 NaBH4 in combination with Cu(OAc)2 reduces aryl and aliphatic tertiary nitro groups to amino groups in 75-80% yield. 

On the basis of their investigations of nearly 35 nitro compounds, Komblum, Ungnade and Smiley have distinguished the vibrations of primary, secondary and tertiary nitro groups in aliphatic nitro compounds (Table 23). 

The formation of the twelve-membered lactone, IX/52, from the eight-mem-bered ketone, IX/51, prepared by alkylation of the aldehyde, IX/50, can be explained as an enlargement of a medium-sized ring. The driving force is probably the resonance stabilisation of the secondary nitro group in base (nitro-nate), compared to the tertiary nitro group in the starting material (Scheme IX/9) [29],... 

Na2S-5H20 and sulfur (1 atom equiv.) in DMSO until the initial blue-green color turns to yellow. A tertiary nitro group is reduced by the reagent to the corresponding thiol and a polysulfide the latter compound is reduced to the thiol by aluminum... 

Slovetskii and co-workers according to [7] examined the frequencies of principal NO bands for primary, secondary and tertiary nitro groups (Table 18). 

Reactions of the replacement by hydrogen of the tertiary nitro group in aliphatic and alicyclic compounds were recently described by Kornblum and co-workers (145). They occur at room temperature when the nitro compounds are treated with the sodium salt of methyl mercaptan. 

Chatgilialoglu studied (MesSijsGeH as a new radical hydrogen donor, and found that reduction of chlorides, bromides, and iodides, deoxygenation of secondary alcohols via a thiono ester (Barton-McCombie reaction), deamination of primary amines via isocyanides, removal of PhSe group, and replacement of a tertiary nitro group by hydrogen were extremely effective (Scheme 11.15) [31]. 

Nitro alcohols of the type H0CH2-C(N02)R R" do undergo base-catalyzed cleavage ( demethylolation ), but here, the (tertiary) nitro group cannot compete in anionization. 

Reductions (Me,Si)3GeH is a novel reducing agent based on a mechanism involving radicals. It replaces carbon-bound halogen atoms, xanthate functions, isocyanides, phenylseleno, and tertiary nitro groups (10 examples, 96-100%). 

I ytko-Krasudca, Piotrowska and T. Urbanski (146) described the replacement by hydrogen of tertiary nitro group in 5-nitro-l,3-dioxane by acting with ethylene glycol in KOH at 120—140°C with yields of up to 60%. 

Transfer hydrogenation conditions have also been applied to the reduction of tertiary nitro groups (Scheme 40)J ... 

Phenylsulphonyl)nitromethane is C-alkylated preferentially by benzyl halides, primary alkyl iodides, and allylic acetates, the latter in the presence of catalytic tetrakis(triphenylphosphine)palladium, providing secondary a-nitrosul-phones (cf. Vol. 5, p. 197). The synthetic utility of this process, other than for the preparation of a-nitrosulphones themselves, has been enhanced by the development of efficient desulphonation processes, " thus providing an overall synthesis of nitroalkanes. Nitroalkanes are also the products of the replacement of tertiary nitro groups by nitromethyl via sodio nitromethane. ... 

---