Nitromethane in condensation with formaldehyde

Nitrogen, purification of, 41, 97 Nitromethane in condensation with formaldehyde, 41, 67 1-Nitro-l-methylcyclohexane, 43, 89... 

The reaction between formaldehyde and compounds containing acidic protons is probably the most important route to polyols. Some of these polyols have been 0-nitrated and used as practical explosives. The condensation of nitromethane and nitroethane with excess formaldehyde in the presence of potassium hydrogen carbonate yields tris(hydroxymethyl)nitromethane (58) and l,l-bis(hydroxymethyl)nitroethane (60) respectively. The nitration of (58) and (60) with either absolute nitric acid or mixed acid gives the secondary high explosives, (59) and (61) respectively. 

The Mannich condensation between nitromethane, formaldehyde and t-butylamine, followed by nitrolysis of the resulting product (101), has been used to synthesize 1,3,5-trinitro-hexahydropyrimidine (102) (TNHP) treatment of the latter with formaldehyde in a Henry type methylolation, followed by 0-nitration with nitric acid, yields the nitrate ester (103). ... 

Gronowitz found the Pictet-Spengler reaction a convenient route for the preparation of (259 equation 22) (70AK(32)217). Thiophene-3-carbaldehyde was condensed with nitromethane to give w-nitrovinylthiophene. Reduction of the nitro derivative with LAH afforded the /3-(thienyl)ethylamine. The condensation of this amine with formaldehyde to the corresponding imine followed by cyclization with hydrochloric acid proceeded very smoothly and in high yield. The aromatization was achieved with potassium ferricyanide in an alkaline dioxane-water mixture. 

NIBTN was first prepd by Hofwimmer(Refs 1 2) by condensation of 3 moles of formaldehyde with 1 mole nitromethane in the presence of KHCOj and subsequent nitration of the product. Modifications of this method are described in Refs 3,4,5,6,10 15. Aaronson(Ref 8) investigated the methods existing prior to-1941 and came to the conclusion that Stettbacher s method(Ref 5) was the best... 

This explosive was first described in 1912 by Hofwimmer118 who prepared it by the condensation of three molecules of formaldehyde with one of nitromethane in the presence of potassium bicarbonate, and by the subsequent nitration of the product. 

The condensation of nitromethane with formaldehyde is not typical of the general reaction since more than one molecule of formaldehyde tends to condense with one molecule of nitromethane even in the presence of a large excess of the latter. When equimolar quantities of formaldehyde and nitromethane are allowed to react the following approximate percentages of the three possible condensation products are obtained 1 ... 

The yields of nitro alcohols from simple nitroparaffins and aliphatic aldehydes or benzaldehyde are usually above 60%. The condensations are generally carried out with aqueous ethanolic sodium hydroxide, although weaker bases are sometimes desirable to prevent polymerization of the aldehyde. Sodium bisulfite addition compounds of the aldehydes are sometimes used. Better results are obtained with sodium methoxide than with alkali hydroxides in the condensation of nitroethane with formaldehyde. Sodium alkoxides are also used to effect the condensation of nitroethane with acetone and cyclohexanone. Condensation proceeds to the nitroalkanediol stage in certain cases with both nitromethane and with formaldehyde. ... 

The first selenium donor atoms incorporating sarcophaginate was obtained starting from the initial cobalt(III) NsSes-semiclathrochelate by condensation with nitromethane and formaldehyde in water (Reaction 37). 

Condensation of [Co(tacn)2] bis-triaminate with formaldehyde and nitromethane led to an unusual clathrochelate complex with a stable carbanion, A tripodal cap from three formaldehyde and one nitromethane species formed on one octahedral face as expected by the conventional route. However, on another octahedral face, the capping process proceeded in an unusual way to stabilize a carbanion chelate and to methylate the remaining coordinated amino group ... 

When 1,3-propanediamine semiclathrochelates have been used instead of ethylenediamine derivatives, the encapsulation of large metal ions in low oxidation states predominated. For instance, the rhodium(III) sarcophaginate was obtained by template condensation of the corresponding semiclathrochelate with formaldehyde and nitromethane in a high yield [5j ... 

Barger (80) starting from phenethyl alcohol, obtained phenethyl chloride, which, when heated with dimethylamine, yielded dimethyl-phen ethyl amine. By nitration, reduction, diazotization, etc. a base identical with natural hordenine was obtained. Rosenmund (81) condensed p-methoxybenzaldehyde with nitromethane and reduced the alkoxy nitrostyrene to p-methoxyphenethylamine. With methyliodide a mixture of bases was formed from which, after demethylation with boiling hydroiodic acid, hordenine was obtained in low yield. Voswinckel (82) treated p-methoxyphenacyl chloride with dimethylamine, then demethylated and reduced to hordenine. Ehrlich and Pistschimuka (83) started from tyrosol, p-0H-C6H4-CH2CH2OH, converted it to the chloride, which, with dimethylamine gave hordenine. Further synthesis have been elaborated by Spath and Sobel (84) and by Kindler (38). Raoul (67, 69) obtained hordenine in 50 % yield, by methylating tyramine with formaldehyde and formic acid. 

The template condensation of [Co( L869)2] + with formaldehyde and nitromethane in aqueous solution, followed by separation of the reaction mixture by ion-exchange chromatography, is represented in Schemes 4-7-4-9. Branched routes of successive transformations result in the formation of four main products, [Co(L872)]3+ to [Co(L875)] + [63, 64]. 

Interestingly, nitromethane (CH3NO2) undergoes aldol condensation with meth-anal (formaldehyde, H2CO) in the presence of base to produce the nitrotriol, 2-hydroxymethyl-2-nitro-l,3-propanediol (Problem 9.15). The process by which it forms is presumed to be analogous to that seen in the formation of pentaerythritol (2,2-dihydroxymethyl-l,3-propanediol), Scheme 9.44, from the reaction between ethanal (acetaldehyde, CH3CHO) and methanal (formaldehyde, H2CO). 

The 2-nitroethanol obtained by this procedure is quite satisfactory for synthetic purposes, such as the preparation of nitro-ethylene. The small amount of light petroleum ether dissolved in the 2-nitroethanol can easily be removed under reduced pressure. Most of the remaining diphenyl ether can be removed by one redistillation under vacuum, since the fore-run is relatively rich in diphenyl ether. The main fraction has n-u 1.4425-1.4431. Although vacuum redistillation of 2-nitroethanol which has been freed by the present procedure from higher condensation products of formaldehyde with nitromethane is relatively safe, it is recommended that the procedure be carried out behind a safety shield or a barricade. 

Nitroethanol prepared by the formaldehyde-nitromethane method should not be distilled without use of diphenyl ether as a heat-dispersing agent. The residue, consisting of di- and tri-condensation products of formaldehyde with nitromethane, when hot and concentrated, and particularly when the vacuum is broken and air is let in on the hot distillation residue, is very likely to undergo a flash detonation, or at least a fume-off which may proceed with explosive violence. Use of diphenyl ether is a wise safety precaution in the distillation of 2-nitroethanol made by other methods as well. 

One more product of the condensation of [Co(tame)2] with nitromethane and formaldehyde with a yield of ca 10% was identified in Ref 148 as macrotetracyclic [Co(NOtetrasartame)]Cl3 3H20 sarcophaginate 4. Its reduction with zinc dust in aqueous hydrochloric acid resulted in the corresponding cobalt(II) [Co(AMtetrasartame)] aminosarcophaginate, which can either oxidize to a cobalt(III) complex or demetallate with hydrochloric acid to cleave four-membered chelate fragments. Both macrotetracyclic cobalt(III) complexes are remarkably stable to hydrolysis in acidic (6 molar hydrochloric acid at 60°C) and mildly basic (pH < 9 at 25°C) conditions, although they decompose at pH >9. 

An in situ procedure involving condensation of the appropriate open-chain, spiro-linked amine with nitromethane and formaldehyde in water in the presence of copper perchlorate has been employed to obtain the dinuclear Cu(II) perchlorate complex of 44 (78). The visible spectrum of this complex is very similar to that of its mononuclear analogue. In solution, the metal in each complex was assigned a te-tragonally distorted octahedral environment in which axial solvation completes the coordination sphere. As with other complexes of this general type, the addition of dilute acid did not affect the spectrum of this species. 

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