Nitromethane condensation

Ethanedial and nitromethane condense to yield l,4-dideoxy-l,4-dinitroinositols from which one of fourteen possible isomers was obtained due to low solubility in water31. 

SCHEME 27. Nitroseptanosides by nitromethane condensation with dialdehydo sugars. 

Since many nitrogen-containing organic compounds are explosive, some mention is appropriate here of possible hazards in working with nitromethane. Occasionally, some evidence of decomposition, in the form of mild evolution of heat and gases, has been observed by the author in concentrated, acidified aldose-nitromethane reaction residues from which the bulk of the nitroalcohols had been separated. Such residues usually have been either discarded at once or stored at —20° when further crystallization was anticipated. Generally, it may be stated that the aldose-nitromethane condensation reaction does not involve serious explosion hazards. 

Condensation reaction between active methyl and methylene compounds and S-alkylated thioureas provides another useful synthetic pathway to the 1,1-enediamines. Rajappa and coworkers20 reported that nitromethane condensed with S-methylated thioureas 72, prepared from the reaction of amines and methyl isothiocyanate followed by S-methylation, to form asymmetric nitro 1,1-enediamines 73 (Scheme 5). 

SCHEME 6.31 The nitromethane condensation can provide amine-substituted sugars and sugar precursors. 

This section presents some basic condensation reactions that result in the chain elongation of sugars. The examples presented here are historically important to the general field of carbohydrate chemistry, and include the cyanohydrin chain extension and the nitromethane condensation. 

Another very useful method for the formation of carbon-carbon bonds that also results in the chain extension of sugars is the nitromethane condensation. This reaction involves the addition of nitromethane to the reducing end of sugars under basic conditions. Subsequent treatment with... 

SCHEME 6.64 Nitromethane condensations are useful for the chain elongation of sugars. 

A typical synthetic approach based on the 1,4-addition of the phosphorus nucleophile to a sugar derived nitromethane condensation product is depicted in Scheme 9.21. 

Nitromethane condenses with suitable dialdehydes in an alkaline medium to give cyclic products in which the methyl groups of two nitromethane molecules are incorporated into a ring. Thus the reagent reacts with glyoxal to give a mixture of isomeric inositol derivatives, one of which (1) can be obtained in pure form due to... 

Condensation with carbonyl compounds. Nitromethane condenses with benz-aldehyde in methanol-aqueous sodium hydroxide at 10-15° to give a sodium enolate. 

Synthesis from myo-inositol Total syntheses of trehazolin (1) and its isomers have established both its structure and absolute configuration (Schemes 11-13). Thus, base-catalyzed nitromethane condensation of the dialdehyde generated by periodate oxidation of ( )-l,2-(9-cyclohexylidene-myo-inositol (74) gave a mixture of the nitro-diols, which was hydrogenated in the presence of Raney nickel, followed by acetylation to afford the three diastereoisomeric 2,3-(9-cyclohexylidene derivatives 75 (40%), ( )-76 (5%) and 77 (5%) of 5-acetamido-l,4-0-acetylcyclopentane-l,2,3,4-tetraol. The minor racemic mixture 76 was de-O-acetylated, N,0-isopropylidenated, and then resolved by... 

We shall not want to liberate (14) as it would cyclise. In any case, it is shorter to reduce CN in the same step as reduction of C=C and NO2 at the end. Experiments showed that it was better to do the nitromethane condensation in two steps. 

Nitromethane condensation with the dialdehyde obtained from periodate-oxidized uridine yields a crystalline 3-deoxy-3-nitro-g-D-glucopyranosyluracil contaminated by the D-galacto isomer their... 

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