Methoxymethyl group

Displacement of a volatile with a nonvolatile alcohol is an important reaction for curing paint films with amino cross-linkers and amino resias on textile fabrics or paper. FoUowiag is an example of a methoxymethyl group on an amino resia reacting with a hydroxyl group of a polymer chain. 

A 3-acetoxypropyl group was used to protect an aziridine — NH group during the synthesis of mitomycins A and C acetyl, benzoyl, ethoxycarbonyl, and methoxymethyl groups were unsatisfactory. ... 

Meyers has demonstrated that chiral oxazolines derived from valine or rert-leucine are also effective auxiliaries for asymmetric additions to naphthalene. These chiral oxazolines (39 and 40) are more readily available than the methoxymethyl substituted compounds (3) described above but provide comparable yields and stereoselectivities in the tandem alkylation reactions. For example, addition of -butyllithium to naphthyl oxazoline 39 followed by treatment of the resulting anion with iodomethane afforded 41 in 99% yield as a 99 1 mixture of diastereomers. The identical transformation of valine derived substrate 40 led to a 97% yield of 42 with 94% de. As described above, sequential treatment of the oxazoline products 41 and 42 with MeOTf, NaBKi and aqueous oxalic acid afforded aldehydes 43 in > 98% ee and 90% ee, respectively. These experiments demonstrate that a chelating (methoxymethyl) group is not necessary for reactions to proceed with high asymmetric induction. 

Methoxymethyl group of perhydro[l,2]oxazino[3,2-7]quinolin-6-one 21 (R = MOM) was converted to a hydroxymethyl group by treatment with a boiling mixture of cone. HCl and MeOH, and the hydroxymethyl group was benzylated with PhCH Br in the presence of NaH and BU4NI in DMF at room temperature (00JA4583). 

Recently, Aumann et al. reported that rhodium catalysts enhance the reactivity of 3-dialkylamino-substituted Fischer carbene complexes 72 to undergo insertion with enynes 73 and subsequent formation of 4-alkenyl-substituted 5-dialkylamino-2-ethoxycyclopentadienes 75 via the transmetallated carbene intermediate 74 (Scheme 15, Table 2) [73]. It is not obvious whether this transformation is also applicable to complexes of type 72 with substituents other than phenyl in the 3-position. One alkyne 73, with a methoxymethyl group instead of the alkenyl or phenyl, i.e., propargyl methyl ether, was also successfully applied [73]. 

As mentioned above, methyl loss from ionized methoxymethyl derivatives of methyl benzoate is not restricted to the ortho-isomet 93. 2H labelling has shown that the mita and para compounds 96 also eliminate CH3 specifically from the methoxymethyl group. Interestingly, neither from the unsubstituted benzyl methyl ether 97 (X = H) nor from the X-substituted analogues 97 (X = CH2OH, NQ2) loss of CH3 is observed (21). Thus, the earbomethoxy function seems to play a decisive role in the dissociation process. 

These isomers resulted from the non-stereoselectivity of the initial coupling process typical of the aza-ACE reactions of the 7-isopropylidene-bridged dipolarophile 38, while molecular weight measurements and the presence of an isopropenyl group in the H NMR of each product supported C,A-methano-bridge formation. Such products were considered to arise via the bond reorganisation depicted by the arrows in adduct 156 in which one of the isopropylidene rc-bonds acted as the nucleophile to attack the methylene carbon of the adjacent A-methoxymethyl group. 

N-alkylation and N-acylation of piperazine-2,5-diones are quite common and have been routinely employed in several synthetic sequences (see Section IV,C). Such operations have also been performed as measures for the temporary protection of the nitrogen during further synthetic maneuvers in other parts of the molecule. Three different alkyl groups have been employed as such protecting groups. Kishi has used the methoxymethyl group for N-protection (potassium r-butoxide, chloro-methyl methyl ether 0°C, 75% yield). Deprotection was achieved by cone. HCl-ethanol at reflux temperature (81T2045). 

Hydroxymethyl anion equivalent (cf, 8, 495).2 This tin reagent undergoes transmetallation on treatment with LDA or BuLi at —78° to provide the corresponding lithium reagent (2) which adds to ketones to form a monoprotected derivative of a gem-diol. The methoxymethyl group of the adduct is cleaved on treatment with dilute acid. 

An acyl chloride was used in the synthesis of the spermidine alkaloid cannabisativine (162) by Natsume and coworkers [92]. As shown in Scheme 53, the precursor 160 was hydrolyzed with Ba(OH)2 and the resulting amino acid was directly converted to acyl chloride HCl salt, a cold solution of which was added dropwise to a potassium carbonate suspension in acetonitrile to achieve the lactam closure. Deprotection of the methoxymethyl groups with acid afforded macrolactam 161 in 43% yield from 160. 

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