Methoxy-methyl groups

Abstraction of H2+ from 3-methylanisole, generated in a flowing afterglow triple quadrupole apparatus, gives the radical anion (18). This species undergoes electron transfer to F2 followed by attack of fluoride ion at the methoxy methyl group to give the distonic carbene ion Carbene (19) displays reactivity characteristic... 

Figure 6.14 Disorder of the methoxy-methyl groups giving rise to...

Methyl radical loss from [3-methylbenzofuran]t gives a minor peak at m/e 77. In contrast, expulsion of a methyl radical from the [M-CO]t ion derived from 7-methoxy-4-methyl-coumarin is facile. Deuterium labelling experiments confirmed that the methoxy methyl group is preferentially eliminated (66JCS(C)1712). 

Aspects of the structures of these three polymorphs are shown in the following figures. Figure 16 shows the molecular structure of the trimer in the hexagonal polymorph and the flip disorder that results from the two positions for the methoxy methyl groups with 0.5 fractional occupancy for each group in the two alternate locations. This disorder results from a flipping of... 

Approach by RS to the carbonyl carbon of the ester group of 52 is restricted, whereas approach to the methoxy methyl group is open. Reaction to give 53 proceeds via a mechanism that is either described as SN2. 

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

Confirmation of the Identities of Metabolites and F by IH-NMR. Metabolites E and F of semduramicin were isolated in sufficient quantity to obtain IH-NMR spectra and to characterize structural changes based on observed differences with the parent structure. Although the most intense signals were from "experimental background , the spectral intensity of the two methoxy methyl groups was sufficiently clear to permit unambiguous assignment. 

In these examples the base name of the benzene derivative determines the carbon at which numbering begins anisole has its methoxy group at C 1 toluene its methyl group... 

The synthesis (60) and potent antitussive activity (61) of dimemorfan [36309-01-0] (41), D-3-methyl-/V-methylmorphinan, have been reported. This compound, prepared by a modification of the Grewe process, differs from dextromethorphan only by having a methyl group, rather than a methoxy group, in the 3 position. 

Pyridazine 1-oxides substituted at position 3 or positions 3 and 6 afford the corresponding 5-nitro derivatives. A methyl group at position 6 (a with respect to the iV-oxide group) is frequently converted into the cyano group, and a methoxy group at position 6 is demethy-lated by benzoyl chloride/silver nitrate. For example, 3-substituted 6-methylpyridazine 1-oxides give the 5-nitro derivatives (96) and the 6-cyano-5-nitro derivatives (97), whereas... 

Chloro-4-methyl- and 6-methoxy-4-methyl-pyridazine 1-oxides give the corresponding 4-acetoxymethyl derivatives, while the corresponding 6-substituted 5-methylpyridazine 1-oxides do not react at the methyl group. 

When alkoxypyridazine 1-oxides are heated alone or in the presence of p-toluenesulfonic acid the methyl group migrates from the methoxy group to the A-oxide group. In this manner, 4-methoxypyridazine 1-oxide rearranges to l-methoxypyridazin-4(l//)-one, 5-methoxypyridazine 1-oxide to 2-methylpyridazin-5(2//)-one 1-oxide and substituted 3,6-dimethoxypyridazine 1-oxides to l,3-dimethoxypyridazin-6(l//)-ones. 

Methyl-2,l-benzisoxazole and its 6-methoxy derivative are both readily brominated at the 3-methyl group with NBS (79TL4687, 74RTC139). The 4-methoxy isomer gives only the 7-bromo compound unless excess of the reagent is used, when 7-bromo-3-(bromomethyl)-2,l-benzisoxazole is obtained in 52% yield (74RTC139). However, there is... 

Other functional groups that are easily differentiated are cyanide (5c =110-120) from isocyanide (5c = 135- 150), thiocyanate (5c =110-120) from isothiocyanate (5c = 125 - 140), cyanate (5c = 105- 120) from isocyanate (5c = 120- 135) and aliphatic C atoms which are bonded to different heteroatoms or substituents (Table 2.2). Thus ether-methoxy generally appears between 5c = 55 and 62, ester-methoxy at 5c = 52 N-methyl generally lies between 5c = 30 and 45 and. S-methyl at about 5c = 25. However, methyl signals at 5c = 20 may also arise from methyl groups attached to C=X or C=C double bonds, e.g. as in acetyl, C//j-CO-. 

The empirical formula contains five double-bond equivalents. In the H NMR spectrum a doublet signal at Sh = 9.55 stands out. This chemical shift value would fit an aldehyde flinction. Since the only oxygen atom in the empirical formula is thus assigned a place, the methyl signal at Sh = 3.80 does not belong to a methoxy group, but rather to an /f-methyl group. 

The orientation of the HCH3 group, whether syn or anti to the methoxyearbonyl funetion, is shown by the NOE differenee speetrum in tetradeuteriomethanol. If the A/-methyl proton (<5/ = 2.92) is deeoupled an NOE effeet is observed for the protons at = 4.27, 4.07 and between 3 = 2.44 and 2.51 but not merely at 2.44. Thus, in tetradeuteriomethanol the A-methyl group is positioned anti to the methoxy earbonyl group. Henee the assignment of the endo and exo protons on C-6 and C-7 in the strueture M of eoeaine hydroehloride ean also be established. 

The largest shifts in frequency occur for methyl acetate, where the hydrogens in formaldehyde are replaced by a methyl group and a methoxy group, and most strikingly in acetyl chloride, where the hydrogen atom is replaced by a chlorine atom and a methyl group. 

The pyrimidine compounds are known to undergo a rearrangement of the 0-alkyl derivatives to the iV-alkyl ones. The methoxy derivatives of 1,3,5-triazine display a similar behavior. On applying methyl iodide to 2,4-dimethoxy-l,3,5-triazine one of the methyl groups is shifted giving rise to l-methyl-4-methoxy-derivative (22). This compound was also obtained by methylation of 4-methoxy-2-oxo-1,2-dihydro-1,3,5-triazine (18) with diazomethane. At higher temperature (100°C) in presence of methyl iodide a shift of both methyl groups takes place and methiodide is formed simultaneously (23). Similarly,... 

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