2-ethoxymethyl acetate

Ethoxymethyl acetate (Ethyl cellusolve acetate) 156 1.2 Widely used in the past, but now considered unsafe... 

The argument is based on the explicit assumption that for each mechanism, the activation parameters are uninfluenced by temperature. The authors feel this assumption to be permissible in view of the constancy of these parameters in the case of the acid hydrolysis of methoxymethyl acetate and ethoxymethyl acetate. The plausibility of this assumption will be discussed in the next section. 

Acetic acid, [(ethoxymethyl)(2-ethyl-6-methylphenyl)amino]oxo-, sodium salt, should be >95% pure (EMA-producing oxanilic acid metabolite, referred to from this point as Metabolite I)... 

Acetic acid, [(ethoxymethyl) [2-( 1 -hydroxyethy 1 )-6-methy Ipheny 1] amino] oxo-,... 

Chloromethylation occurred in high yield at C-3 and C-4 when thienothiophene (73) was treated with paraformaldehyde and HC1 at 50 °C, to give chloromethyl derivative (96 Scheme 28). Treatment of the chloromethyl compound (96) with sodium acetate or sodium ethoxide gave the corresponding acetoxymethyl or ethoxymethyl derivatives (97). Analogous reaction with primary amines led only to the formation of bis-aminoalkyl compounds (98) and no peri-annelated products (99) could be detected (Scheme 29) <76AHC(19)123>. 

For (313), he began with the intact nucleoside 5-ethoxymethyl-2 -deoxyuridine (307) [160], After protection of the 3 - and 5 -hydroxy groups with p-chlorobenzoyl chloride, the resulting diester (308) was converted into a separable mixture of (309) (major) and (310) (minor). Alkylation of (35) with crude (309) gave (311) together with small amounts of unreacted (35) and a product tentatively identified as (310). Cleavage of the p-chlorobenzoates with methanolic sodium methoxide with concomitant transesterification yielded (312), which was saponified and then treated with barium acetate to afford the barium salt of (313). 

Fluoride-induced -elimination of p-(trimethylsily )ethyl ethers, which is the cornerstone of the 2-(trtmethylsilyl)ethoxymethyl (SEM) protecting group for hydroxyl functions (see section 4.4.5), has been modified for use in deprotecting cyclic acetals. For example, 4-(trimethylsilyl)methyM,3-dioxolanes46 and 5-tri-methylsilyl-13-dioxanes47 cleave on heating with lithium tetrafluoroborate [Scheme 2.16], The method works well for unhindered aldehydes and ketones. 

Acetal esters such as methoxymethyl (Mom),P9 (2-methoxyethoxy)methyl (Mem),t l benzyloxymethyl (Bom),P l tetrahydropyranyl,P l 2-(trimethylsilyl)ethoxymethyl (SEM)t l and (methylsulfanyl)methyl (hltm) are sensitive to noild aqueous acids in THE as well as to mild Lewis acids such as magnesium bromide in diethyl ether (2 equiv, rt, l-24h).t l In addition. Bom esters may be cleaved by catalytic hydrogenation.P l In the absence of acid, acetal esters display reactivities typical for unhindered alkyl esters. Surprisingly, these esters... 

For the liberation of acetal-masked alcohols under nonacidic conditions, p-eliminations, already mentioned in Section 3.1.2.1, were adopted. Following this concept the 2,2,2-trichloroethoxymethyl (35) and the 2-(trimethylsilyl)ethoxymethyl (SEM) ethers (36) were proposed. Both are introduced via Williamson syntheses and their removal is initiated by treatment with Zn or Zn/Cu in methanol or by fluoride-induced P-elimination respectively. Similarly, the trichloroethyl ether had already been applied in carbohydrate chemistry (Scheme 26). ... 

The aforementioned l,4-bis(2-hydroxyhexafluoroisopropyl)cyclohexane has been combined with the 2-trifluorometylacrylic structure [290,305,307]. The fluorodiol was half-protected with an ethoxymethyl group and reacted with 2-trifluoromethylacryloyl chloride in the presence of triethylamine to afford 2-[4-(2,2,2-trifluoro-l-ethoxymethoxy-l-trifluoromethylethyl)cyclo-hexane]hexafluoroisopropyl 2-trifluoromethylacrylate. This heavily fluorinated acrylate was copolymerized with 2-methyladamanty 2-trifluoromethylacrylate by anionic initiation with potassium acetate/18-crown-6 [307] as described in the literature [303] (Fig. 90). The copolymer (made from a 1 1 feed) was unexpectedly transparent with OD157 of 1.6/pm. However, imaging of the copolymer resists was sluggish perhaps due to their low Tg. Radical copolymerization was also performed with norbornene derivatives [290,305]. 

In contrast to the reaction of many 3-aminopyridazines with DMAD and acetylenemono-carboxylates, to give pyrimido[l,2-Z>]pyridazin-2(2//)-ones (see e.g., <83H(20)2225 , 6-amino-3(2//)-pyridazinone reacts by a Michael-type addition to give the aminobutenedioate (Scheme 58), which can be cyclized in acetic acid to the isomeric pyrimido[2,l-f)]pyridazin-4(47/)-one system. Condensation of 3-aminopyridazines and 6-amino-3(2//)-pyridazinones with diethyl ethoxymethyl-enemalonate proceeds in the expected Michael fashion to give aminomethylenemalonates which can be cyclized thermally <88JHC1535>. 

H-Pyrrole-1-acetic acid, 2-(ethoxymethyl)-5-formyl- 4249, 4573a ... 

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