4-acetyl-2-methoxymethyl

In a new route to a-keto esters, Zbiral and Werner701 acetylated methoxymethyl-enetriphenylphosphorane and oxidized the product with lead tetraacetate. 

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. ... 

On interruption of the reaction at the minimum point, only a low yield of the final product, 5-(methoxymethyl)-2-furaldehyde, could be isolated as the semicarbazone, but a crystalline phenylosazone (m.p. 120.5-121.5°, [< ]d —9° in chloroform) was obtained. It was not isolable at the end of the reaction. No osazone was obtainable from the hydroxy-glycal without prior, acid treatment. Analyses of the osazone indicated that it was a mono-O-methyl derivative of the parent CgHgCh. This is the same formula that was found by Bergmann and Zervas (see above ) for the parent of the phenylosazone obtained by direct treatment of 2,3,4,6-tetra-0-acetyl-(2-hydroxy-D-glucal) with phenylhydrazine. Whereas Bergmann and Zervas were unable to acetylate the compound further, Wolfrom, Wallace and Metcalf introduced an O-acetyl group into their mono-O-... 

Chemical Name 5-Thia-l-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid, 7-(((2Z)-(2-amino-4-thiazolyl)(methoxyimino)acetyl)amino)-3-(methoxymethyl)-8-oxo-, l-(((l-methylethoxy)carbonyl)oxy)ethyl ester, (6R,7R)-... 

To a solution of 37.4 g of 7-amino-3-methoxymethyl-3-cephem-4-carboxylic acid l-(isopropoxycarbonyloxy)ethyl ester in 689 ml ethyl acetate at 2-3°C is added for 25 min 0.105 moles Z-(2-formamidothiazol-4-yl)-methoxy-acetyl chloride hydrochloride. After 25 min pH is adjusted to ca. 6.5-7.3. After 1 hour the organic layer is washed with water and concentrated. It was obtained a crude 5-thia-l-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid, 7-(((2Z)-(2-amino-4-thiazolyl)(methoxyimino)acetyl)amino)-3-(methoxymethyl)-8-oxo-, l-(((l-methylethoxy)carbonyl)oxy)ethyl ester, (6R,7R)- (Cefpodoxime proxetil). Diastereoisomeric ratio 0.49. 

On one hand, the a,P-unsaturated lactone 40, which was derived from di-O-acetyl-L-rhamnal (39) according to reported procedures, was submitted to Mitsunobu inversion with HCO2H, followed by hydrolysis and methoxymethylation to afford 40. On the other hand, the o-methylbenzoate 41 was obtained from 3,5-dihydroxytoluene under the protocols described by Solladig. 

Starting from optically resolved carboxylic acid 215, the synthesis of bromide 218 encompassed three steps including performic acid treatment to 216, reductive fission of the lactone moiety to obtain 217, and double bromination. A three-step sequence involving mono-debromination, deacetylation and selective 2,3-O-isopropylidene protection converted 218 into exo-methylene precursor 219, on which C4 inversion to 220 was performed via mesylate. Changing the acetyl groups for methoxymethyl... 

Ac, acetyl AIBN, azobis(isobutanonitrile) All, allyl AR, aryl Bn, benzyl f-BOC, ferf-butoxycarbonyl Bu, Butyl Bz, benzoyl CAN, ceric ammonium nitrate Cbz, benzyloxycarbonyl m-CPBA, m-chloroperoxybenzoic acid DAST, diethylaminosulfur trifluoride DBU, l,8-diazabicyclo[5.4.0]undec-7-ene DCC, /V. /V - d i eye I oh e x y I c ar bo -diimide DCM, dichloromethyl DCMME, dichloromethyl methyl ether DDQ, 2,3-dichloro-5,6-dicyano-l,4-benzoquinone DEAD, diethyl azodicarboxylate l-(+)-DET, L-(+)-diethyl tartrate l-DIPT, L-diisopropyl tartrate d-DIPT, D-diisopropyl tartrate DMAP, 4-dimethylaminopyridine DME, 1,2-dimethoxyethane DMF, /V./V-dimethylformamide DMP, 2,2-dimethoxypropane Et, ethyl Im, imidazole KHMDS, potassium hexamethyldisilazane Me, methyl Me2SO, dimethyl sulfoxide MOM, methoxymethyl MOMC1, methoxymethyl chloride Ms, methylsulfonyl MS, molecular sieves NBS, N-bromosuccinimide NIS, /V-iodosuccinimide NMO, /V-methylmorpho-line N-oxide PCC, pyridinium chlorochromate Ph, phenyl PMB, / -methoxvbenzyl PPTs, pyridiniump-toluenesulfonate i-Pr, isopropyl Py, pyridine rt, room temperature TBAF, tetrabutylammonium fluoride TBS, ferf-butyl dimethylsilyl TBDMSC1, f-butylchlorodimethylsilane Tf, trifhioromethylsulfonyl Tf20, trifluoromethylsulfonic anhydride TFA, trifluoroacetic acid THF, tetrahydrofuran TMS, trimethylsilyl TPAP, tetra-n-propylammonium perruthenate / -TsOH. / -toluenesulfonic acid... 

Methylfluorene has been prepared by cleavage of ethyl 9-methyl-9-fluorenylglyoxylate,4 by the decarboxylation of 9-methylfluorene-9-carboxylic acid,4 by the decarboxylation of 9-fluorenylacetic acid,6 by the cleavage of 9-methyl-9-acetyl-fluorene with alcoholic potassium hydroxide or soda-lime,6 by the reduction of 9-methyl-9-fluorenol with hydriodic acid in acetic acid,7 by the reaction of 9-fluorenyllithium 8 or -sodium 9 with methyl iodide or methyl sulfate,9 by the cyclization of diphenylmethyl carbinol over platinum-on-carbon at 300°,10 by the reaction of ethyl 9-methoxymethyl-9-fluorcnylcarboxylate,u by the diazotization and heating of 2-ethyl-2-aminobiphenyl,12 by the dehydration and then reduction of 9-mcthyl-9-fluorcnol,13... 

Methoxy-1 -(2-mercapto-propyl)- 457 Methoxy-methyl- 581 4-Mcthoxy-l-methyl- 1157 2-Methoxymethyl-l-(methylmereaplo-acetyl)- 1024 4-Methoxymethylsulibn-l-methoxy- 1182 4-Methoxymethylsulfon-l -methyl- 1182 4-Mcthoxy- -phosphonsiiure-diathylester 1375... 

Acetyl-2-(methoxymethyl)-pyrrolidine is converted into 2-(methoxymethyl)-1-vinylidenepyrrolidinium triflate by treatment with 1 equiv of triflic anhydride (added over a period of 6 h) in CH2C12 at reflux in the presence of 1.2 equiv of collidine. The keteniminium salt 1 a is trapped in situ by 5 equiv of cyclopentene to give 2 and 3, after hydrolysis in water overnight yield 30% d.r. (2/3) 77 23. The enantiomeric excess (55%) and absolute configuration are determined by comparison with an authentic sample. 

Acetylation of (272) followed by exposure to osmium tetraoxide gave rise to diol acetate (273). Diol (273) was oxidized, the corresponding diketo acetate was hydrolyzed, and the resulting C(12) hydroxyl was reprotected as methoxymethyl ether, giving rise to (274). 

Chloromethyl methyl or ethyl ether, for instance, and KSCN in light petroleum form methoxymethyl or ethoxymethyl isothiocyanate, respectively,856 and 2,3,4,6-tetra-O-acetyl-a-D-glucopyranosyl isothiocyanate is obtained from a-acetobromoglucose and AgSCN in toluene.857... 

Acetylation. Either alcohols or methoxymethyl ethers are transformed into acetates in the FeClj -catalyzed acetylation, using HOAc and Ac O, respectively. 

Transetherification and transesterification. Tin(II) bromide is a catalyst for converting p-methoxybenzyl ethers into methoxymethyl ethers by CH2(OMe)2 and MeOCH2Br. Benzyl ethers and trimethylsilyl ethers are cleaved and acetylated in one operation by the action of SnBr2-AcBr in CH2CI2 at room temperature. 

A -methoxymethyl-amines or-amides A -acetyloxymethyl-amines or -amides or A/, iV-dimethylfonnamide acetals, all react with phosphorus(III) esters in non-classical Michaelis-Arbuzov fashion. From these and similar reactions, quaternary salts of the type 186 have been isolated. The A-methylated dervative may be preformed or produced in situ in mixtures containing amide, formaldehyde and phosphite ester. The products of the reactions are A-acylated (acetyl, benzoyl, phthaloyl, pyridinecarbonyl or benzyloxycarbonyl) when derived from amides, or A,A-dialkyl derivatives from hydroxy (or methoxy)methylamines the use of Me2NCH(OMe)2 leads to dimethylaminomethyl-enebisphosphonic esters. Ivanov and coworkers have made a detailed study of the reactions which occur between phosphorus(III) amides Et2NPYZ and the substrates, RCONHOAc (Scheme 16). The reagent can attack the substrate by virtue of the nucle-... 

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