Preparation Of Methyl Research Articles

A facile preparation of alkyl α-glycosides of the methyl ester of N-acetyl- d-neuraminic acid

The reaction of methyl 5-acetamido-4,7,8,9-tetra- O-acetyl-2-chloro-2,3,5-trideoxy-β- d- glycero- d- galacto-2-nonulopyranosonate with primary and secondary alcohols in the presence of silver salicylate affords, after O-deacetylation, stereo-specifically the corresponding methyl (alkyl 5-acetamido-3,5-dideoxy-α- d- glycero- d- galacto-2-nonulopyranosid)onates. The preparation of methyl(neopentyl 5-acetamido-3,5-dideoxy-α- d- glycero- d- galacto-2-nonulopyranosid)onate in benzene solution shows that this glycosylation can be carried out in an inert solvent.

Preparation of methyl and acetyl complexes of iron(II)

The complexes [Fe(CO)2(PMe3)2(Me)X], where X = Br, Cl, CN, NCS, CNO, OMe, or Me, have been synthesized and the structure assigned on the basis of i.r. and n.m.r. evidence. The complexes react readily and reversibly with CO to give the acetyl derivatives with the acetyl group in the cis position relative to X. When X = I, Br, or Cl the cis isomer rearranges slowly to the trans isomer until an equilibrium is obtained. The results are interpreted in terms of the σ- and π-accepting capabilities of the ligands.

Mevinic acids and analogues: preparation of a key chiral intermediate

The preparation of methyl 3-0-tert-butyldiphenylsilyl-2,4-dideoxy-β- D - erythro - hexopyranoside, a key chiral intermediate for mevinic acids, and its elaboration into four mevinate analogues are described.

Preparation of methyl 10-oxo-15S-hydroxyprosta-5E,13Z-dienoate

The synthesis of methyl 10-oxo-15S-hydroxyprosta-5E,13Z-dienoate is described.

Synthesis of 1-, 6- and 1,6-derivatives of methyl D-fructofuranosides

A variety of derivatives of methyl α- and β-D-fructofuranosides modified at C1 or C6, or at C1 and C6, have been prepared in which the hydroxyl group(s) has been replaced by azido, amino, chloro, bromo, hydrogen and thiol acetate functions. These compounds were made by displacements on methyl 1,6-di-O-p-toluenesulfonyl-D-fructofuranosides, or on 2,3-O-isopropylidene-l,6-di-O-p- toluenesulfonyl-β-D-fructofuranose and subsequent glycosidation. A number of indirect methods of preparation of methyl D-fructofuranosides, mostly based on 1,3,4,6-tetra-O-benzoyl-D-fructofuranose have been investigated.

Studies on furan derivatives. XII. Nucleophilic substitution of methyl 5‐nitro‐2‐furancarboxylate. Preparation of methyl 5‐phenoxy‐2‐furancarboxylates

AbstractTwenty one methyl 5‐phenoxy‐2‐furancarboxylates prepared from the reaction of methyl 5‐nitro‐2‐furan‐carboxylate with phenoxides via displacement of the nitro group. In the reaction of potassium 2‐nitrophen‐oxide with methyl 5‐nitro‐2‐furancarboxylate at 110°‐120°, 2,2′‐dinitrodiphenyl ether was obtained as a main product.

Preparation of methyl 4,6- O-benzylidene-2-deoxy-2-nitro-α- d-glucopyranoside from the corresponding 2-oximino derivative

Preparation of methyl 4,6- O-benzylidene-2-deoxy-2-nitro-α- d-glucopyranoside from the corresponding 2-oximino derivative

ChemInform Abstract: TOTAL SYNTHESIS OF ANDROSTANES

AbstractCycloaddition von (I) an das Dienophile (II) unter SnCl4‐Katalyse gibt das Tricyclodienon (III), das zu (IVa) ketalisiert wird.

Preparation of methyl 4,6- O-benzylidene-2,3-dideoxy-2,3-dinitro-α- D-glucopyranoside and its selective conversion into the corresponding 2-nitro-2-enopyranoside

Treatment of methyl 4,6- O-benzylidene-2,3-dideoxy-3-nitro-α- D- erythro-hex-2-enopyranoside ( 3) with sodium nitrite in benzene-water in the presence of small amounts of tributylhexadecylphosphonium bromide as a phase-transfer catalyst afforded the 2-nitro alkene 4 in 47% yield. A similar reaction in the presence of 1.3 equiv. of acetic acid gave the 2,3-dinitro derivative 5 in 58% yield; it was selectively converted into the 2-nitro alkene 4. In these reactions, nitrite ion undergoes addition from the axial and equatorial sides of 3 and 4, respectively.

Total synthesis of androstanes

A total synthesis of androstane derivatives is described. The desired configuration at C8 and at C13 is achieved in a ring C forming SnCl4-catalyzed Diels–Alder reaction. The preparation of methyl Z-2-methyl-4-oxo-2-pentenoate and the cyclization of a keto ester to a steroid 15,17-dione are also reported.

Method for preparation of methyl 3-(2,2-dimethyl-4-tetrahydropyranyl)-3-oxopropionate

A method is proposed for the synthesis of methyl 3-(2,2-dimethyl-4-tetrahydropyranyl)-3-oxopropionate on the basis of 2,2-dimethyl-4-ethynyltetrahydro-4-pyranol.

Über die Herstellung des Methyl‐α‐D‐fructopyranosides und die Struktur der dabei gebildeten Orthoester

Concerning the preparation of methyl α‐D‐fructopyranoside and the structure of the orthoester by‐productsKoenigs‐Knorr glycosidation (AgClO4/Ag2CO3) of the easily accessible p‐nitrobenzoylated fructosylchloride 7 yields mainly the protected glycoside 3 which was deacylated to the known title compound 1. The orthoesters 15 and 16 were formed as by‐products in this glycosidation whilst the analogous orthoesters 21 and 22 are formed as main products in the glycosidation (Ag2CO3) of the benzoylated fructosylchloride 12. The structure of these orthoesters was deduced mainly from their spectroscopic data, from those of their derivatives 17, 18, 19, 20, 25 and 26 and by comparison of the latter with the model compounds 31 and 34.

Preparation of secopenicillanates; preparation of methyl 3-methyl-2-[(2R,3R)-2-methylthio-4-oxo-3-phthalimidoazetidin-1-yl]but-2-enoate

Treatment of methyl (1R,6R)-1-oxo-6-phthalimidopenicillanate (4) with trimethyl phosphite gives a mixture of bis-{(2R,3R)-1-[(1R)-1-methoxycarbonyl-2-methylprop-2-enyl]-4-oxo-3-phthalimidoazetidin-2-yl} disulphide (12)(25–60%) and methyl (2R)-3-methyl-2-[(2R,3R)-2-methylthio-4-oxo-3-phthalimidoazetidin-l-yl]but-3-enoate (11)(15-35%). The latter compound was also prepared by heating methyl (1R,6R)-1-oxo-6-phthalimidopenicillanate sulphoxide in 2-methylpropane-1-thiol, under reflux, to give the unsymmetrical disulphide (21) which was cleaved by trimethyl phosphite to give the non-conjugated secopenicillanate (11). Conversion of the non-conjugated secopenicillanate (11) into methyl 3-methyl-2-[(2R,3R)-2-methylthio-4-oxo-3-phthalimido azetidin-1-yl]but-2-enoate (2) was achieved using a catalytic amount of diazabicyclononene (DBN) at room temperature. Prolonged treatment with DBN under reflux in benzene, gave a mixture of the conjugated secopenicillanate (2) and its 3′-epimer (22) in a ratio of 3 : 7.

アルキルβ‐フルクトフラノシド調製の改良法

アルキルβ‐フルクトフラノシド調製の改良法

Preparation of Methyl 4,6- O-benzylidene-2-deoxy-2-nitro-β-D-glucopyranoside from the corresponding 3-deoxy-3-nitro derivatives with sodium nitrite

Treatment of methyl 4,6- O-benzylidene-2,3-dideoxy-3-nitro-β- D- erythro-hex-2-enopyranoside ( 2) with nitrous acid afforded the title 2-nitro sugar ( 4). The same product was also prepared by heterogeneous reaction of methyl 2- O-acetyl-4,6- O-benzylidene-3-deoxy-3-nitro-β- D-glucopyranoside ( 1) with sodium nitrite in the presence of a phase-transfer catalyst. Acid hydrolysis of 4 gave methyl 2-deoxy-2-nitro-β- D-glucopyranoside ( 7). Acetylation of 4, followed by elimination of acetic acid, afforded a 2-nitroalkene ( 6). 71e 3-acetate 5 reacted with ammonia, dimethylamine, and 2,4-pentanedione to give the products 8, 9, and 10, respectively, having the gluco configuration.

Syntheses of tetra- and hexadeuterated octadecenoates.

A study of the metabolism in man of cis and trans monoenoic acids required the synthesis of tetra- and hexadeutero-9-octadecenoates. Preparation of methyl 9-octadecenoate-8,8,11,11-d4 (90 mol % deuterium) by the Wittig reaction was accompanied by deuterium scattering with sodium methoxide as the base but not with alkylithium. Scattering occurred in both the aldehyde and phosphorane moieties only when the aldehyde contained deuterium on the alpha carbon. Methyl 9-octadecenoate-8,8,13,13,14-14-d6 (98 mol % deuterium) was also prepared by the Wittig reaction. The deuterated octadecenoates were formed principally as cis isomers. The trans isomers were produced by nitrogen oxide isomerization and separation on a silver ion column.

New method for the preparation of methyl threo-α-phenyl-α-(2-piperidyl)acetate hydrochloride

New method for the preparation of methyl threo-α-phenyl-α-(2-piperidyl)acetate hydrochloride

Isonucleosides. I. Preparation of methyl 2-deoxy-2-(purin-9-yl) arabinofuranosides and methyl 3-deoxy-3-(purin-9-yl) xylofuranosides.

Isonucleosides. I. Preparation of methyl 2-deoxy-2-(purin-9-yl) arabinofuranosides and methyl 3-deoxy-3-(purin-9-yl) xylofuranosides.

Synthesis of methyl gentosaminide, methyl 3-deoxy-3-methylamino-arabinopyranoside, and related amino-sugars.

The synthesis of both α- and β-anomers of methyl gentosaminide (methyl 3-deoxy-3-methylamino-D-xylopyranoside), a component of the amino-glycoside antibiotics gentamicin A and 66-40B, is described. A number of novel 3-alkylamino-analogues of gentosamine have been prepared and the synthesis of the L-enantiomer is also discussed. The preparation of methyl 3-deoxy-3-methylamino-α-D-arabinopyranoside and of the L-enantiomer, involving use of novel epoxy-ketone intermediates, is described. The L-enantiomer has recently been demonstrated to be a component of the amino-glycoside antibiotics 66-40D and gentamicins A1, A3, and B2.

Preparation of methyl 3-amino-3,6-dideoxy-β-D-hexopyranosides by condensation of (2R,4R)-2-methoxy-4-methyl-3-oxapentane-1,5-dial with nitromethane

Preparation of methyl 3-amino-3,6-dideoxy-β-D-hexopyranosides by condensation of (2R,4R)-2-methoxy-4-methyl-3-oxapentane-1,5-dial with nitromethane