Oxo a-methylation

Oxo-a-methyl-K.a,ai -triphenyl-tri> methylenimin Oder a -Oxo- -methyl-N.a.d-tiiphenyl-trimethylei in 211 314. 

Isobutyraldehyde is commonly available as a by-product of propylene/Oxo hydroformylation. Methyl isoamyl ketone is used as a solvent for ceUulose esters, acryHcs, and vinyl polymers. It is available in the United States from Eastman (Kingsport, Tennessee) (47) and Union Carbide (South Charleston, West Virginia) and was priced at 1.42/kg in October 1994. 

Pyridazines with a hydroxy group at an a- or y-position to a ring nitrogen atom, i.e. 3-and 4-hydroxypyridazines (4) and (5), exist predominantly in the oxo form. This conclusion is based on spectroscopic evidence from UV spectra of unsubstituted compounds and their A-methyl and O-methyl derivatives in alkaline, neutral and acidic solutions. In some instances, as for example for 6-oxo-l,6-dihydropyridazine-3-carboxamide, there is also evidence from X-ray analysis <54AX199, 63AX318). Maleic hydrazide and substituted maleic hydrazides exist in the monohydroxymonooxo form (6). 

Alkylation of these mercapto compounds in alkaline solution gives only the S-methyl derivatives. Of the four isomeric A-methyl derivatives, the 4-thioquinazolines, (28) and (29), have been obtained from the corresponding oxo compounds with phosphorus pentasulfide but the corresponding 2-thio derivatives (30) and (31) are not known. However, derivatives of substance (31) with methyl replaced by... 

Recently, many investigators have extended the early observations that the ultraviolet spectra of - and y-hydroxypyridines resemble those of their A -methyl (not the 0-methyl) derivatives. This spectral resemblance is found both in aqueous solutions and in solutions of solvents with low dielectric constants, e.g., quinol-4-one in benzene, indicating that these compounds exist predominantly in the oxo form under all conditions. These data are summarized in Table I. In contrast, 4-hydroxyquinoline-3-carboxylic acid has been tentatively concluded to exist in the hydroxy form %- pjTid-2-one-4-carboxylic acid has also been formulated as a hydroxy compound, but this has been disputed. ... 

The isolation of two tautomers of 2,3,4-trihydroxyquinoline has been reported but one was later identified as the isomeric 1,2,4-trihydroxy compound 47. The fact that 2,3,4-trihydroxyquinoline is oxidized more slowly than its A -methyl derivative was considered to show that it existed in an oxo form. The product resulting from... 

Between 1951 and 1953 investigations by three English groups clearly demonstrated the preponderance of the oxo forms of pyrimidin-2- and -4-ones by comparing the ultraviolet spectra of these compounds with those of the N and 0-alkylated derivatives, The o-quinonoid form 91 (R = H) is favored by the evidence that A -methylation of the 6-methyl derivative of 89a does not cause a bathochromic shift in the ultraviolet spectrum (A -methylation of pyrid-4-one causes a bathochromic shift, but this is not observed for pyrid-2-one) The isomeric A -methyl derivatives of pyrimidin-4-ones [e.g., 91 (R = Me) and 90 (R = Me)] form similar cations (e.g., 92 and 93), and hence the equilibrium constant between... 

Quinazolin-4-one and its 6-nitro derivative were both shown to exist predominantly in the o-quinonoid form (cf. 96) by ultraviolet spectral comparisons of the parent compound with the 0-methyl derivative and with the two A -methyl analogs, The existence of quinazolin-2- and -4-ones in an oxo-type structure was demonstrated in 1952 by using solid-state infrared data and later confirmed by... 

Alkylation at the ind-N of l,2,3,4-tetrahydro-j8-carbolines has been carried out with alkyl halide after treatment with sodamide in the usual manner. Cyanoethylation of a p /r-V-substituted tetrahydro-jS-carboline in the presence of Triton B yields the corresponding 9-cyanoethyl derivative. Similarly, treatment of p / -V-methyl-l,2,3,4,4a,9b-hexahydro-y-carboline with sodamide, followed by benzyl chloride, leads to the ind-A -benzyl-substituted derivatives. l-Oxo-l,2,3,4-tetrahydro-j8-carboline yields the ind-A -methyl derivative directly with dimethyl sulfate.Prolonged treatment with sodium hydride, followed by methyl iodide, yields the 2,9-dimethyl derivative. Heating with sodium hydride in acetone followed by the addition of dimethyl sulfate gives rise to the ind-V-methyl derivative. ... 

A sulfoxide was obtained by oxidation of 8-[(4-trifluoromethylmercapto-phenyl)methoxy] derivative 358 with 36% H2O2 in AcOH (98MIP7) and by oxidation of l-[2-(4-thiomorfolin-l-yl)acetyl]-7-(3-methoxyphenyl)-A-methyl-A- [3,5-bis(trifluoromethyl)phenyl]ethyl -5-oxo-1,2,3,5-tetrahydro-pyrido[l,2,3-i/ ]quinoxaline-6-carboxamide with 3-chloroperbenzoic acid (01MIP12). A 7-[(4-fluorophenylsulfonyl)methyl] derivative was obtained by oxidation of a 7-[(4-fluorophenylsulfanyl)methyl]perhydropyrido[l,2-u] prazine with 3-chloroperbenzoic acid in CHCI3 (01EUP1074257). 

Dioxo-2,3-dimethyl-1,2,3,4-tetrahydro-phthalazin wird in Acetat-Puffer im we-sentlichen zuml-Oxo-2,3-dimethyl-l,2,3,4-tetrahydro-phthalazin (80% d.Th.) reduziert, in 4n Salzsaure wird dagegen unter Methylamin-Abspaltung 1 -Oxo-2-methyl-2,3-dihy-dro-isoindol (46% d.Th.) erhalten1 (vgl. a. S. 595f.) ... 

Die Reduktion von cis- und frarcs-a,/3-Diacetoxy-stilben in DMF/Tetrabutylammo-niumjodid an Quecksilber (-1,5 V vs. Ag/AgJ) fiihrt zu Tolan und bei —1,8 Volt zu trans-Stilben2. 2-Oxo-4-methyl-l,3-dioxolan wird an Graphit mit Lithiumperchlorat als Leitsalz unter C-O-Spaltung zu Propen reduziert3 ... 

CN stereoisomer of /V,iV-[(2-amino-4,6-dimethyl-3-oxo-377-phenoxazine-l,9-diyl)bis[carbonylimino[2-( 1 -hydroxyethyl)-1 -oxo-2,1 -ethanediyl]imino[2-( 1 -methylethyl)-1 -oxo-2,1 -ethanediy 1]-1,2-pyrrolidinediylcarbonyl(methylimino)(l-oxo-2,l-ethanediyl)]]bis[A/-methyl-L-valine] di- -lactone... 

C ,H6 N204PS2Si 128778-86-9) see Tacrolimus [2S-[2a(R ),3p(5 )]]-3-[l-[[(l,l-dimethylethyl)dimethyl-silyl]oxy]ethyl]-a-methyl-4-oxo-2-azetidineacetic acid phe-nylmethyl ester... 

CifiHpNO, 33522-95-1) see Nalbuphine Naloxone 2 -hydroxy-4 -(2,5-dihydro-5-oxo-3-furyl)acetophenone (C12H10O4 3447-63-0) see Benfurodil hemisuccinate 0-(4-hydroxy-3,5-diiodophenyl)-3,S-diiodo-a-methyl-tyrosine... 

A -methyl-9,10-ethanoanthracene-9(10ll)-propanamide (C20H21NO 23716-34-9) see Maprotiline [liJ-[ltt,5a,6(7J )]]-a-(l-methylethenyl)-7-oxo-3-phenyl-4-oxa-2,6-diazabicyclo[3.2.0]hept-2-ene-6-acetic acid diphe-nylmethyl ester... 

Dihydro-3-methoxy-4-methyl-5-oxo-A/-[[2-(tri-fluoromethoxy)phenyl]sulfonyl]-1H-1,2,4-triazole-1-carboxamide, sodium salt... 

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