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Glyoxal reduction

Preparation of the key tropine is achieved by any one of several variations on the method first developed by Robinson, which involves reaction of a primary amine with dihydroxyacetone and glyoxal. Reduction of the carbonyl group in the product (86) followed by acylation affords the aminoester (88). Transesterification with ester aldehyde 89... [Pg.160]

A special technique was necessary to obtain good yields of ethyl pyrrole-3-acetate from ethyl pyrrole-3-glyoxalate. Reduction over W-7 Raney Ni in 50% aq ethanol was accompanied by major ring reduction and tarring. By use of a two-phase system, toluene and 50% aq ethanol, these side reactions could be curtailed. Apparently the desired product was removed effectively from the aqueous layer into the toluene as soon as it was formed (26). [Pg.70]

Pig heart Lactate DH -17.5 -11.6 0.9 Glyoxalate reduction Pyruvate reduction/lactate oxidation Glyoxalate oxidation 430 192/85 115 Rel 71... [Pg.475]

Macrocycles have been prepared by formation of macrocyclic imines as well as by using variations of the Williamson ether synthesis ". Typically, a diamine or dialdehyde is treated with its counterpart to yield the Schiff s base. The saturated macrocycle may then be obtained by simple reduction, using sodium borohydride, for example. The cyclization may be metal-ion templated. In the special case of the all-nitrogen macrd-cycle, 15, the condensation of diamine with glyoxal shown in Eq. (4.14), was unsuccess-ful ... [Pg.164]

The nitration of 6-methoxyquinoxaline in concentrated sulfuric acid at 0°C gives 6-methoxy-5-nitroquinoxaline. The position of the nitro group is confirmed by reduction of the product to 5-amino-6-methoxy-quinoxaline identical with a sample prepared from 2,3,4-triamino-anisole and glyoxal ... [Pg.211]

Amino-5-hydrazinopyrazole dihydrochloride 300 is a good source for the synthesis of this type of heterocyclic compound [78JCS(P1)885] and it was prepared by reaction of malononitrile with two equivalents of hydrazine. Reaction of 300 with ethyl pyruvate afforded 301. Unstable hydra-zone 302 formed when 300 was boiled with diacetyl rapidly cyclized to 303. Reaction of 300 with benzil gave 304 directly, which gave an acetyl derivative and resisted reductive deamination. On the other hand, a polymer was isolated from the reaction of 300 with glyoxal (Scheme 65). [Pg.77]

Reductive coupling of unhindered N-alkylglucamines with glyoxal in the presence of Pd/carbon provides the corresponding N,N -dialkyl-N,N -di(l-deoxyglucityl)-ethylenediamines in good yield. Only minor amounts of byproducts are formed. [Pg.171]

In conclusion, N,N -dialkyl-N,N -di(l-deoxyglucityl)alkylenediamines (2) are prepared in good yield and purity by palladium-catalyzed reductive coupling of straight chain N-alkyl-(l-deoxyglucityl)amines with glyoxal. A wide variety of 2 with moderate to high hydrophobicity is readily accessible. [Pg.174]

Rhodium-catalyzed reductive coupling of 1,3-dienes, 1,3-diynes, or 1,3-enynes and glyoxals, and (iV-sulfinyl)imi-... [Pg.450]

To corroborate the proposed mechanism, the catalytic reductive aldol coupling of acrolein with phenyl glyoxal monohydrate was performed under 1 atmos. elemental deuterium. Exposure of the aldol product to excess hydrazine in situ results in formation of the pyridazine, which incorporates precisely one deuterium atom in a manner consistent with the general mechanism proposed in Scheme 22.4 (Scheme 22.9). [Pg.721]

Scheme 22.9 Intermolecular reductive aldol coupling of acrolein and phenyl glyoxal under a D2 atmosphere.a)... Scheme 22.9 Intermolecular reductive aldol coupling of acrolein and phenyl glyoxal under a D2 atmosphere.a)...
Scheme 22.11 Reductive coupling of 1,3-cyclohexadiene and 2-naphthyl glyoxal under an atmosphere of D2(g). Scheme 22.11 Reductive coupling of 1,3-cyclohexadiene and 2-naphthyl glyoxal under an atmosphere of D2(g).
Scheme 22.13 Reductive coupling of 1-phenyl but-3-en-l-yne with phenyl glyoxal. Scheme 22.13 Reductive coupling of 1-phenyl but-3-en-l-yne with phenyl glyoxal.
Scheme 22.15 Reductive coupling of diphenylbutadiyne with phenyl glyoxal. Scheme 22.15 Reductive coupling of diphenylbutadiyne with phenyl glyoxal.
The preparation of vicinal diallyldiamines is illustrated by the following sequence condensation of glyoxal with benzhydrylamine yields the diimine 189, which is converted into 190 by the action of allylmagnesium chloride. The diphenylmethyl groups are then removed reductively by treatment with triethylsilane196. [Pg.570]

The one-electron reduction of 3,4,5-trimethoxyphenyl glyoxal with potassium tert-butoxide in DMSO gives rise mainly to the ctT-semidione, whereas on electrolysis in dimethylformamide, in the presence of tetraethylammonium perchlorate as the carrier electrolyte, the main product is the trans isomer (Sundaresan and Wallwork 1972 Scheme 3.47). [Pg.171]


See other pages where Glyoxal reduction is mentioned: [Pg.1209]    [Pg.469]    [Pg.599]    [Pg.599]    [Pg.478]    [Pg.1209]    [Pg.469]    [Pg.599]    [Pg.599]    [Pg.478]    [Pg.193]    [Pg.125]    [Pg.211]    [Pg.257]    [Pg.172]    [Pg.99]    [Pg.105]    [Pg.106]    [Pg.69]    [Pg.120]    [Pg.121]    [Pg.123]    [Pg.469]    [Pg.354]    [Pg.723]    [Pg.724]    [Pg.726]    [Pg.727]    [Pg.727]    [Pg.729]    [Pg.548]    [Pg.71]    [Pg.68]    [Pg.274]   


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