Butyl glyoxalate

One of the key steps used in a new synthesis of the bis(tetrahydrofuran) moiety of Asteltoxin (94) is the photoaddition of the propanal (95) to 3,4-dimethylfuran, yielding the adduct (96). This cycloaddition is a common outcome of the irradiation of aldehydes or ketones with furans. An analogous adduct (97) results from the photoreaction of butyl glyoxalate with 2-methylfuran. Two other products [(98) and (99)] are also formed, the first of which is presumably the result of ring opening of the isomeric oxetane (100), while (99) is produced by a hydrogen abstraction radical coupling pathway. 

The first report of a chiral aluminum Lewis acid employed in a heteroatom Diels-Alder reaction utilized Koga s mentholoxy dichloroaluminum catalyst 4 [75]. trans-Piperylene and 1-methoxybutadiene were reacted with n-butyl glyoxalate and diethyl mesoxalate the results are summarized in Sch. 46. The asymmetric induction and chemical yield in these reactions are quite poor but the authors did find that moderate asymmetric induction could be obtained from reactions catalyzed by Eu(hfc)3. 

Otlier preparative methods for phosphorylglycines include the addition of sodium diethyl pliosplute to the Schiff base prepared from benzylamine and ethyl or ferf-butyl glyoxalate - the reaction of McjSiBr with the triethoxyphosphorane prepared from Af-protected alkyl oxalamides and trietliyl phosphite and the Rh(II)-catalyzed N-H insertion of diethyl 1-ethoxycarbonyl-l-diazomethylphosphonate into carbamates. 

The completely unsubstituted pyrrolo[l,2-c]pyrimidine 127 has been synthesized from 4-methylpyrimidine and butyl glyoxalate in seven synthetic steps85 (Scheme 8). This last step proceeds in only 9% yield, probably a reflection of the poor nucleophilicity of the pyrirhidine nitrogen atom. Compound 127 melts at 36°-39°, is highly volatile, and darkens slowly in air. 

Glyoxal-sodium bisulfite, 30, 86 Glyoxylic acid, w-butyl ester, 35, 18 ethyl ester, diethyl acetal, 35, 59 Grignard reaction, addition to ethyl sec-butylidenecyanoacetate, 35, 7 allylmagnesium bromide with of,(3-di-bromoethyl ethyl ether, 36, 61 allylmagnesium chloride with a,/3-di-bromoethyl ethyl ether, 36, 63 ethylmagnesium bromide with tin tetrachloride, 36, 86... 

Glutaronitrile, 3-hydroxy-, 46, 48 Glycerol chlorohydrin, 46, 24 Glycine (-butyl ester, 45, 47 conversion to acetamidoacetone, 45,1 Glyoxal, phenyl-, 48,109 Glyoxals from esters and the potassium salt of dimethyl sulfoxide, 48, 112... 

Investigation of the mechanism of these reactions has suggested ways in which the yields can be improved. Acidic conditions (pH 2) will prevent Cannizzaro rearrangement of any glyoxal-type species and also serve to hydrolyse any Schiff bases which result from side reactions of aldehyde and amine. Conditions should be adjusted so that the rate of hydrolysis of linear products is equal to the rate of cyclocondensation, allowing accumulation of the imidazole products. From glyoxal, formaldehyde and ammonium chloride the yield of imidazole can be inereased to 85% by careful control of the conditions. With an appropriate alkylammonium chloride, 1-substituted imidazoles are also accessible (e.g. 1-methyl (56%), 1-isopropyl (46%), 1-cyclohexyl (49%), 1-n-butyl (55%), 1-t-butyl (25%)). The process may have some applications, but yields drop off with branched alkyl compounds [22 j. Imidazolium salts are also available under similar conditions when two molar equivalents of a primary alkylamine are used [23]. 

Glycyl-L-leucine Glyoxal 1 -(1 -Carboxy-3 -methy 1-butyl)-2-oxo-l, 2-dihydro 380... 

The prototype reaction is the conversion of glyoxal into glycolic acid (equation 2), and here the benzilic acid rearrangement mechanism coincides with that for an intramolecular Cannizzaro reaction. The reaction is observed with other purely aliphatic a-diketones such as f-butyl 2,3-dioxobutyrate and cyclohexane-1,2-dione (equations 3 and 4), but the scope is limited in the aliphatic series by competing (c.g. aldol) reactions. Suitably constructed heterocyclic systems also rearrange, and the conversion of alloxan (3) into alloxanic acid (4) was among the first of the benzilic acid rearrangements to be discovered (equation 5). ... 

An aqueous solution of glyoxylic acid reacts with cyclopentadiene to provide a-hydroxy-y-lactones the more acidic the solution, the faster the reaction (Scheme 13) [68]. Thus at pH 0.9 (2.25 M glyoxylic acid solution in water) the reaction is complete after 90 min at 40 °C providing a 83 % yield of a-hydroxy-y-lactones. In the case of cyclohexadiene, the reaction is complete after 2 days at 90 °C in water, compared to 21 h at 120 °C for the reaction with butyl glyoxylate in neat conditions (Scheme 13). These results show that it is possible to exploit the die-nophilic character of a carbonyl group in water in spite of its quasi total hydration. Pyruvaldehyde, glyoxal, and even ketones like pyruvic acid, also react with dienes in water [69]. 

S-butyl, and isobutyl. They are considered to be the compounds which give peas their characteristic flavor (and odor) and are estimated to be present to the extent of one part in 10 to 10 parts. They have also been detected in oil from Ferula species (Umbelliferae) and the last-mentioned was detected in bellpeppers (Solanaceae). Their biogenetic origin is reasoned to be analogous to their laboratory syntheses from simple derivatives of known amino acids and glyoxal (210). 

Acetic acid, oleyl ester. See Oleyl acetate Acetic acid, oxo-. See Glyoxalic acid Acetic acid palladium salt Acetic acid palladium (2+) salt. See Palladium diacetate Acetic acid pentyl ester. See Amyl acetate Acetic acid, phenyl-, butyl ester. See Butyl phenylacetate... 

Amyl acid phosphate Saccharin sodium anhydrous Saccharin sodium dihydrate accelerator, ripening sugarcane Glyoxalic acid accelerator, rubber Aniline 2-Benzothiazyl-N,N-diethylthiocarbamyl sulfide 2-Benzothiazyl-N-morpholine disulfide Benzyl chloride 1,3-Bis (2-benzothiazolylmercaptomethyl) urea Butyl 2-benzothiazole sulfenamide n-Butyraldehyde Cadmium... 

Bisphenol A Glyoxal 4,4 -Methylenedianiline m-Phenylenediamine Phenyl glycidyl ether Tetrahydrophthalic anhydride curing agent, bricks Fluosilicic acid curing agent, butyl rubber Lead dioxide... 

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