Glyoxylic acid methyl ester

Scheme 11.13 Dihydroxylation of alkenes in the presence of glyoxylic acid methyl ester methyl hemiacetal (33) [94k].

More recently, the use of glyoxylic acid methyl ester hemiacetal as a cocatalyst was shown to afford an even more effective epoxidation catalyst, enabling high conversions with only a 30% excess of hydrogen peroxide. Interestingly, the corresponding cfs-diols were observed as by-products in many cases and a concerted mechanism via a manganese(III)-cfs-diol complex was proposed to explain their formation. 

Recently, greatly enhanced ds-dihydroxylation activity was observed using [Mn203(tmtacn)2](PF6)2 4 (Figure 10.2) in the combination with glyoxylic acid methyl-ester methyl hemiacetal (gmha 32, Scheme 10.15) [96]. 

Glycothioses, I, 135 Glycuronide, III, 131 Glyoxal, methyl-, phytochemical reduction of, IV, 80 —, methyl-, III, 127 phenylosazone, III, 117, 122 Glyoxylic acid, ethyl ester, II, 89 IV, 128 Goepp, Rudolf Maximilian, Jr., obituary, III, xv-xxiii... 

Glyoxylic acid Et ester, in G-00038 >4-Methyl-l,3-dioxoIan-2-one, M-00160 Pyruvic acid Me ester, in P-00448... 

ASYMMETRIC CATALYTIC GLYOXYLATE-ENE REACTION METHYL (2R)>2 HYDROXY-4-PHENYL-4 PENTENOATE (Benzenabutanoic acid, a-hydroxy-y-methylene, methyl ester, (R)-)... 

An unusual method for chain termination is utilized in the biosynthesis of myxothiazol and melithiazol. The domains in the terminal modules of these synthetases are arranged in the following order C-A-MOx-A-PCP-TE (MOx = monooxygenase domain). In the termination modules of these synthetases, the MOx domain likely catalyzes hydroxylation of the ct-carhon of the C-terminal glycine residue of the requisite peptidyl-5-PCP. The resulting intermediate then undergoes spontaneous conversion into PCP-bound glyoxylic acid and a terminal amide. This sequence yields the final product in the case of myxothiazol, whereas the terminal amide is transformed to a methyl ester to complete melithiazol biosynthesis. 

Formaldehyde, -acetaldehyde, propionaldehyde, methyl glyoxylic acid, pymvic acid Converted to benzyl esters, then GLC [598]... 

Glyoxal-sodium bisulfite, 30, 86 GlYOXYLIC acid, n-BUTYL ESTER, 35, 18 ETHYL ESTER, DIETHYL ACETAL, 35, 59 Grignard reaction, addition to ethyl sec-butylidenecyanoacetate, 35, 7 allylmagnesium bromide with o , 8-di-bromoethyl ethyl ether, 36, 61 allylmagnesium chloride with a,/3-di-bromoethyl ethyl ether, 36, 63 ethylmagnesium bromide with tin tetrachloride, 36, 86 N-methyl-l,2-diphenylethylamine,... 

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