Oxalyl-acetic ester

Sometimes the oxalic ester only undergoes lialf-coudensation as in the formation of oxalyl acetic ester ... 

Citric ester has been synthesised in this way from brom-acefcic ester and oxalyl-acetic ester 5... 

Oxalyl-acetic ester (20 gms.) is mixed with mono-bromacetic ester (17 gms.) in a flask of 300 c.c, capacity, fitted with an air-condenser. Enough zinc turnings to cover the end of a spatula are added and the mixture becomes brown, while the temperature quickly reaches 50° and the zinc dissolves. Addition of a second portion of zinc is attended by boiling and the reaction is moderated by cooling the metal is added in excess, and the mixture is then heated on the water-bath for a short time. After cooling, the mixture is treated with cold dilute sulphuric acid and ether, well shaken to get a clear solution, and the ethereal layer removed, washed with dilute sodium carbonate and dried over calcium chloride. The ether is next distilled and the remaining oil fractionated under reduced pressure most of it passes over below 200° at 35 mm. That portion taken as citric ester (b.p, 212°—216°) is hydrolysed... 

Reaction of (S)-(+)-2-aminobutyrate hydrochloride with ethyl oxalyl chloride followed by replacing of the ethyl ester with amino alcohol, oxidation with Dess-Martin periodinate and cyclization using TFA/TFAA in acetic acid gave the cyclic product, which was further converted to the bromide. Sub-... 

Synthesis of isomeric chiral protected (63 )-6-amino-hexahydro-2,7-dioxopyrazolo[l,2- ]pyrazole-l-carboxylic acid 280 is shown in Scheme 36. Crude vinyl phosphonate 275, obtained by treatment of diethyl allyloxycarbonylmethyl-phosphonate with acetic anhydride and tetramethyl diaminomethane as a formaldehyde equivalent, was used in the Michael addition to chiral 4-(f-butoxycarbonylamino)pyrazolidin-3-one 272. The Michael addition is run in dichloro-methane followed by addition of f-butyl oxalyl chloride and 2 equiv of Huning s base in the same pot to provide 276 in 58% yield. The allyl ester is deprotected using palladium catalysis to give the corresponding acid 277, which is... 

Acyl hydrazides are useful precursors for the synthesis of 1,2,4-triazoles. Reaction of acyl hydrazides 149 with imidoylbenzotriazoles 148 in the presence of catalytic amounts of acetic acid under microwave irradiation afforded 3,4,5-trisubstituted triazoles 150 <06JOC9051>. Treatment of A-substituted acetamides with oxalyl chloride generated imidoyl chlorides, which reacted readily with aryl hydrazides to give 3-aryl-5-methyl-4-substituted[ 1,2,4]triazoles <06SC2217>. 5-Methyl triazoles could be further functionalized through a-lithiation and subsequent reaction with electrophiles. ( )-A -(Ethoxymethylene)hydrazinecarboxylic acid methyl ester 152 was applied to the one-pot synthesis of 4-substituted-2,4-dihydro-3//-1,2,4-triazolin-3-ones 153 from readily available primary alkyl and aryl amines 151 <06TL6743>. An efficient synthesis of substituted 1,2,4-triazoles involved condensation of benzoylhydrazides with thioamides under microwave irradiation <06JCR293>. 

Several laboratories have reported that Swern oxidation of alcohols can be accompanied of a-chlorination of keto or (1-keto ester groups. Undesired electrophilic chlorination can be avoided by use of oxalyl chloride (1.05 equiv.) and DMSO (2.5 equiv.) in stoichiometric amounts or by use of acetic anhydride or trifluoroacetic anhydride in place of oxalyl chloride.1... 

Aminothiazole, with acetaldehyde, 42 to 2-mercaptothiazoie, 370 4-Aminothiazole-2,5-diphenyl, to 2,5 di-phenyl-A-2-thiazoline-4-one, 421 Ammothiazoie-A -oxide, 118 2-Aminothiazoles. 12 acidity of, 90 and acrylophenone, 42 acylations of, with acetic acid. 53 with acetic anhydride, 52 with acyl halides, 48 with chloracetyl chloride, 49 with-y-chlorobutyrylchloride, 50 with 0-chloropropionylchloride, 50 with esters, 53 with ethy acrylate, 54 with indoiyl derivatives, 48 with malonic esters, 55 with malonyl chloride, 49 with oxalyl chloride, 50 with sodium acetate, 52 with unsaturated acyl chloride, 49 additions to double bonds, 40 with aldehydes, 98 alkylations, with alcohols, 38 with benzyhydryl chloride, 34 with benzyl chloride, 80 with chloracetic acid, 33 with chloracetic esters, 33 with 2-chloropropionic acid, 32 with dialkylaminoalkyl halides, 33 with dimethylaminoethylchloride, 35 with ethylene oxide, 34, 38... 

Protection of aldoses at the non-anomeric positions makes it possible to use many of the common procedures in organic chemistry for oxidizing lactols as shown with mannofura-nose 1 and glucopyranose 3 (O Table 1). The reactions can be divided into three main categories oxidations mediated by activated dimethyl sulfoxide (DMSO), oxidations with chromi-um(VI) oxides, and oxidations catalyzed by ruthenium oxides. The DMSO-mediated oxidations of alcohols can be promoted by several activators [27]. With the partially protected aldoses the activation has mainly been achieved with acetic anhydride and oxalyl chloride. Competing /3-elimination does usually not occur unless the eliminating group is an ester, e. g., an acetate or a benzoate [27]. 

Ethyl oxalyl chloride Acetic acid, chlorooxo-, ethyl ester (4755-77-5), 76, 142... 

A few years later the Swem laboratory then developed an activator which they claimed to be the most successful in activating dimethyl sulfoxide toward oxidation, namely, oxalyl chloride. Since oxalyl chloride reacted violently and exothermically with dimethyl sulfoxide, successful activation required the use of low temperatures to form the initial intermediate.6 Swem et al. reported the oxidation of long chain primary alcohols to aldehydes which was previously unsuccessful by first converting to the sulfonate ester (either mesylate or tosylate) and then employing the dimethyl sulfoxide-acetic anhydride procedure. They found that long-chain saturated, unsaturated, acetylenic and steroidal alcohols could all be oxidised with dimethyl sulfoxide-oxalyl chloride in high yields under mild conditions. 

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