Diazomalonic acid esters

Thep-nitrophenyl ester of diazomalonic acid has been made. While this derivative proved useful for acylating the serine residues at the active sites of trypsin and chymotrypsin (e.g. Vaughan and Westheimer, 1969a,b ... 

Photolytic and catalytic decomposition of a-diazo esters produces )8-lactones, which are formed via intramolecular C—H insertion of a carbene or carbenoids. Tertiary alkyl esters of diazomalonic acid are decomposed by rhodium acetate with exclusive formation of the four-membered ring 211. This suggests a smooth insertion into the C—H bond activated by the adjacent oxygen atom (90TL1023). jS-Lactone 212 was obtained by photolysis of diazo malonic ester 213 (71CC577). 

The attempted synthesis of O-bridged compounds from mixed allyl esters of diazomalonic acid of the type 723, in which the olefinic chain is located at the diazo side of the molecule, has failed (93JOC4646). However, tethering the olefin moiety to the chain that links the carbonyl and diazocarbonyl functionalities provides a great variety of tricyclic-nonfused compounds (82T1477 92JA1874 94TL7159). The most representative examples are shown in Schemes 41 and 42. 

Following the method of Corey and Felix [12], Lowe studied the photolysis of the diazomalonic acid amide system. This modification is useful because it provides an ester substituent on the a-carbon of the 0-lactam ring a good target for further synthetic manipulations towards the desired amide substituent. From the first photolytic experiments of this system (114), both the cis (115) and... 

Nakaura and Ukita devised a simple indole synthesis from the Rh-catalyzed condensation of a-diazophospho-nates and o-acylanilines (Scheme 6, equation 1) [58]. Moody and colleagues combined diethyl diazomalonate and Af-alkylanilines in a Rh-catalyzed synthesis of indox-ylic acid esters (equation 2) [59], This chemistry represents a simple synthesis of these rare indoxyl-2-carboxylates. 

Di-fcr(-butyl diazomalonate Malonic acid, diazo-, di-(erf-butyl ester (8) Propanedioic acid, diazo-, bis(l,l-dimethylethyl)ester (9) (35207-75-1)... 

RHODIUM-CATALYZED HETEROCYCLOADOITION OF A DIAZOMALONATE AND A NITRILE SYNTHESIS OF 4-CARBOMETHOXY-5-METHOXY-2-PHENYL-1,3-OX AZOLE (4-Oxazolecarboxylic acid, 5-methoxy-2-phenyl-, methyl ester)... 

One approach to the rearrangement problem for carbenes has been partially solved with the use of ethyl 2-diazomalonyl esters which are not as susceptible to rearrangements as diazoacetates (Hexter and Westheimer 1971). Vaughan and Westheimer (1969) have prepared the nitrophenyl ester of ethyl 2-diazomalonate and used it to acylate the reactive serine of trypsin. Photolysis at 253 nm has yielded a glutamic acid residue which presumably arises from the insertion of the... 

Allyldiethylamine behaves similarly, but the yields are low since neither the starting amine nor the products are stable to the reaction conditions. For the efficiency of the cyclopropanation of the allylic systems under discussion, a comparison can be made between the triplet-sensitized photochemical reaction and the process carried out in the presence of copper or rhodium catalysts whereas with allyl halides and allyl ethers, the transition metal catalyzed reaction often produces higher yields (especially if tetraacetatodirhodium is used), the photochemical variant is the method of choice for allyl sulfides. The catalysts react with allyl sulfides (and with allyl selenides and allylamines, for that matter) exclusively via the ylide pathway (see Section 1.2.1.2.4.2.6.3.3. and Houben-Weyl, Vol. E19b, pll30). It should also be noted that the purely thermal decomposition of dimethyl diazomalonate in allyl sulfides produces no cyclopropane, but only the ylide-derived product in high yield.Very few cyclopropanes have been synthesized by photolysis of other diazocarbonyl compounds than a-diazo esters and a-diazo ketones, although this should not be impossible in several cases (e.g. a-diazo aldehydes, a-diazocarboxamides). Irradiation of a-diazo-a-(4-nitrophenyl)acetic acid in a mixture of 2-methylbut-2-ene and methanol gave mainly l-(4-nitrophenyl)-2,2,3-trimethylcyclo-propane-1-carboxylic acid (19, 71%) in addition to some O-H insertion product (10%). ... 

Reaction of 2,3-dihydro-1,4-dioxin with ethyl diazopyruvate over (trimethylphosphino)copper(I) chloride produces dihydrofuroic ester (114) and a similar reaction with dimethyl diazomalonate, followed by acid hydrolysis, afforded the lactone ester (115) <85JOC4681>. 

In addition to protonation, the six-membered ring can also be formed with Lewis acids, for example in the case of diazomalonic ester (2.268) by two equivalents of SbCl5. One antimony tetrachloride cation acts as a Lewis acid and the second as counter ion (SbClg"). Analogous salts are formed with boron trifluoride (2.269). 

In a model study, Helquist and co-workers described the reaction of dimethyl diazomalonate 128 with benzonitrile to prepare 5-methoxy-2-phenyl-4-oxazolecar-boxylic acid methyl ester 129 nearly quantitatively (Scheme 1.35). Several other 2-aryl-5-methoxy-4-oxazolecarboxylic acid methyl esters were prepared analogously. In addition, 2-aIkyl(aIkenyl)-5-methoxy-4-oxazolecarboxylic acid methyl esters were also prepared, although the yields for aliphatic nitriles were not as good, unless the nitrile was used as solvent. Other metal salts—including Rh2 (NHAc)4, Cu(OTf)2, Cu(C2Hs-acac)2, Rh2(02CC3H7)4, and Rh3(CO)ie— were not as effective as Rh2(OAc)4 in this reaction. 

Diazomalonate esters are generally poor substrates for this reaction and only moderate ees have been obtained so far in the rhodium-catalysed addition to alkenes. Far better results have been obtained using the phenyliodonium ylide generated from dimethylmalonate and also Meldrum s acid (9.34) and iodosylben-zene in the presence of the rhodium catalyst bearing ligand (9.35). ... 

Diazo compounds. Besides diazomethane and the Simmons-Smith reagent, diazocarbonyl compounds (diazomethylketones I), and particularly diazoesters (diazoacetates II, diazomalonates III and a-diazo 3-keto-esters IV) are widely used because they are versatile intermediates for further transformations (acids, alcohols,. ..). 

The AT-hydroxysuccinimide ester of ethyl diazomalonate is one of a number of succinimide esters that have been used selectively to acylate amino groups, e.g., the amino acid of charged tRNAs (see also Table VI) ... 

An alternative synthesis of the sulhlimine by reaction of the penicillin (383) with ethyl azidoformate resulted in the azetidinone (384) in low yield (Numata et al., 1972). This product was probably the result of an electrocyclic rearrangement of the intially formed sulfilimine (385). Conversion of 385 to a deacetoxycephem (290) was accomplished by heating in the presence of an acid catalyst. An analogous ring opening reaction was also observed on thermal treatment of the penicillin ester with dimethyl diazomalonate in the presence of cupric sulfate as catalyst. The initially formed ylide (386) proceeded to rearrange in an electrocyclic manner to afford the azetidinone (387) in good yield (Numata et al., 1972). 

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