Diethyl azodicarboxylate with

The [4 + 2] cycloaddition reaction of dibenzyl azodicarboxylate and glycals allows the stereoselective introduction of an amino group at the C-2 of a carbohydrate, the key step in the reaction is shown in Equation (1) <89JA2295>. The nature of the products was determined by x-ray crystallography NMR and IR data proved insufficient as the two possible products from [4 4- 2] and [2 + 2] addition are so similar. X-ray analysis confirmed that the reaction of diethyl azodicarboxylate with cyclopropylfuran gives compound (4), by a [4 4- 2] addition, in 94% yield. Further comparison of the NMR and IR data for all the adducts with spectral data of compound (4) confirmed that [4 + 2] adducts were formed consistently. 

The reaction of diethyl azodicarboxylate with cyclopentadiene reported by Diels in 1925 is of historical significance since it is one of the first examples of a Diels-Alder [4 2] cycloaddition (equation... 

The Diels-Alder reaction of diethyl azodicarboxylate with a 20-acetoxypregna-16,20-d iene (116) gave the heterocyclic der i vati ves (117 predominantly 16a), which were hydrolysed to the corresponding ketones (118). ... 

Triazinones (147) were synthesized by the cyclocondensation of the A-carbamoylguandine hydrochloride with an orthoester in DMF at 100°C (Equation (25)) <90CZP269077>. Triazinones (147) are also available (51-93%) from biguanides and diethyl azodicarboxylate with an improvement in yield compared with the use of ethylene carbonate (47%) <90JHC1213>. 

Likewise, the major product (amongst many), from the addition of diethyl azodicarboxylate with 1-methyl-2-vinylpyrrole has been shown, mainly on the basis of H and C NMR spectral evidence, to be the 2-ethoxy-6-(l-methylpyrrol-2-yl)-5,6-dihydro-4//-l,3,4-oxadiazine (263) <85JCR(S)12>,... 

A kinetic study of the nitrosation, at C-3, of the indolizine (764) and of its nitration, which occurs at C-4, has been presented.The reaction of diethyl azodicarboxylate with 2-methylindolizine yields a mixture of the mono-adduct (765 R = H) and the di-adduct [765 R = N(C02Et)NHC02Et]. "" The novel zwitterion (767 Ar = P-CIC6H4) is formed by the action of chlorobenzene-p-sulphonyl azide on the cyclohexenoindolizine (766). A stable carbo-selenaldehyde (768) has been obtained by treatment of 2,7-dimethylindolizine with the dimethylformamide-phosphorus oxychloride complex followed by sodium hydrogen selenide. ... 

Brimble, M.A. and Heathcock, C.H., Allylic amination by the Lewis-acid-mediated ene reaction of diethyl azodicarboxylate with alkenes, /. Org. Chem., 1993, 58(19), 5261-5263. 

Competition Between Ene and Diels-Alder Reactions. One area of considerable research centers on the reactivity of diethyl azodicarboxylate with conjugated dienes, systems in which two pericyclic reaction pathways are possible Diels-Alder and ene. Although a number of researchers have investigated this area, no clear explanation for the preference of one pathway over another has emerged. In most cases, one reaction course seems to be strongly predominant. At this time, only generalizations are possible. 

To prepare fervenulin 4-oxides 12 or toxoflavine 4-oxides 146, it is convenient to use the reaction of l,3-dimethyl-2,4-dioxopyrimidin-6-yl hydrazone 147 or N-(3-methyl-2,4-dioxopyiimidin-6-yl) iV-methylhydrazone 148 with potassium nitrate in acetic acid [75CPB1885,76CPB338,76JCS(CC)658,82JHC1309,93CPB362]. Diethyl azodicarboxylate can be used instead of potassium nitrate [76JCS(P1 )713]. 

In an initial step triphenylphosphine adds to diethyl azodicarboxylate 5 to give the zwitterionic adduct 6, which is protonated by the carboxylic acid 2 to give intermediate salt 7. The alcohol reacts with 7 to the alkoxyphosphonium salt 8 and the hydrazine derivative 9, and is thus activated for a SN2-reaction ... 

The conversion of an alcohol to an amine can be achieved in a one-pot reaction the alcohol 1 is treated with hydrazoic azid (HN3), excess triphenylphosphine and diethyl azodicarboxylate (DEAD). The initial Mitsunobu product, the azide 14, further reacts with excess triphenylphosphine to give an iminophosphorane 15. Subsequent hydrolytic cleavage of 15 yields the amine—e.g. as hydrochloride 16 ... 

The Mitsunobu reaction was also applied to the synthesis of [ 1,2,4]triaz-ino[4,5-n]indoles (84AG517). Thus, reaction of the 2-acylindoles 127 with sodium borohydride in methanol or with lithium aluminium hydride in tetrahydrofuran gave the corresponding alcohols 128. Their cyclization with diethyl azodicarboxylate in the presence of triphenyl-phosphine gave the triazinoindoles 129. Acid treatment of the latter afforded 130 (Scheme 30). 

Treatment of 6-arylidenehydrazino-3-alkyl-5-nitrouracils 510 with etha-nolic KOH caused a benzylic acid type of rearrangement to give 511, which were alkylated to give 512, whose cyclization with diethyl azodicar-boxylate gave (80H1295) 513 by intramolecular cycloaddition through valence isomerization and then aromatization with diethyl azodicarboxylate (Scheme 107). 

Cydization of P-hydroxy-a-amino esters under Mitsunobu reaction conditions is an alternative approach to aziridine-2-carboxylic esters [6b, 13-16], In this case the P-hydroxy group is activated by a phosphorus reagent. Treatment of Boc-a-Me-D-Ser-OMe 13 (Scheme 3.5) with triphenylphosphine and diethyl azodicarboxylate (DEAD), for example, gave a-methyl aziridinecarboxylic acid methyl ester 14 in 85% yield [15]. In addition to PPh3/DEAD [13b, 15], several other reagent combi-... 

Rzdtc) ] reacts with diethyl azodicarboxylate, azobenzene, or dimethyl acetylenedicarboxylate to give the appropriate hydrazine and disulfide... 

Unsymmetrical disulfides can be prepared by treatment of a thiol RSH with diethyl azodicarboxylate (EtOOCN=NCOOEt) to give an adduct, to which another thiol R SH is then added, producing the disulfide RSSR. ... 

Mercaptans have been oxidized with diethyl azodicarboxylate and triphenylphosphine. It is suggested that the formation of a charge-transfer complex (57) may be a key step in the reaction. 

Pavan Kumar et al. <2006NJC717> investigated the reaction of diethyl azodicarboxylate (DEAD) or diisopropyl azodicarboxylate (DIAD) with cyclic phosphates or phosphoramides in order to determine the structural preferences in spirocyclic penta- and hexacoordinate aminophosphoranes. They found that sulfur would coordinate to phosphorus to form the [3.3.0] bicyclic compounds 94-96. 

Thieno[2,3(3,2)-/]indolizines such as 50 undergo Diels-Alder reactions with diethyl azodicarboxylate (DEAD) to give the tetracyclic system 51 (Equation 6) <1995TL83>. 

Nagamatsu and Yamasaki synthesized the dihydrohexaaza-r-indacenone structure 197 via a diethyl azodicarboxylate-mediated cyclization of 196 with a range of aldehydes in good yield (Equation 50) <1995CC2041>. 

Acyclic ADC compounds, which are more correctly named as derivatives of diazene, are generally prepared from hydrazine derivatives. For example, diethyl azodicarboxylate (Chemical Abstracts name diethyl diazene-1,2-dicarboxylate)5 is prepared from hydrazine by treatment with ethyl chloro-formate followed by oxidation with chlorine in benzene-water.6 Other oxidants which have been used include JV-bromosuccinimide,7 nitric acid,8 inorganic nitrates,9 potassium dichromate,10 silver carbonate on celite,11 and phenyl iodosotrifluoroacetate.12 The hydrazine derivative may also be... 

Jimenez et al. studied the asymmetric Diels-Alder reactions of 1-aryl-1,2-diaza-l,3-butadienes 114, heterodienes derived from sugars, with diethyl azodicarboxylate (115), a heterodienophile [85]. The reactions were performed without solvent in a focused microwave reactor for periods of a few hours. The reaction is stereoselective... 

The 3-methyl- and 3-phenyl-l,2,3-oxadiazolinium salts 96 and 97 are capable of oxidizing thiols to disulfides <1995MI817>. New dihydro-1,2,3-benzoxadiazoles, prepared by the reaction of 1,2-benzoquinones with diethyl azodicarboxylate (DEAD) or diisopropyl azodicarboxylate (DIAD) in the presence of triphenylphosphine (Section 5.03.9.4), have been shown to undergo catalytic hydrogenolysis to give phenols (Equation 12) <20050L5139>. 

Ylides forming from the thermolysis of compound 59 (R1, R2 = Me, R3 = Ar, R4 = OMe) reacted also with dimethyl acetylenedicarboxylate (DMAD) or diethyl azodicarboxylate (DEAD) <2003TL5029> in the presence of aldehydes, quinones <2001TL2043>, or ketones <20020L2821, 20000L3501> to give 2,5-dihydrofuran derivatives, for example, 67 (Rs = Me, Et). 

The reactivity of compound 113 toward reactive linear and cyclic dienophiles was reported in a study directed to find a model systems for the proposed [4+2] cycloaddition in the biosynthesis of the natural products brevianamides, paraherquamides, and marcfortines. With DMAD and diethyl azodicarboxylate the formation of 114 and 115 was almost quantitative after 48 h at 80 °C (Cbz = Carbobenzyloxygroup). When relatively unreactive dienophiles such as cyclopentene and cyclohexene were used, harsh reaction conditions and/or a Lewis acid catalyst are necessary for the formation of 116a and 116b (Scheme 16). In contrast, the analogous intramolecular reaction carried out on compound 117 takes place within a few hours at room temperature, even in the absence of a Lewis acid catalyst, to give 118 in 42% yield (Scheme 16) <2000T6345>. 

Treatment of the cyclic ketene aminal 267 with diethyl azodicarboxylate results in formation of the reduced ring system 268 (Equation 52), probably via an initial aza-ene reaction, followed by fragmentation and ring closure <2002T7791>. 

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