Diethyl azodicarboxylate, reactions with

Diethyl azelate, 45, 31 Diethyl azodicarboxylate, reaction with cyclopentadiene, 49,1 Diethylbenzene as solvent for decomposition of diphenyIiodonium-2-carboxylate in preparation of... 

Additionally, uracil 6-iminophosphorane, isocyanate, and o-methyl-e-caprolactim ether join to form the intensely yellow pyrimido[4 5 4,5] pyrimido[6,l-n]azepine (360), as shown in Scheme 130. Upon ring closure, methanol is spontaneously eliminated. Diethyl azodicarboxylate affords with the other components pyrimido[4,5-e][l,2,4]triazoline (361), which is closely related to the alkaloid isofervenuline. The imidazo[5, -/][ ,2,4]tria-zine (362) results in a known Michael-type rearrangement sequence by treatment with diethyl acetylenedicarboxylate (86JOC149, 86JOC2787) in this latter case, the Michael-type addition occurs much faster than the expected three-component reaction [93H(35)1055]. 

Oxidation of hydrazines to diazines. Propargylic hydrazines are oxidized rapidly and efficiently in CH3OH at 0° by 4-methyl-l,2,4-triazoline-3,5-dione (MTAD) or diethyl azodicarboxylate (DEAD) with evolution of nitrogen to provide the corresponding allenes in 50-70% yield. The reaction occurs with high stereospecificity, and can be used to obtain optically active allenes (equation I).1... 

The substituted imidazolo[5,l-c] 1,2,4-triazole (70) has been obtained (68JOC1097) by the reaction of diethyl azodicarboxylate (69) with the strained bicyclic imidazolidine 68. 

Alternatively, the 5,6-double bond in the initial adduct can be elaborated via Diels-Alder reactions with cyclopentadiene derivatives and this provides an entry to the tetracy-clo[5.2.1.0 0 ]decane series. Hence reaction of the diethyl azodicarboxylate adduct with hexachlorocyclopentadiene gave the adduct 13 which was elaborated to give endo,syn-l,7,8,9,10,10-hexachlorotetracyclo[5.2.1.0 0 ]dec-8-ene (14). Similar syntheses yield derivatives with a variety of substituents at CIO and in this series it was found that sulfuric acid hydrolysis of the carbamates gave a better yield than sodium hydroxide in methanol. The... 

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). 

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-... 

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>. 

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>. 

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>. 

The ene reaction with diethyl azodicarboxylate has been used for removing unreacted allylstannanes from solution.298... 

A solution of phenylaminomethylenemalonate (1485) in THF was added to a solution of triphenylphosphine and diethyl azodicarboxylate in THF at -20°C. The reaction mixture was warmed to room temperature, diluted with water, and extracted with ethyl acetate to give methylenemalonate (1486) in 75-99% yields (87USP4636506). 

In a 1-1., three-necked, round-bottomed flask equipped with a constant-pressure dropping funnel, a mechanical stirrer, and a reflux condenser is placed 174 g. (1.0 mole) of ethyl azodicarbox-ylate in 150 ml. of ether. Freshly prepared cyclopentadiene (70 g., 1.06 moles) is added dropwise over a 1-hour period to the stirred ethereal solution of diethyl azodicarboxylate. During the addition a gentle reflux is maintained by external cooling with an ice-water bath as needed. When the addition is complete, the reaction mixture is allowed to stand for 4 hours, or less if the yellow color of the azodicarboxylic acid ester disappears. I he dropping funnel and condenser are replaced by a glass stoj)pcr and a short distillation head, respectively. The ether and unreactcd diene are distilled off on a steam bath and the... 

The bioreduction of carbonyl compounds with reductases has been exploited for many years, especially in the case of ketones, with baker s yeast Saccharomyces cerevisiae) being the most popular biocatalyst [45]. For instance, yeast treatment of 3-chloropropiophenone affords the expected (lS)-3-chloro-l-phenylpropan-l-ol, which was treated with trifluorocresol in tertrahydrofuran in the presence of tri-phenylphosphine and diethyl azodicarboxylate at room temperature to give (3R)-l-chloro-3-phenyl-3-[4-(trifluoromethyl)phenoxy]propane and the later reaction with methylamine leads to (R)-fluoxetine that is an important serotonin uptake inhibitor (Scheme 10.19) [46]. 

A very mild procedure for converting alcohols to iodides uses triphenylphosphine, diethyl azodicarboxylate (DEAD) and methyl iodide.24 This reaction occurs with clean inversion of stereochemistry.25 26 The key intermediate is again an alkoxyphosphonium ion. 

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