The Synthesis of Unsaturated Fatty Acids. Synthesis of Oleic and Elaidic Acids

Noller, C. R.; Bannerot, R. A.

doi:10.1021/ja01322a033

Cited by 21 publications

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“…Materials. PMAH (2-[[ N -(aminoethyl)amino]methyl]-4-[ N -[2-(4-imidazolyl)ethyl]carbamoyl]-5-bromopyrimidine) was prepared as previously reported 21 with the following modifications: (1) the reaction of 5-bromo-2-(hydroxymethyl)-4-pyrimidinecarboxylic acid with thionyl chloride was carried out in the presence of a small amount (0.1−0.2 equiv) of pyridine to catalyze the decomposition of the chlorosulfinate − intermediate (in the absence of pyridine, the reaction can take other courses); (2) in the last step, 4 equiv of ethylenediamine, instead of 6, were added to the 2-(chloromethyl)-4-[2-(4-imidazolyl)ethyl]carbamoyl]-5-bromopyrimidine.…”

Section: Methodsmentioning

confidence: 99%

EPR Spectroscopic Reinvestigation of the Activation of Iron Complexes of PMAH as a Bleomycin Model

1998

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The structure and reactivity of iron complexes of PMAH, which contains ligands that mimic the metal binding domain of iron bleomycin (FeBLM), have been studied using EPR spectroscopy. It had been reported [Guajardo, R. J.; Hudson, S. E.; Brown, S. J.; Mascharak, P. K. J. Am. Chem. Soc. 1993, 115, 7971] that iron complexes of PMAH can be activated to a ferric hydroperoxide, a structural analog by activated BLM, by various routes, including reaction of [FeIIIPMA]2+ with iodosylbenzene (PhIO), methanol, and base. We show that with or without PhIO, the latter reaction produces the methoxide complex of FeIIIPMA, and not the hydroperoxide, contrary to the previous report. Thus, O−O bond formation through generation of a ferric hydroperoxide does not occur. The same methoxide complex (g = 2.28, 2.18, 1.93) is generated by the addition of organic base and CH3OH, or LiOCH3, to [FeIIIPMA]2+. The formation of this [CH3O−FeIIIPMA]+ complex is confirmed by EPR titration of [FeIIIPMA]2+ with -OCH3 and by electrospray mass spectrometry. In contrast, the hydroperoxy complex of FeIIIPMA (g = 2.22, 2.17, 1.94) can be generated by the reaction of [FeIIIPMA]2+ with hydrogen peroxide or during aerobic oxidation of [FeIIPMA]+. The present results illustrate that activation of iron complexes of PMAH occur under conditions that produce activated BLM and further demonstrate that reaction of [FeIIIPMA]2+ with PhIO and base does not provide a route to either a hypervalent iron species or a hydroperoxide intermediate. These results agree with the finding that PhIO cannot be used to generate activated bleomycin [Sam, J. W.; Tang, X.-J.; Magliozzo, R. S.; Peisach, J. J. Am. Chem. Soc. 1995, 117, 1012].

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Section: Methodsmentioning

confidence: 99%

EPR Spectroscopic Reinvestigation of the Activation of Iron Complexes of PMAH as a Bleomycin Model

1998

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“…The Hamonet synthesis of ethers from -haloalkyl ethers and an organomagnesium halide is a very general reaction, and is the only useful method for direct production of ethers from a Grignard reagent. This synthesis (see Section VI,A,2,(e)) has probably been the most common application of a-haloalkyl ethers (37,86,111,117,133,146,176,180,204,208,216,230,231,283,294,295,309,372,414). The reactions are smooth, and fairly good yields are usually obtained.…”

Section: Uses a As Intermediates In Organic Synthesismentioning

confidence: 97%

“…The groups R, R', or R" may be variously alkyl or aryl, and may contain substituents, as long as these are less reactive toward the Grignard reagent than is the a-halogen atom. Many examples of this type of reaction occur in the literature (37,42,46,86,111,117,133,146,180,204,208,216,222,223,230,231,257,283,295,309,319,372,385,388,389,414,423). Organolithium (390) and organozinc (163,237,239) derivatives cause analogous reactions, as do organosodium compounds (30,272), although in the latter case the yields reported are low.…”

Section: Ormentioning

confidence: 97%

The alpha-Haloalkyl Ethers

Summers¹

1955

Chem. Rev.

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“…Use of 2,3-dibromo compounds however, alters the situation (Tables 6 and 7), greatly improving the stereoselectivity for trans-alkylation. Thus formation of (28) involves 70-74% rrans-alkylation compared with predominating cis-when the 2,3-dichloro compounds are used; the same applies in the pyran series. The greater selectivity associated with the bromo series may be associated with the structure of the bromonium intermediates approximating to (25) and (27) as distinct from (23) and (24).…”

Section: CImentioning

confidence: 98%

β-Halogeno ether synthesis of olefinic alcohols: stereochemistry and conformation of 2-substituted 3-halogenotetrahydro-pyran and -furan precursors

Crombie¹,

Wyvill²

1985

J. Chem. Soc., Perkin Trans. 1

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Ring -scission of cis-or trans-2-al kyl-(or aryl-) 3-c hlorotetra hydropyrans proceeds regioselectively and highly stereoselectively to give (€)-alk-4-en-1 -ols, but in the parallel tetrahydrofuran series (Z)-/(€)mixtures, dependent on precursor geometry, are formed. In this paper the stereochemistry and conformation of the tetrahydro-pyran and -furan precursors are considered. The cisltrans-composition of 2,3-dihalogenotetrahydro-pyrans and -furans made by various routes is reported. Reaction with Grignard reagents gives separable cis-/trans-mixtures the stereoisomeric composition of which, in the cases examined, does not depend on the stereoisomeric composition of the dihalide, but does vary with the halogen and the composition of the Grignard or dialkylmagnesium; possible reasons are discussed.The stereochemistry and conformation of the 2-alkyl-(or aryl-)3-~hIorotetrahydropyrans is analysed by n.m.r. methods (JZa,3ecis ca. 1.5 Hz; J2a,3atrans ca. 9.8 Hz) but assignments for the two tetrahydrofuran series with JZ3 2.6-3.6 and 4.3-5.9 are made uncertain by pseudorotation. The stereochemical identity of the two series is rigorously proved by isolation of cis-and trans-2-allyl-3chlorotetrahydrofuran. On the one hand the former is hydrogenated to the cis-2-propyl compound, correlated with other members of the alkyl series, but on the other it is oxidised and the acid is converted into the cis-p-bromophenacyl ester. The stereochemistry and conformation of the latter is rigorously demonstrated by an X-ray structure.The stereochemistries and conformations of the 2-deuterio-and 2-methoxy-3-chlorotetrahydropyrans are discussed, and consideration is then extended to the 2-al kyl-3-chloro-2-methyltetra hydro-pyran and -furan series.p-Halogeno ether synthesis using tetrahydro-furans or -pyrans provides an excellent synthetic method for extending an alkyl or aryl residue by four or five carbon atoms in a straight chain containing a double bond (Scheme l).',2 The sequence proceeds A ) a:& ' -OH Scheme 1. b-Halogeno ether synthesis using tetrahydropyran and tetrahydrofuran derivatives. Reagents: i, RMgX; ii, Na; iii, hydrogena tion Table 1. Further cyclic P-halogeno ethers, and alcohols formed on ring scission with electropositive metals Halogeno ether QYu X Me GR Alcohol from ring-scission RCH=CH[CH,],OH R(Me)WH[CH ,] ,OH RCH=CHCH(Me)CH,OH R(Me)C=CH[CH,] ,OH RCH=C(Me)[CH,] ,OH RCH=CHCH( Me)[CH,

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The Synthesis of Unsaturated Fatty Acids. Synthesis of Oleic and Elaidic Acids

Cited by 21 publications

References 0 publications

EPR Spectroscopic Reinvestigation of the Activation of Iron Complexes of PMAH as a Bleomycin Model

EPR Spectroscopic Reinvestigation of the Activation of Iron Complexes of PMAH as a Bleomycin Model

The alpha-Haloalkyl Ethers

β-Halogeno ether synthesis of olefinic alcohols: stereochemistry and conformation of 2-substituted 3-halogenotetrahydro-pyran and -furan precursors

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