Nuclear Magnetic Resonance Determination of Substituent Methyls in Fatty Acids<sup>1</sup>

Cason, James; Lange, Gordon L.

doi:10.1021/jo01030a567

Cited by 18 publications

(2 citation statements)

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“…and exalnination by n.m.r. spectroscopy showed that the principal components were saturated, straight chain compounds (25). Chromatography on a silver nitrate -silicic acid column (26) gave only a small fraction (4% of total hydrocarbons) which appeared (by n.1n.r.)…”

Section: Deterniirzation Of Structure Of Components Of W a Smentioning

confidence: 99%

Composition of the leaf wax of Little Club wheat

Tulloch¹,

Weenink²

1969

Can. J. Chem.

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Leaf wax of Little Club wheat is composed of: hydrocarbons (8-15%); esters (2&26%); alcohols (2542 %); acids (2 %); P-diketone (&lo%); hydroxy !3-diketones (9-16 %); and unidentified material (9-12 %). The esters are mainly octacosanol esters of CI, to C32 fatty acids but lesser amounts of esters of trans 2-tetracosenoic and trans 2-docosenoic acids also occur. The free alcohols are almost entirely octacosanol. The P-diketone is hentriacontane-14,16-dione and the hydroxy-P-diketones are a 1 :1 mixture of 8-and 9-hydroxyhentriacontane-14,lG-diones.

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Section: Deterniirzation Of Structure Of Components Of W a Smentioning

confidence: 99%

Composition of the leaf wax of Little Club wheat

Tulloch¹,

Weenink²

1969

Can. J. Chem.

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“…This distinctiveness is supported by the broad antimicrobial spectrum of EM49 relative to those of the polymyxins and especially by the lack of cross-resistance between EM49 and polymyxin B1,2). (2), methyl 3(R)-hydroxydecanoate (3), and methyl 8(S)-methyl-3(R)-hydroxydecanoate (4).…”

mentioning

confidence: 99%

EM49, a new peptide antibiotic. IV. The structure of EM49.

Parker

Rathnum

1975

J. Antibiot.

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β‐Methyl‐verzweigte α.β‐ungesättigte Carbonsäuren durch nucleophile Addition von β‐Dicarbonylverbindungen an monosubstituierte Acetylene

1972

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Sowohl Brommalonsaure-diathylester (1 a) und Phenylacetylen (3a) als auch Malonsaurediathylester (8a) und 2-Brom-1-phenyl-acetylen (7a) setzen sich in Gegenwart von Zink in Xylol unter nucleophiler Addition des intermedilr entstehenden Zink-monobromid-malonsaure-diathylesters (2a) iiber die Zwischenstufen 4a und 5 a zum p-Methyl-a-athoxycarbonylzimtsaure-athylester (6a) urn, aus dem durch Verseifung und Decarboxylierung die P-Methylzimtsaure zu erhalten ist. Wird anstelle von Malonester Methylrnalons~ure-diathylester (8b) eingesetzt, so bleibt die Reaktion auf der Stufe des Buten-(3)-saureesters 5b stehen. Als Nebenprodukt entsteht dabei der Butin-(3)-saureester 9 b. Als P-Dicarbonyl-Komponente konnen Acetessigsaure-oder Benzoylessigsaure-iithylester, auch Acetylaceton eingesetzt werden, jedoch nehmen die Ausbeuten mit deren steigendem Enolgehalt ab. Aus 1-Alkinen (13) entsteht mit l a das Additionsprodukt 15, aus dem nach Verseifung und Decarboxylierung 3-Methyl-alkensauren in den drei isomeren Formen 17, 18 und 19 entstehen, ein weiteres Beispiel fur Drei-Kohlenstoff-Prototropie. p-Methyl Branched a.p-Unsaturated Carboxylic Acids by Nucleophilic Addition of p-Dicarbonyl Compounds to Monosubstituted Acetylenes l)Reaction of diethyl bromomalonate (la) with phenylacetylene (3a) as well as reaction of diethyl malonate (8a) with 1-bromo-2-phenylacetylene (7a) in the presence of zinc in xylene involves nucleophilic addition of the zinc monobromide of diethyl malonate (2a), formed as an intermediate via 4a and 5a, to yield P-methyl-a-(ethoxycarbonyl)cinnamic acid diethyl ester (6a), which on saponification and decarboxylation affords P-methylcinnamic acid.If the malonate is replaced by diethyl methylmalonate (Sb), the reaction stops at the stage of 3-butenoic acid ester 5b. In this reaction 3-butynoic acid ester 9b is formed as a by-product. The analogous reaction is given by ethyl acetoacetate, ethyl benzoylacetate and acetylacetone; the yields decrease with increasing enol content of the P-dicarbonyl compounds. The addition product 15 obtained by the reaction of 1-alkynes (13) with l a yields on saponification and decarboxylation 3-methylalkenoic acids. The latter occur in the three isomeric forms 17, 18 and 19, presenting another example of a three-carbon prototropy.Die aktivierte Dreifachbindung geht bekanntlich leicht nucleophile Additionsreaktionen ein. So lassen sich z. B. Alkyllithium-Verbindungen und anionisierte p-Dicarbonylverbindungen anlagern, nicht aber Grignard-Verbindungen 2). Es war naheliegend, die Reaktion von monohalogensubstituierten P-Dicarbonylverbindungen unter den Bedingungen der Reformatsky-Reaktion mit der aktivierten Acetylenbindung zu 1) Teil der Dissertation J. Feldkamp, Univ. Munster 1970.2 ) F. Bohlmann, Angew. Chem. 69, 82 (1957).

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Nuclear Magnetic Resonance Determination of Substituent Methyls in Fatty Acids¹

Cited by 18 publications

References 1 publication

Composition of the leaf wax of Little Club wheat

Composition of the leaf wax of Little Club wheat

EM49, a new peptide antibiotic. IV. The structure of EM49.

β‐Methyl‐verzweigte α.β‐ungesättigte Carbonsäuren durch nucleophile Addition von β‐Dicarbonylverbindungen an monosubstituierte Acetylene

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Nuclear Magnetic Resonance Determination of Substituent Methyls in Fatty Acids1

Cited by 18 publications

References 1 publication

Composition of the leaf wax of Little Club wheat

Composition of the leaf wax of Little Club wheat

EM49, a new peptide antibiotic. IV. The structure of EM49.

β‐Methyl‐verzweigte α.β‐ungesättigte Carbonsäuren durch nucleophile Addition von β‐Dicarbonylverbindungen an monosubstituierte Acetylene

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Nuclear Magnetic Resonance Determination of Substituent Methyls in Fatty Acids¹