Synthesis of Polyenes. VI. Isoprenoid Polyenes Containing Sterically Hindered cis Configurations<sup>1</sup>

Oroshnik, William; Mebane, Alexander D.

doi:10.1021/ja01651a033

Cited by 48 publications

(13 citation statements)

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“…53) and the corresponding retinene 2 . Partial explanation has been offered by OROSHNIK et al (337,340,339), FARRAR et al (IIS) , and DALE (79). It has been proposed that the character of the fundamental band, indicating a moderately degraded spectrum, is caused by the spatial conflict between the gem.…”

Section: Cis-trans Isomerism and Spectramentioning

confidence: 99%

“…Soon after the same research group synthesized hindered cis isomers of several isoprenic dienes, trienes, tetraenes and pentaenes of the C 20 -series (339). KARRER et al were successful in synthesizing hindered cis forms of fJ-carotene, lycopene, and 1, 18-diphenyl-3,7,12,16-tetramethyl-octadecanonaene (P.104) (I06, I25, I26, I28, 287).…”

Section: ~mentioning

confidence: 99%

“…Although this statement is also valid in the diphenylhexatriene and diphenyloctatetraene sets (292, 522) (PP.I72, 177) it does not apply to dienes. Certain isoprenic, hindered cis dienes of the C 20 -series are resistant to iodirie while some unhindered cis isomers respond to the catalyst normally (339). In two polyene-azine sets (pp.…”

Section: Cis-fransmentioning

confidence: 99%

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Cis-trãns Isomeric Carotenoids Vitamins A and Arylpolyenes

Ƶechmeister¹

1962

324

272

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Section: Cis-trans Isomerism and Spectramentioning

confidence: 99%

Section: ~mentioning

confidence: 99%

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Cis-trãns Isomeric Carotenoids Vitamins A and Arylpolyenes

Ƶechmeister¹

1962

324

272

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“…A band at 780 cm-l in the infrared spectrum of X I confirmed the presence of a cis-disubstituted double bond. The shift t o the higher region indicated some conjugati6n with the cyclopropane ring 15). The n~olecular rotational change3 of alcohol VII and hydrocarbon X I was compared with that of the analogous compounds in the cholesteryl series (16).…”

Section: Hydrocarbonsmentioning

confidence: 99%

Steroids: Ix. The Solvolysis of 4,4-Diethylcholesteryl Methanesulfonate

Gupta¹,

Schilling²,

Just³

1965

Can. J. Chem.

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The acetol~sis of 4,4-diethylcholesteryl mesylate gave 11% 3,4-dialkyl (A), 39% 3a,5-cyclo (C), and 50% A-norcholestene (B) derivatives. The corresponding yield for the 4-4,dimethyl series is 25, < 11.6, and > 61.4%.Knowledge of the mechanism of solvolysis of cholesteryl derivatives does not permit one to predict with reasonable accuracy the solvolytic reactions of 4-monomethyl (2, 3) or 4,4-dimethyl (4, 5, 6) cholesteryl derivatives. Since small changes in structure seem to have a fairly large effect on the reactions, we undertook a study of the reactions of 4,4-diethylcholesteryl mesylate, expecting to obtain a product distribution similar to that observed in the solvolysis of 4,4-dimethylcholesteryl tosylate. In that reaction (6), one isolates products fornlally derived from carbonium ions A, B, and C in the yields indicated.Since the results obtained are somewhat unexpected, me would like to report on them.Cholest-4-en-3-one (7) was converted to 4,4-diethylcholest-5-en-3-one (11) by appropriately modifying the procedure described by Woodward, Barton, and co-workers (8). Lithium aluminium hydride reduction (8) of ketone I1 gave 4,4-diethylcholesterol (111) in quantitative yield. When ketone I1 \vas reduced with sodium borohydride in N,Ndimethylformamide (9) and the resulting inixture separated on alumina, there was obtained the starting material, 3a-alcohol IV, and 3p-alcohol I11 in 63.5, 1.2, and 15.1% yields respectively. The stereochemical assignment of the two epiineric alcohols was based on the relative yield of products obtained and the relative ease of elution on alumina (10).

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“…A valu e of 34 l it er s/ mole cm was used for t he mola l' a b s orp tivi t~ of t he t etraenes, based on a compa ri son of ba nd stre ngths for bands near 3.3 and 10.4 11-in the sp ectrum of t h e conj ugated tetrae ne compound des i~n a t e d 4, 5-11' ansXVla by Oroshnik and NIeb a ne [39] a nd t h e fa ct t h a t th e a bsorpti vit ies for t he 3 .3-11-ba nd for m a n y non aromati c hydrocarbons seem to average about 45 litcrs /mole cm as indica t ed by t he da t a of O ' Connor a nd Goldblat t [10 ]. The r es ults of t Il e calculat ions are given in table 2.…”

Section: Interpretation Of the Lo4-j-i Bandmentioning

confidence: 99%

Some changes in double-bond structure during the vulcanization of natural rubber

Linnig¹,

Parks²,

Stewart³

1964

J. RES. NATL. BUR. STAN. SECT. A.

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Near-infrared studies indicate the a bsence or n car-absence of isolated cis and te rminal double bonds in rubber vulcanized either with or without acccleraLors, as well as in t he squ alene-sulfur r eaction product. The usc of purifi ed n atu r al rubber indicates a Jl eW a bsorption near 6.1 J1-on r eaction with s ulfur, either with or without accelerators in t he ru bber system. This n ew a bsorption m ay be du e either to a dou ble bond with an attached sulfur atom or to conju gated dou ble-bond systems t hat do not r eact r eadily with maleic an h ydride. Ultraviolet spectra of chromatographi c fractions s how t hat s qu alen e that has r eacted with 15 p er ce nt of s ulfur contain s co nju gated trienes, tetraenes, and possibly dienes, hexaenes, and heptaenes. Th e conju gated dienes, t ri enes, and tetraen es arc probabl y present in suffi cient proportion s to accoun t for a s ignifi cant portion of the band at 10.4 J1-. There is some ev id ence that t he tri enes a nd tetrae nes, at least, m ay be largely all-trans in co nfi guration. Other contribu tor s to t he band at 10.4 J1-ar c poss ibly isolated, trans dou ble bonds and heterocyclic sulfur stru ctures alon g t he chain .

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Synthesis of Polyenes. VI. Isoprenoid Polyenes Containing Sterically Hindered cis Configurations¹

Cited by 48 publications

References 0 publications

Cis-trãns Isomeric Carotenoids Vitamins A and Arylpolyenes

Cis-trãns Isomeric Carotenoids Vitamins A and Arylpolyenes

Steroids: Ix. The Solvolysis of 4,4-Diethylcholesteryl Methanesulfonate

Some changes in double-bond structure during the vulcanization of natural rubber

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Synthesis of Polyenes. VI. Isoprenoid Polyenes Containing Sterically Hindered cis Configurations1

Cited by 48 publications

References 0 publications

Cis-trãns Isomeric Carotenoids Vitamins A and Arylpolyenes

Cis-trãns Isomeric Carotenoids Vitamins A and Arylpolyenes

Steroids: Ix. The Solvolysis of 4,4-Diethylcholesteryl Methanesulfonate

Some changes in double-bond structure during the vulcanization of natural rubber

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Product

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Synthesis of Polyenes. VI. Isoprenoid Polyenes Containing Sterically Hindered cis Configurations¹