Synthesis and stereochemistry of hydrogenated 1,1,4,4,7a-pentamethylindenes

1980 ◽  
Vol 58 (17) ◽  
pp. 1810-1820 ◽  
Author(s):  
Alan Francis Thomas ◽  
Michel Ozainne ◽  
Renée Guntz-Dubini
Keyword(s):  
Double Bond ◽  
Cyclohexane Ring ◽  
Wittig Reactions

Ease of methylation of hydrogenated 2H-inden-2-ones depends on the presence of a double bond in the cyclohexane ring, and occurs readily with compound 20 but not with 10. Differences of reactivity are also noted in Wittig reactions. Most reactions of the system are highly stereoselective, and the stereochemistry of hydrogenated indenes is discussed.

scholarly journals A minimal structural variation can overcome tumour resistance of oxaliplatin: the case of 4,5-dehydrogenation of the cyclohexane ring

RSC Advances ◽  
2019 ◽  
Vol 9 (56) ◽  
pp. 32448-32452 ◽  
Author(s):  
Paride Papadia ◽  
Valentina Gandin ◽  
Alessandra Barbanente ◽  
Alessandro G. Ruello ◽  
Cristina Marzano ◽  
...  
Keyword(s):  
Double Bond ◽  
Structural Variation ◽  
Cyclohexane Ring ◽  
Anticancer Compounds ◽  
New Family

A new family of anticancer compounds has been derived from oxaliplatin by inserting a double-bond between carbons 4 and 5 of the 1,2-diaminocyclohexane ring.

scholarly journals (2S,4S)-2-[(S,E)-2-Bromo-1-nitromethyl-3-phenylallyl]-4-methylcyclohexanone

2012 ◽  
Vol 68 (4) ◽  
pp. o1253-o1253
Author(s):  
Long Zhao ◽  
Chao Wu ◽  
Wen-Zeng Weng ◽  
Chu-Xia Yan ◽  
Ai-Bao Xia
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Chair Conformation ◽  
Cyclohexane Ring ◽  
Chiral Centers

The crystal structure of the title compoud, C17H20BrNO3, contains three chiral centers, which all exhibit anSconfiguration. The C=C double bond has anEconformation. The cyclohexane ring is in a chair conformation. In the crystal, molecules are linked by weak N—O...Br interactions [O...Br = 3.136 (4) Å].

scholarly journals Crystal structure of a bioactive sesquiterpene isolated fromArtemisia reticulata

2016 ◽  
Vol 72 (4) ◽  
pp. 460-462
Author(s):  
A. K. Bauri ◽  
Sabine Foro ◽  
Nhu Quynh Nguyen Do
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Hydrogen Bonds ◽  
Silica Gel ◽  
Title Compound ◽  
Chair Conformation ◽  
Cyclohexane Ring ◽  
Exocyclic Double Bond ◽  
Compound C ◽  
Cyclopentane Ring

The title compound, C15H24O2{systematic name: 1-[6-hydroxy-7-(propan-2-yl)-4-methylidene-2,3,3a,4,5,6,7,7a-octahydro-1H-inden-1-yl]ethanone} was isolated fromA. reticulataby column chromatography over silica gel by gradient solvent elution. The molecule comprises a bicyclo[4.3.0]nonane ring bearing acetoxy, hydroxy and isopropyl substituents, and an exocyclic double bond on the cyclohexane ring. In the bicyclic skeleton, the cyclohexane ring adopts a chair conformation ring and the cyclopentane ring is in an envelope conformation. In the crystal, molecules are linked by O—H...O hydrogen bonds, forming chains along [010]. These chains are cross-linked by C—H...O hydrogen bonds.

The stereochemistry of the Wittig reactions of allylic phosphoranes and phosphonate esters with aldehydes

1977 ◽  
Vol 55 (7) ◽  
pp. 1218-1228 ◽  
Author(s):  
Richard Neville Gedye ◽  
Kenneth Charles Westaway ◽  
Parkash Arora ◽  
Robert Bisson ◽  
Aly Hamdy Khalil
Keyword(s):  
Double Bond ◽  
Main Product ◽  
Triethyl Phosphite ◽  
Geometric Isomer ◽  
Major Product ◽  
General Mechanism ◽  
Phosphonium Salts ◽  
Phosphonate Esters ◽  
Wittig Reactions

Methyl Z- and E-4-bromo-3-methylbut-2-enoate 13 and 14 react with triethyl phosphite stereospecifically with retention of configuration to give the corresponding Z- and E-phospho-nate esters 8 and 9. The Z- and E-phosphonates react with aldehydes with extensive stereomutation of the double bond. Rapid equilibration to a mixture of one part E-phosphonate to two parts Z-phosphonate occurs when either geometric isomer is treated with base. Despite this, the E-2,E-4 ester 16 is the chief product of the reaction. Methyl E-β-ionylideneacetate 16b is the major product of the reaction of either isomer with β-cyclocitral and with cyclohexene car-boxaldehyde only the E-2,E-4 isomer 16c is formed. Benzaldehyde reacts with the phosphonates to give a mixture of the E-2,E-4 and Z-2,E-4 isomers 16a and 15a in a 4:1 ratio. Although the corresponding Z- and E-phosphonium salts 6 and 7, obtained stereospecifically from the bromo esters, react by the same general mechanism as the phosphonates the main product with benzaldehyde is the Z-2,Z-4 isomer 17a.

The synthesis of 5-Alkylidenefuran-2(5H)-ones

1981 ◽  
Vol 34 (8) ◽  
pp. 1745 ◽  
Author(s):  
PJ Babidge ◽  
RA Massy-Westropp
Keyword(s):  
Carbon Monoxide ◽  
Double Bond ◽  
Raney Nickel ◽  
Reaction Proceeds ◽  
Desulfurization Process ◽  
Cyclic Anhydrides ◽  
Wittig Reactions

5-Alkylidenefuran-2(5H)-ones can be synthesized efficiently from S- methyl 5-oxo-2,5-dihydro-furanylidenealkanethioates by treatment with Raney nickel. The ylidenealkanethioates are prepared from the Wittig reactions between cyclic anhydrides and (methylthio)carbonylmethylenetriphenyl-phosphorane or its alkylated derivative. The decarbonylation-desulfurization process proceeds largely with retention of configuration about the double bond. It is considered that the reaction proceeds by loss of carbon monoxide to give a thioenol ether which is subsequently hydrogenolysed to the 5- alkylidenefuran-2(5H)-one.

scholarly journals Crystal structure of (E)-2-[3-(tert-butyl)-2-hydroxybenzylidene]-N-cyclohexylhydrazine-1-carbothioamide

2018 ◽  
Vol 74 (10) ◽  
pp. 1460-1462 ◽  
Author(s):  
Md. Azharul Arafath ◽  
Huey Chong Kwong ◽  
Farook Adam ◽  
Mohd. R. Razali
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Title Compound ◽  
Chair Conformation ◽  
Cyclohexane Ring ◽  
Compound C ◽  
Similar Conformation ◽  
Ring Motif

In the title compound, C18H27N3OS, the cyclohexane ring has a chair conformation. The azomethine C=N double bond has an E configuration. The nearly planar hydrazinecarbothioamide moiety and substituted benzene ring are twisted by 31.13 (5)° relative to each other. The amide moiety and the cyclohexane ring are almost perpendicular to each other; a similar conformation was previously observed in reported structures. In the crystal, molecules are linked by N—H...S hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif.

THE THYMOLYTIC ACTIVITY OF 6- AND 9-HALOCORTICOIDS AND RELATED STEROIDS

1965 ◽  
Vol 49 (2) ◽  
pp. 262-270 ◽  
Author(s):  
Ralph I. Dorfman ◽  
P. G. Holton ◽  
Fred A. Kind
Keyword(s):  
Double Bond ◽  
Subcutaneous Injection ◽  
Fluocinolone Acetonide ◽  
Relative Potency ◽  
Subcutaneous Route ◽  
Adrenalectomized Rats

ABSTRACT Adrenalectomized rats were used for the determination of the relative potency of various 6- and 9-halo substituted corticoids administered subcutaneously or by gavage using thymus weightas the endpoint. By subcutaneous injection, fluocinolone acetonide was the most active corticoid at 700 times that of cortisol. This compound was also the most active corticoid by the gavage route and was judged to be 570 times as active as the standard cortisol. The introduction of the 16,17-acetonide and 16,17-acetone 21-acetate groups into 17α,21-dihydroxy-9α,11β-dichloropregna-1,4-diene-3,20-dione increased the activity by a factor of 42 and 100, respectively. The introduction of the δ1 double bond into 6α-fluoroprogesterone 16,17-acetonide caused an increase of 10-fold in thymolytic activity assessed by the subcutaneous route

TRIGLYCERIDE COMPOSITION OF SIXTEEN STRAINS OF MARINE DIATOM

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Lily M.G. Panggabean ◽  
Abdullah Rasyid ◽  
Zarrah Duniani ◽  
Yana Meliana ◽  
Indah Kurniasih
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acid ◽  
Double Bond ◽  
Unsaturated Fatty Acid ◽  
Ion Trap ◽  
Carbon Chain ◽  
Highly Unsaturated Fatty Acid ◽  
Marine Diatom ◽  
Ion Trap Mass Spectrometry ◽  
Spectra Analysis

Trigliceride or triacylglicerol (TAG) composition in crude oil of sixteen strain of marine diatom has been detected by spectra analyses on an Electrospray - Ion Trap – Mass Spectrometry (ESI-IT-MS) HCT Bruker-Daltonic GmbH instrument with AgNO3 used as coordination ionization agent. Biomass samples of each microalga strain were taken from early and late stationary cultures in f/2 enriched seawater and algal oils were extracted according to Bligh and Dyer. Results from spectra analysis showed that P-Pt-P (C16:0-C16:1-C16:0) were distinguished in TAG from diatom strains Chaetoceros sp.1, Chaetoceros sp.2, Thalasiossira sp.1, Thalasiossira sp.2, Thalasiossira sp.3, Navicula sp. 1, Navicula sp. 2, Navicula sp. 3, Navicula sp. 4, Nitzschia sp. 2 and Amphora sp. In contrast, TAGs in Melosira sp. included P-P-P (C16:0-C16:0-C16:0) and P-P-O (C16:0-C16:0-C18:1) were identified. TAGs from Chaetoceros sp. were the most varies among samples, i.e. P-Pt-P (C16:0-C16:1-C16:0), A-P-M (C20:4-C16:0-C14:0), P-Pt-Lt (C16:0-C16:1-C18:3), P-Pt-A (C16:0-C16:1-C20:4), D-P-P (C22:6-C16:0-C16:0), A-Ln-P (C20:4-C18:2-C16:0). Various TAGs were also detected in Nitzschia sp.2, i.e. P-Pt-M (C16:0-C16:1-C14:0), P-Pt-P (C16:0-C16:1-C16:0), P-Pt-S (C16:0-C16:1-C18:0), P-Pt-A (C16:0-C16:1-C20:4). TAGs composition in Skeletonema strains that similar to those in Nitzschia sp.1 has longer carbon, i.e. P-P-O (C16:0-C16:0-C18:1), P-O-O (C16:0-C18:1-C18:1) and O-O-O (C18:1-C18:1-C18:1). TAGs with longer carbon chain and more double bond including highly unsaturated fatty acid C20:4 were increased with culture age in diatoms Chaetoceros sp.1, Chaetoceros sp.2, Thalasiossira sp.2, Navicula sp.1 and Nitzschia sp. 2.Keywords: diatom, TAG, ESI-IT-MS, f/2, early and late stationary

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