Studies on the Lignin of Eucalyptus regnans. II. The Nature of the Hydroxyl Groups and the Presence of the Carbonyl Group in Thiolignin

1948 ◽  
Vol 1 (2) ◽  
pp. 241
Author(s):  
JWT Merewether
Keyword(s):  
Benzoyl Chloride ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Eucalyptus Regnans ◽  
Trimethyl Ether ◽  
Free Hydroxyl ◽  
Active Methylene ◽  
Methylene Group ◽  
Alcoholic Hydroxyl

E. regnans thiolignin reacts with p-toluenesulphonyl chloride in pyridine to form a hexatosyl derivative ; its trimethyl ether reacts likewise to form a tritosyl derivative. Both compounds still have a free hydroxyl group which can be acetylated. Similarly they yield a hexabenzoate and tribenzoate respectively by the Schotten-Baumann reaction, but in pyridine, thiolignin reacts with benzoyl chloride to give a heptabenzoate and trimethylthiolignin a tetrabenzoate. No reaction takes place when trimethyl thiolignin is treated with triphenylchloromethane in pyridine. The above data are interpreted as evidence that of the four alcoholic hydroxyl groups three are secondary and one tertiary. With phenylhydrazine, thiolignin yields a phenylosazone ; with p-nitrophenylhydrazine it yields a p-nitrophenylhydrazone. On the other hand, trimethylthiolignin does not react with phenylhydrazine, indicating the absence of non-enolizable carbonyl groups. Thiolignin condenses with benzaldehydes indicating the presence of an active methylene group. From this evidence it is deduced that the grouping CH2-CO-CHOH- is present.

Studies on the Lignin of Eucalyptus regnans. IV. Alkali Lignin

1949 ◽  
Vol 2 (4) ◽  
pp. 600
Author(s):  
JWT Merewether
Keyword(s):  
Empirical Formula ◽  
Black Liquor ◽  
Hydroxyl Groups ◽  
Eucalyptus Regnans ◽  
Alkali Lignin ◽  
Active Methylene ◽  
Methylene Group ◽  
Alcoholic Hydroxyl ◽  
Soluble Alkali

By pulping Eucalyptus regnans using the soda process and acidifying the black liquor a crude alkali lignin has been isolated. This has been separated into two fractions, dioxan-ether insoluble alkali lignin-A and dioxan-ether soluble alkali lignin-B. A series of derivatives has been made from each. The data for alkali lignin-A are consistent with the empirical formula C68H78O27, containing nine methoxyl. groups, three acidic, and four alcoholic hydroxyl groups, one of which is tertiary, one carbonyl, and one active methylene group. Alkali lignin-B has been found to be identical with the alkali lignin previously isolated from sulphate black liquor.

Bisquaternary ammonium salts derived from 3α,12α-Diamino-5β-cholane and 3α,12α-Diamino-24-nor-5β-cholane

1971 ◽  
Vol 24 (3) ◽  
pp. 521 ◽  
Author(s):  
S Ahmed ◽  
M Alauddin ◽  
B Caddy ◽  
M Martin-Smith ◽  
WTL Sidwell ◽  
...  
Keyword(s):  
Deoxycholic Acid ◽  
Ammonium Salts ◽  
Hydroxyl Group ◽  
Amino Compound ◽  
Hydroxyl Groups ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Polyhydric Alcohols ◽  
Methane Sulphonate ◽  
Methylene Group

The preparation of 3α,12α-bisdimethylamino-5β-cholane dimethiodide, 3α,12α-bisdimethylamino-5β-cholane dimethiodide, 3α,12α- bisdimethylamino-24-nor-5β-cholanedimethiodide, and 3α,12α- bisdimethylamino-24-nor-5β-cholanediethiodide, from deoxycholic acid are described. During this work it was found that attempted copper- quinoline decarboxylation of dehydrocholic acid gives rise to lactol formation, and that what had previously been considered to be 3α,12α- dihydroxy-5β-cholane is a mixture of this compound and 12α,24- dihydroxy-5β-cholane. Comparable selectivity of attack by methanesulphonyl chloride and toluene-p-sulphonyl chloride occurs with various polyhydric alcohols derived from bile acids, as evidenced from the products of reduction of the sulphonates with lithium aluminium hydride. With both 5α- and 5β-cholane derivatives, a C 3 equatorial hydroxyl group exhibits comparable reactivity to the terminal primary hydroxyl group, generated from the bile acid carboxylic group, towards both sulphonyl chlorides. With axial hydroxyl groups at C 7 and C 12, toluene-p-sulphonate formation is much more difficult than methane- sulphonate formation. Reduction by means of lithium aluminium hydride of equatorial sulphonate esters at C 7 and C 12 gives rise to a methylene group, but the axial sulphonates under the same conditions give the axial alcohol. The same clear distinction between equatorial and axial sulphonate esters is not observed at C 3 and C 6, but 17α- methanesulphonyloxy-5α-androstane gives 5α-androstane and the 17β- ester gives 17β-hydroxy-5α-androstane. Reduction of 12-oximino groups in both 5α- and 5β-cholanes with sodium and ethanol, hydrogen in the presence of a catalyst, or lithium aluminium hydride gives solely the 12α-amino compound.

scholarly journals Studies on the formation of complex oxidation and condensation products of phenols. Part III. -Rearrangements of oxidation-reduction type in the diquinone group

1933 ◽  
Vol 143 (848) ◽  
pp. 223-228 ◽  
Keyword(s):  
Hydroxyl Group ◽  
Hydrogen Atoms ◽  
Blue Colour ◽  
Highly Active ◽  
Oxidation Reduction ◽  
Intramolecular Reactions ◽  
Trimethyl Ether ◽  
Free Hydroxyl ◽  
Ethereal Oxygen ◽  
Complex Oxidation

The diquinones have been but little investigated, and as they contain two condensed highly active quinonid systems it is to be anticipated that they should be capable of interesting intramolecular reactions. When heated to 210-215º, 4 : 4'-dimethoxydiquinone is rapidly converted into a red crystalline isomeride (yield, 90%), soluble in alkali with an intense blue colour, and yielding a mono-acetate indicating the occurrence of a free hydroxyl group. Two hydrogen atoms are taken up on reduction, and the phenolic product yields a triacetate and a trimethyl ether. It follows that of the four carbonyl oxygens of 4 : 4'-dimethoxydiquinone, one has been converted into a hydroxyl group, and another which does not exhibit any functional activity, is probably present as ethereal oxygen. These results led to formula (III) as representing the product of rearrangement.

scholarly journals Synthesis and Characterizations of Dipeptide Derivative of Gentamicin

2019 ◽  
Vol 28 (2) ◽  
pp. 73-82
Author(s):  
Oun D. Khudair ◽  
Diar A. Fatih
Keyword(s):  
Acid Chloride ◽  
Solution Method ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Free Hydroxyl ◽  
Ester Linkage ◽  
Amine Groups ◽  
Conventional Solution ◽  
Dipeptide Derivative

Abstract       The target derivative are gentamicin linked with L-Val- L-Ala by an ester linkage. These were synthesized by esterification method, which included the reaction of -OH hydroxyl group on (carbon No.5) of gentamicin with the acid chloride of the corresponding dipeptide, The preparation of new derivative of gentamicin involved protected the primary & secondary amine groups of Gentamicin, by Ethylchloroformate (ECF) to give N-carbomethoxy Gentamicin which was used for further chemical synthesis involving the free hydroxyl groups. Then prepared dipeptide (L-Val- L-Ala) by conventional solution method in present DCC & HoBt then reacted with thionyl chloride to prepared acid chloride of dipeptides, then after, linked by ester linkage to N-protection gentamicin in present pyridine as base, finally deportation the amino group of synthesized compound by using TFAA in present anisole. The characterization of the titled compounds were performed utilizing FTIR spectroscopy, CHNS elemental analysis, and by measurements of their physical properties.  

The Dielectic properties of Crystalline Alcohols containing sterically hindered Hydroxyl groups

1953 ◽  
Vol 6 (2) ◽  
pp. 104 ◽  
Author(s):  
RJ Meakins
Keyword(s):  
Hydrogen Bonding ◽  
Hydroxyl Group ◽  
Appreciable Amount ◽  
Hydroxyl Groups ◽  
Dipole Orientation ◽  
Hindered Rotation ◽  
Dielectric Absorption ◽  
Free Hydroxyl ◽  
Sterically Hindered ◽  
High Dielectric

It has been previously suggested that the high dielectric absorption of certain crystalline forms of long-chain alcohols is associated with hydrogen-bonding of the hydroxyl groups. This theory is supported by the results given in the present paper, which show that with other alcohols, in which the hydroxyl groups are sterically hindered, the loss is almost completely eliminated. The smallest losses are obtained with triphenylcarbinol and cholesterol which both possess hydroxyl groups embedded in a bulky molecular structure. For the former compound, infra-red data from the literature indicate the absence of any appreciable amount of hydrogen-bonding and are thus in agreement with the evidence from dielectric measurements. High frequency absorption observed in these compounds is considered to be associated with dipole orientation resulting from hindered rotation of the free hydroxyl groups. The effects of steric hindrance of the hydroxyl group are also observed in tert.-butanol.

Studies on the Lignin of Eucalyptus regnans F. Muell. V. Ethanol Lignin

1953 ◽  
Vol 6 (1) ◽  
pp. 44
Author(s):  
JWT Merewether
Keyword(s):  
Molecular Weight ◽  
Acetic Anhydride ◽  
Hydrogen Chloride ◽  
Benzoyl Chloride ◽  
Aqueous Alkali ◽  
Carbonyl Groups ◽  
Equivalent Weight ◽  
Eucalyptus Regnans

Lignin has been isolated from Eucalyptus regnans F. Muell. by refluxing with ethanolic hydrogen chloride, and the product separated into an ether-insoluble ethanol lignin-A and an ether-soluble ethanol lignin-B. Ethanol lignin-A has an equivalent weight of 1400 and, on the assumption that the molecular weight is of this order, contains two ethoxyl and nine methoxyl groups. Acetic anhydride and benzoyl chloride in pyridine yield respectively a hepta-acetate and heptabenzoate, while benzoyl chloride in aqueous alkali yields a pentabenzoate. Diazomethane yields a dimethyl derivative which gives a penta-acetate on acetylation. Schotten-Baumann benzoylation of this dimethyl derivative yields a dibenzoate. Two carbonyl groups are present, as shorn by the formation of a bisphenylhydrazone and a bis-p-nitrophenylhydrazone. The data are consistent with the formula C59H38O10(OC2H5)2(OCH3)9(OH)7.

The hydroxyl stretching frequencies and conformations of Flavan-4-ols and Thiaflavan-4-ols

1969 ◽  
Vol 22 (11) ◽  
pp. 2337 ◽  
Author(s):  
GF Katekar ◽  
AG Moritz
Keyword(s):  
Carbon Tetrachloride ◽  
Benzene Ring ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Frequency Shifts ◽  
Characteristic Frequencies ◽  
Carbon Tetrachloride Solution ◽  
Free Hydroxyl ◽  
Related Compounds

The hydroxyl stretching frequencies of some 2,4-cis and 2,4-trans flavan-4-ols, thiaflavan-4-ols, and related compounds have been measured in dilute carbon tetrachloride solution. Characteristic frequencies are observed at 3626�2 cm-1 (free hydroxyl), 3616�1, and 3597�2 cm-1. The 3616 and 3597 cm-1 bands are assigned to pseudo-axial and pseudo-equatorial hydroxyl groups respectively. Evidence is presented to show that the frequency shifts arise from differences in the interaction of the hydroxyl group with the π-electrons of the fused benzene ring, and that these flavans and thiaflavans exist in half- chair, rather than sofa conformations.

scholarly journals 3-O-Carbamoyl-5,7,20-O-trimethylsilybins: Synthesis and Preliminary Antiproliferative Evaluation

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6421
Author(s):  
Sitong Wu ◽  
Guanglin Chen ◽  
Qiang Zhang ◽  
Guangdi Wang ◽  
Qiao-Hong Chen
Keyword(s):  
Prostate Cancer ◽  
Cell Proliferation ◽  
Cancer Cell ◽  
Water Solubility ◽  
Prostate Cancer Cell ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Alcoholic Hydroxyl

To search for novel androgen receptor (AR) modulators for the potential treatment of castration-resistant prostate cancer (CRPC), naturally occurring silibinin was sought after as a lead compound because it possesses a moderate potency towards AR-positive prostate cancer cells and its chemical scaffold is dissimilar to all currently marketed AR antagonists. On the basis of the structure–activity relationships that we have explored, this study aims to incorporate carbamoyl groups to the alcoholic hydroxyl groups of silibinin to improve its capability in selectively suppressing AR-positive prostate cancer cell proliferation together with water solubility. To this end, a feasible approach was developed to regioselectively introduce a carbamoyl group to the secondary alcoholic hydroxyl group at C-3 without causing the undesired oxidation at C2–C3, providing an avenue for achieving 3-O-carbamoyl-5,7,20-O-trimethylsilybins. The application of the synthetic method can be extended to the synthesis of 3-O-carbamoyl-3′,4′,5,7-O-tetramethyltaxifolins. The antiproliferative potency of 5,7,20-O-trimethylsilybin and its nine 3-carbamoyl derivatives were assessed in an AR-positive LNCaP prostate cancer cell line and two AR-null prostate cancer cell lines (PC-3 and DU145). Our preliminary bioassay data imply that 5,7,20-O-trimethylsilybin and four 3-O-carbamoyl-5,7,20-O-trimethylsilybins emerge as very promising lead compounds due to the fact that they can selectively suppress AR-positive LNCaP cell proliferation. The IC50 values of these five 5,7,20-O-trimethylsilybins against the LNCaP cells fall into the range of 0.11–0.83 µM, which exhibit up to 660 times greater in vitro antiproliferative potency than silibinin. Our findings suggest that carbamoylated 5,7,20-O-trimethylsilybins could serve as a natural product-based scaffold for new antiandrogens for lethal castration-resistant prostate cancer.

The Course of Autoöxidation Reactions in Polyisoprene and Allied Compounds. III. The Oxidation of Rubber in the Presence of Acetic Acid or Acetic Anhydride

1944 ◽  
Vol 17 (2) ◽  
pp. 267-276
Author(s):  
George F. Bloomfield
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Chain Scission ◽  
Considerable Proportion ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Free Hydroxyl ◽  
Hydrolysis Of ◽  
Oxygenated Products ◽  
Oxidative Attack

Abstract Oxidation of rubber by oxygen in the presence of acetic anhydride leads to formation of highly oxygenated products containing a considerable proportion of acetoxyl groups. The residual unsaturation of the products of highest acetoxyl content, taken in conjunction with other analytical characteristics, indicates that three, rather than two, acetoxyl groups normally combine with each isoprene unit attacked. Although the bulk of the oxygen introduced is present in the form of acetoxyl groups, a portion occurs as carboxyl and carbonyl groups; also, whenever acetic acid is used (partly or wholly) in place of acetic anhydride, some free hydroxyl groups appear in the oxidized rubber. The proportions of carboxyl and carbonyl groups observed can be correlated satisfactorily with the extent of chain-scission occurring during the oxidation, the groups in question forming the new ends of the severed molecules. Hydrolysis of the acetylated products yields hydroxy acids, which readily undergo lactonic elimination of water. Acetic anhydride and acetic acid can clearly act as auxiliary reagents in autoöxidation reactions, and the detailed results obtained with rubber can be best accounted for on the basis of α-methylene peroxidation, followed by decay reactions involving incorporation of the auxiliary reagent as well as oxidative attack at the double bonds of the rubber.

Studies on the Lignin of Eucalyptus regnans. III. The Isolation of an Alkali Lignin from Sulphate Pulping

1949 ◽  
Vol 2 (1) ◽  
pp. 117
Author(s):  
JWT Merewether
Keyword(s):  
Acetic Anhydride ◽  
Alkaline Hydrolysis ◽  
Empirical Formula ◽  
Benzoyl Chloride ◽  
Dimethyl Sulphate ◽  
Hydroxyl Groups ◽  
Equivalent Weight ◽  
Eucalyptus Regnans ◽  
Alkali Lignin ◽  
Hydrolysis Of

An alkali lignin containing no sulphur has been obtained as a by-product from the sulphate pulping of Eucalyptus regnans. Like other alkali lignins it contains hydroxyl groups, both acidic and alcoholic, as well as methoxyl groups. Acetic anhydride in pyridine yields an octoacetyl derivative which is readily hydrolysed by boiling water to a heptacetyl derivative. In pyridine, benzoyl chloride yields an octobenzoyl derivative while in aqueous alkali it yields a hexabenzoyl compound. Dimethyl sulphate yields a heptamethyl alkali lignin, diazomethane a hexamethyl derivative, while cold alkaline hydrolysis of the latter gives a pentamethyl derivative, and hot alkaline hydrolysis yields an anhydrotrimethyl alkali lignin. One of the methoxyl groups formed by methylation is unstable to acetylation by acetic anhydride in pyridine, heptamethyl alkali lignin yielding a hexamethyldiacetyl derivative, hexamethyl alkali lignin a pentamethyltriacetyl derivative, pentamethyl alkali lignin a tetramethyltetracetyl derivative, and anhydrotrimethyl alkali lignin the corresponding anhydrodimethyltetracetyl alkali lignin. Triphenylchloromethane in pyridine yields a monotrityl derivative.p-Nitrophenylhydrazine gives a di-p-nitrophenylhydrazone and phenylhydrazine a phenylhydrazone-osazone. Potentiometric titration shows two points of inflection and an equivalent weight of 863. The data are consistent with the empirical formula C92Hl04O34(1754) or C73H54O9,(OCH3)14,(OH)3,C(OH),CO-CH20H,C0,COOH

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