Regioselective Deacetylation of Fully Acetylated Mono- and Di-Saccharides With Hydrazine Hydrate

1996 ◽  
Vol 49 (3) ◽  
pp. 293 ◽  
Author(s):  
R Khan ◽  
PA Konowicz ◽  
L Gardossi ◽  
M Matulova ◽  
S Degennaro
Keyword(s):  
Hydrazine Hydrate ◽  
Hydroxy Group ◽  
Lower Yield ◽  
Free Hydroxy Group ◽  
Regioselective Deacetylation ◽  
Hydroxy Groups ◽  
Selective Deacetylation

Selective deacetylation reactions of the peracetylated reducing disaccharides (1), (5), (9), (15), β-D- glucopyranose (17) and 2-acetamido-2-deoxy-β-D-glucopyranose (19), with 1.2 equiv. Of hydrazine hydrate in acetonitrile, gave predominantly the corresponding heptaacetates (2), (6), (10), (16), the tetraacetate (18) and the triacetate (20), with the free hydroxy group at C1. Reaction of (1) with 1.2 equiv. of hydrazine hydrate in N,N- dimethylformamide also afforded the heptaacetate (2), but in lower yield. When reactions of (1), (5) and (9) were performed with 2.5 equiv. of hydrazine hydrate, deacetylation also occurred at other positions to afford the corresponding hexaacetates (3), (7), (11) and (12), with hydroxy groups at C 1,2 or C 1,3, and the pentaacetates (4), (8) and (13), with hydroxy groups at C 1,2,3. Maltose octaacetate (9), in addition, yielded the tetraacetate (14) in which the free hydroxy groups were located at C1,2,2',3. Compound (15) on treatment with 2.5 equiv. of hydrazine hydrate afforded an intractable mixture. The reaction of methyl 2,3,4,6-tetra-O-acetyl-α-D-glucopyranoside (21) with 2.5 equiv. of hydrazine hydrate gave the 3,4,6-triacetate (22), a mixture of the 2,6- and the 3,6-diacetates (23) and (24), respectively, the 4,6-diacetate (25), and the 6-acetate (26).

Participation of the oxygen-containing substituent in alkaline saponification of 3,4a-disubstituted 4,4-dimethyl-5,6β-epoxy-A-homo-5β-cholestane derivatives

1986 ◽  
Vol 51 (4) ◽  
pp. 930-936 ◽  
Author(s):  
Helena Velgová
Keyword(s):  
Hydroxy Group ◽  
Acetoxy Group ◽  
Epoxide Ring ◽  
Main Component ◽  
Hydroxy Groups

Alkaline saponification of the 3-acetoxy group in 3,4a-disubstituted 4,4-dimethyl-5,6β-epoxy-A-homo-5βcholestane derivatives I-VI was studied. It was found that the 3α- and 4aα-hydroxy groups participated in the cleavage of the 5β,6β-epoxide ring in the derivatives II-IV: the 5(O)n participation by the 3α-hydroxy group (the derivatives III and IV) led to formation of the transannular 3α,5α-epoxides XII and XIV whereas the participation by the 4aα-hydroxy group (the derivatives II and IV) gave rise to the 4aα,5α-epoxides IX and XV. The 5(O)n participation by the 3α-hydroxy group predominated over the preparation by the 4aα-hydroxy group. In the case of the 4a-keto epoxides V and VI the retroaldol-aldol type isomerization led to formation of 3β-hydroxy-4,4-dimethyl-5,6β-epoxy-A-homo-5β-cholestan-4a-one as the main component of the equilibration mixtures.

Synthesis of (15E)-17β-hydroxy-5α-androstane-3,15-dione 15-[O-(Carboxymethyl)]oxime, New Hapten for Dihydrotestosterone (17β-hydroxy-5α-androstan-3-one)

1997 ◽  
Vol 62 (10) ◽  
pp. 1642-1649 ◽  
Author(s):  
Ivan Černý ◽  
Tereza Slavíková ◽  
Vladimír Pouzar
Keyword(s):  
Hydroxy Group ◽  
Carboxy Group ◽  
Title Compound ◽  
Oxidative Cleavage ◽  
Hydroxy Derivative ◽  
Borohydride Reduction ◽  
Protecting Group ◽  
Free Hydroxy Group

Addition of 4-methoxybenzyl alcohol to 3β-hydroxy-5α-androst-15-en-17-one gave the mixture of isomeric 15-(4-methoxyphenyl)methoxy derivatives from which, after acetylation and chromatography, the major 15β isomer was separated. Borohydride reduction gave 17β-hydroxy derivative which was protected as methoxymethyl ether. Oxidative cleavage of protecting group at position 15 and the subsequent Jones oxidation afforded corresponding 15-ketone. Its oximation with O-(carboxymethyl)hydroxylamine, deacetylation and methylation with diazomethane gave protected O-(carboxymethyl)oxime derivative with free hydroxy group at position 3. Its oxidation afforded dihydrotestosterone derivative and successive deprotection of position 17 and of carboxy group led to final (15E)-17β-hydroxy-5α-androstane-3,15-dione 15-[O-(carboxymethyl)]oxime. The title compound was designed as dihydrotestosterone hapten for heterologous radioimmunoassays.

scholarly journals Linking Aromatic Hydroxy Metabolic Functionalization of Drug Molecules to Structure and Pharmacologic Activity

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2119 ◽  
Author(s):  
Babiker El-Haj ◽  
Samrein Ahmed ◽  
Mousa Garawi ◽  
Heyam Ali
Keyword(s):  
Benzene Ring ◽  
Hydroxy Group ◽  
Water Solubility ◽  
Parent Drug ◽  
Drug Action ◽  
Alkoxy Group ◽  
Drug Molecules ◽  
Drug Classes ◽  
Pharmacologic Activity ◽  
Hydroxy Groups

Drug functionalization through the formation of hydrophilic groups is the norm in the phase I metabolism of drugs for the modification of drug action. The reactions involved are mainly oxidative, catalyzed mostly by cytochrome P450 (CYP) isoenzymes. The benzene ring, whether phenyl or fused with other rings, is the most common hydrophobic pharmacophoric moiety in drug molecules. On the other hand, the alkoxy group (mainly methoxy) bonded to the benzene ring assumes an important and sometimes essential pharmacophoric status in some drug classes. Upon metabolic oxidation, both moieties, i.e., the benzene ring and the alkoxy group, produce hydroxy groups; the products are arenolic in nature. Through a pharmacokinetic effect, the hydroxy group enhances the water solubility and elimination of the metabolite with the consequent termination of drug action. However, through hydrogen bonding, the hydroxy group may modify the pharmacodynamics of the interaction of the metabolite with the site of parent drug action (i.e., the receptor). Accordingly, the expected pharmacologic outcome will be enhancement, retention, attenuation, or loss of activity of the metabolite relative to the parent drug. All the above issues are presented and discussed in this review using selected members of different classes of drugs with inferences regarding mechanisms, drug design, and drug development.

scholarly journals Crystal structure oftrans-N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyl)oxamide methanol monosolvate

2016 ◽  
Vol 72 (7) ◽  
pp. 918-921
Author(s):  
Miguel-Ángel Velázquez-Carmona ◽  
Sylvain Bernès ◽  
Francisco Javier Ríos-Merino ◽  
Yasmi Reyes Ortega
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Hydroxy Group ◽  
Molecular Conformation ◽  
Methanol Molecule ◽  
Molecular Symmetry ◽  
Methyl Group ◽  
Supramolecular Motifs ◽  
Butyl Group ◽  
Hydroxy Groups

The here crystallized oxamide was previously characterized as an unsolvated species [Jímenez-Pérezet al.(2000).J. Organomet. Chem.614–615, 283–293], and is now reported with methanol as a solvent of crystallization, C30H44N2O4·CH3OH, in a different space group. The introduction of the solvent influences neither the molecular symmetry of the oxamide, which remains centrosymmetric, nor the molecular conformation. However, the unsolvated molecule crystallized as an ordered system, while many parts of the solvated crystal are disordered. The hydroxy group in the oxamide is disordered over two chemically equivalent positions, with occupancies 0.696 (4):0.304 (4); onetert-butyl group is disordered by rotation about the C—C bond, and was modelled with three sites for each methyl group, each one with occupancy 1/3. Finally, the methanol solvent, which lies on a twofold axis, is disordered by symmetry. The disorder affecting hydroxy groups and the solvent of crystallization allows the formation of numerous supramolecular motifs using four hydrogen bonds, with N—H and O—H groups as donors and the oxamide and methanol molecule as acceptors.

The Synthesis of (R)-2',3'-Dihydroxypropyl 5-Deoxy-5-Dimethylarsinyl-β-D-Riboside, a Naturally Occurring Arsenic-Containing Carbohydrate

1987 ◽  
Vol 40 (11) ◽  
pp. 1901 ◽  
Author(s):  
DP Mcadam ◽  
AMA Perera ◽  
RV Stick
Keyword(s):  
Natural Product ◽  
Hydroxy Group ◽  
Title Compound ◽  
Protecting Groups ◽  
Giant Clam ◽  
Free Hydroxy Group ◽  
Naturally Occurring ◽  
Step Procedure ◽  
Tridacna Maxima ◽  
Subsequent Chemical

The synthesis of the title compound, isolated from the brown kelp ( Ecklonia radiata ) or the giant clam (Tridacna maxima), is reported. Glycosidation of 1-O-acetyl-2,3,5-tri- O- benzoyl -β-D-ribose, either directly with (S)-1,2-di-O-benzylglycerol or via the derived orthoester with (S)-1,2-O-isopropylideneglycerol, led to two fully protected glycerol β-D- ribofuranosides. Subsequent chemical manipulations led to a common intermediate having a free hydroxy group at C5 of the D-ribose residue. Replacement of this hydroxy group by a chlorine atom allowed the introduction of the dimethylarsinyl group at C5 in a two-step procedure, and removal of protecting groups provided the natural product.

scholarly journals Threefold helical assembly via hydroxy hydrogen bonds: the 2:1 co-crystal of bicyclo[3.3.0]octane-endo-3,endo-7-diol and bicyclo[3.3.0]octane-endo-3,exo-7-diol

2021 ◽  
Vol 77 (3) ◽  
pp. 270-276
Author(s):  
Isa Y. H. Chan ◽  
Mohan M. Bhadbhade ◽  
Roger Bishop
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Hydroxy Group ◽  
Network Structure ◽  
General Position ◽  
Three Dimensional ◽  
Screw Axis ◽  
Hydroxy Groups

Reduction of bicyclo[3.3.0]octane-3,7-dione yields a mixture of the endo-3,endo-7-diol and endo-3, exo-7-diol (C8H14O2) isomers (5 and 6). These form (5)2·(6) co-crystals in the monoclinic P21/n space group (with Z = 6, Z′ = 1.5) rather than undergoing separation by means of fractional recrystallization or column chromatography. The molecule of 5 occupies a general position, whereas the molecule of 6 is disordered over two orientations across a centre of symmetry with occupancies of 0.463 (2) and 0.037 (2). Individual diol hydroxy groups associate around a pseudo-threefold screw axis by means of hydrogen bonding. The second hydroxy group of each diol behaves in a similar manner, generating a three-dimensional hydrogen-bonded network structure. This hydrogen-bond connectivity is identical to that present in three known helical tubuland diol–hydroquinone co-crystals, and the new crystal structure is even more similar to two homologous aliphatic diol co-crystals.

scholarly journals Crystal structure of 2,4-di-tert-butyl-6-(hydroxymethyl)phenol

2016 ◽  
Vol 72 (11) ◽  
pp. 1614-1617
Author(s):  
Ane I. Aranburu Leiva ◽  
Sophie L. Benjamin ◽  
Stuart K. Langley ◽  
Ryan E. Mewis
Keyword(s):  
Crystal Structure ◽  
Bond Length ◽  
Hydroxy Group ◽  
Chair Conformation ◽  
Alcohol Group ◽  
Phenolic Oxygen ◽  
Compound C ◽  
Pendant Arm ◽  
Phenol Hydroxy Group ◽  
Hydroxy Groups

The title compound, C15H24O2, is an example of a phenol-based pendant-arm precursor. In the molecule, the phenol hydroxy group participates in an intramolecular O—H...O hydrogen bond with the pendant alcohol group, forming anS(6) ring. This ring adopts a half-chair conformation. In the crystal, O—H...O hydrogen bonds connect molecules related by the 31screw axes, forming chains along thecaxis. The C—C—O angles for the hydroxy groups are different as a result of the type of hybridization for the C atoms that are involved in these angles. The C—C—O angle for the phenol hydroxy group is 119.21 (13)°, while the angle within the pendant alcohol is 111.99 (13)°. The bond length involving the phenolic oxygen is 1.3820 (19) Å, which contrasts with that of the alcoholic oxygen which is 1.447 (2) Å. The former is conjugated with the aromatic ring and so leads to the observed shorter bond length.

THE ALKALOIDS OF FUMARIACEOUS PLANTS: XI. TWO NEW ALKALOIDS, CORLUMINE AND CORLUMIDINE, AND THEIR CONSTITUTIONS

1936 ◽  
Vol 14b (9) ◽  
pp. 325-327 ◽  
Author(s):  
Richard H. F. Manske
Keyword(s):  
Hydroxy Group ◽  
Chemical Examination ◽  
Free Hydroxy Group ◽  
Optical Antipode

A new alkaloid, corlumine, has been isolated from Corydalis scouleri, C. sibirica and Dicentra cucullaria. Chemical examination disclosed its isomerism with adlumine with which, furthermore, it is structurally identical. It differs from the latter only in the disposition of the substituents about the two asymmetric C-atoms, but it is not the optical antipode of adlumine. Corlumidine is O-desmethyl corlumine and has been found only in C. scouleri, and on methylation with diazomethane yields corlumine. The free hydroxy-group is probably present in the 7-position of the isoquinoline nucleus.

scholarly journals Chemical and chemoenzymatic routes to bridged homoarabinofuranosylpyrimidines: Bicyclic AZT analogues

2022 ◽  
Vol 18 ◽  
pp. 95-101
Author(s):  
Sandeep Kumar ◽  
Jyotirmoy Maity ◽  
Banty Kumar ◽  
Sumit Kumar ◽  
Ashok K Prasad
Keyword(s):  
Hydroxy Group ◽  
Chemical Method ◽  
Secondary Hydroxy Group ◽  
Synthetic Pathway ◽  
Conformationally Restricted ◽  
Hydroxy Groups ◽  
Azt Analogues

Conformationally restricted diastereomeric homoarabinofuranosylpyrimidines (AZT analogue), i.e., (5′R)-3′-azido-3′-deoxy-2′-O,5′-C-bridged-β-ᴅ-homoarabinofuranosylthymine and -uracil had been synthesized starting from diacetone ᴅ-glucofuranose following chemoenzymatic and chemical routes in 34–35% and 24–25% overall yields, respectively. The quantitative and diastereoselective acetylation of primary hydroxy over two secondary hydroxy groups present in the key nucleoside precursor was mediated with Lipozyme® TL IM in 2-methyltetrahydrofuran following a chemoenzymatic pathway. Whereas, the protection of the primary hydroxy over the lone secondary hydroxy group in the key azido sugar precursor was achieved using bulky tert-butyldiphenylsilyl chloride (TBDPS-Cl) in pyridine in 92% yield following a chemical synthetic pathway. The chemoenzymatic method was found to be superior over the chemical method in respect of the number of synthetic steps and overall yield of the final product.

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